Patent Publication Number: US-10768505-B2

Title: Driver assistance apparatus and vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of an earlier filing date and right of priority to Korean Patent Application No. 10-2016-0042968, filed on Apr. 7, 2016 in the Korean Intellectual Property Office, the content of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a driver assistance apparatus and a vehicle. 
     BACKGROUND 
     A vehicle is an apparatus that transports a user riding therein in a desired direction. An example of a vehicle is an automobile. 
     For the convenience of a user who uses a vehicle, a variety of sensors and electronic devices are typically mounted in vehicles. For example, some vehicles implement an Advanced Driver Assistance System (ADAS) that utilizes various sensors in the vehicle to provide convenience functions for a user of the vehicle. In addition, autonomous vehicles have actively been developed. 
     SUMMARY 
     In one aspect, a driver assistance apparatus may include a camera provided in a vehicle and configured to acquire an image; and a processor configured to process the image. The camera may include an image sensor; and a variable lens that includes a liquid crystal layer and configured to alter light that is introduced into the image sensor based on an arrangement of liquid crystal molecules included in the liquid crystal layer. The arrangement of the liquid crystal molecules in the liquid crystal layer may depend on an applied voltage. 
     In some implementations, the processor may be configured to alter a focal distance of the variable lens by controlling the arrangement of the liquid crystal molecules. 
     In some implementations, the driver assistance apparatus may further include an interface unit. The processor may be further configured to: receive, via the interface unit, driving information for the vehicle; and change the focal distance of the variable lens based on the received driving information. 
     In some implementations, the received driving information may include driving speed information for the vehicle. The processor may be further configured to, based on a driving speed of the vehicle indicated by the driving speed information: increase the focal distance of the variable lens based on a determination that the driving speed is increased; and reduce the focal distance of the variable lens based on a determination that the driving speed is reduced. 
     In some implementations, the driving information may include steering information or turn-signal information for the vehicle. The processor may be configured to change the focal distance of the variable lens based on at least one of the steering information or the turn-signal information. 
     In some implementations, the steering information may include a steering value that indicates an amount of steering to the left or the right relative to a direction of travel for the vehicle. The processor may be configured to reduce the focal distance of the variable lens based on a determination that the steering value is greater than or equal to a threshold steering value. 
     In some implementations, driving information may include path information for the vehicle. The processor may be further configured to change the focal distance of the variable lens based on the path information. 
     In some implementations, the driver assistance apparatus may further include an input unit. The processor may be further configured to change the focal distance of the variable lens based on an input signal received via the input unit. 
     In some implementations, the processor may be further configured to detect an object in the image acquired via the camera; and change the focal distance of the variable lens based on the object detected in the image. 
     In some implementations, the processor may be further configured to change the focal distance of the variable lens based on a distance to the object or based on a position of the object. 
     In some implementations, the processor may be further configured to increase the focal distance of the variable lens based on a determination that the distance to the object is increased; and reduce the focal distance of the variable lens based on a determination that the distance to the object is reduced. 
     In some implementations, the processor may be configured to, based on changing the focal distance of the variable lens, change a Region of Interest (ROI) of the image based on the position of the object. 
     In some implementations, the processor may be further configured to reduce the focal distance of the variable lens based on a determination that a road intersection is detected as the object in the image. 
     In some implementations, the processor may be further configured to: detect an object in the image acquired via the camera; track variations in the object detected in the image based on varying the focal distance of the variable lens; and determine a distance to the object based on the tracked variations in the object that result from varying the focal distance. 
     In another aspect, a driver assistance apparatus may include a first camera provided in a vehicle and configured to acquire a first image; a second camera provided in the vehicle and configured to acquire a second image; and a processor configured to process the first image and the second image. The first camera may include a first image sensor; and a first variable lens including a first liquid crystal layer and configured to alter light that is introduced into the first image sensor based on an arrangement of liquid crystal molecules included in the first liquid crystal layer, the arrangement of the liquid crystal molecules in the first liquid crystal layer being dependent on a first applied voltage. The second camera may include a second image sensor; and a second variable lens including a second liquid crystal layer and configured to alter light that is introduced into the second image sensor based on an arrangement of liquid crystal molecules included in the second liquid crystal layer, the arrangement of the liquid crystal molecules being dependent on a second applied voltage. 
     In some implementations, the processor may be further configured to: change a focal distance of the first variable lens by controlling the arrangement of the liquid crystal molecules included in the first liquid crystal layer; and change a focal distance of the second variable lens by controlling the arrangement of the liquid crystal molecules included in the second liquid crystal layer. 
     In some implementations, the processor may be configured to change the focal distance of the first variable lens and the focal distance of the second variable lens differently from each other. 
     In some implementations, the processor may be configured to acquire at least one stereo image by processing each of the first image and the second image; and perform disparity calculation based on the at least one stereo image. 
     In some implementations, the processor may be configured to acquire at least one stereo image based on the received first image and the received second image by: detecting an object based on the first image; and changing a focal distance of the first variable lens or a focal distance of the second variable lens based on the object detected in the first image. 
     In another aspect, a driver assistance apparatus may include: a camera provided in a vehicle and configured to acquire an image; and a processor configured to process the image. The camera may include: an image sensor; and a variable lens configured to alter light that is introduced into the image sensor by varying an interface formed between a polar fluid and a non-polar fluid based on a voltage applied thereto. 
     All or part of the features described throughout this disclosure may be implemented as a computer program product including instructions that are stored on one or more non-transitory machine-readable storage media, and that are executable on one or more processing devices. All or part of the features described throughout this disclosure may be implemented as an apparatus, method, or electronic system that can include one or more processing devices and memory to store executable instructions to implement the stated functions. 
     Details of some implementations are included in the following description and the accompanying drawings. The description and examples below are given by way of illustration only, and various changes and modifications will be apparent. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram illustrating an example of the external appearance of a vehicle in accordance with an implementation; 
         FIG. 2  is a block diagram illustrating an example of a vehicle in accordance with an implementation; 
         FIG. 3  is a diagram illustrating an example of a vehicle camera in accordance with an implementation; 
         FIG. 4  is a diagram illustrating an example of the vehicle camera in accordance with the implementation; 
         FIG. 5  is a diagram illustrating a cutaway side sectional view of an example of the vehicle camera taken along line A-B of  FIG. 3  in accordance with the implementation; 
         FIG. 6  is a diagram illustrating a perspective view of an example of a vehicle camera in accordance with an implementation; 
         FIG. 7  is a diagram illustrating an exploded perspective view of an example of the vehicle camera in accordance with the implementation; 
         FIG. 8  is a diagram illustrating a cutaway side sectional view of an example of the vehicle camera taken along line C-D of  FIG. 6  in accordance with the implementation; 
         FIG. 9  is a diagram illustrating an enlarged cutaway side sectional view of an example of a portion CR 1  of  FIG. 5  or portion CR 2  of  FIG. 8 ; 
         FIGS. 10A to 11  are diagrams illustrating enlarged side views of examples of portion HS of  FIG. 9 , which are referenced to describe various implementations of a holder and at least one heating element provided in the holder; 
         FIG. 12  is a diagram illustrating an example of a variable lens in accordance with an implementation; 
         FIG. 13  is a diagram illustrating an example of a first substrate in accordance with an implementation; 
         FIGS. 14A to 14C  are diagrams illustrating examples of an operation in which different levels of voltage are respectively applied to each of a plurality of first electrodes in accordance with an implementation; 
         FIG. 15  is a diagram illustrating an example of an arrangement of the first electrodes in the left-right direction in accordance with an implementation; 
         FIG. 16  is a diagram illustrating an example of an arrangement of the first electrodes in the left-right direction and the up-down direction in accordance with an implementation; 
         FIGS. 17 and 18  are diagrams illustrating examples of a vehicle camera including a plurality of variable lenses in accordance with an implementation; 
         FIG. 19  is a diagram illustrating an example of a driver assistance apparatus  400  in accordance with an implementation; 
         FIGS. 20A to 21  are diagrams illustrating examples of a variable lens and operations of calculating a distance to an object using the variable lens in accordance with an implementation; 
         FIG. 22  is a flowchart illustrating an example of an operation of the driver assistance apparatus in accordance with an implementation; 
         FIGS. 23A and 23B  are diagrams illustrating examples of operations of changing the focal distance of the variable lens based on a driving speed in accordance with an implementation; 
         FIG. 24  is a diagram illustrating an example of an operation of changing the focal distance of the variable lens based on steering information or turn-signal information in accordance with an implementation; 
         FIG. 25  is a diagram illustrating an example of an operation of changing the focal distance of the variable lens based on predetermined path information in accordance with an implementation; 
         FIG. 26  is a flowchart illustrating an example of an operation of the driver assistance apparatus in accordance with an implementation; 
         FIG. 27  is a diagram illustrating an example of an operation of changing the focal distance of the variable lens based on an input signal in accordance with an implementation; 
         FIG. 28  is a flowchart illustrating an example of an operation of the driver assistance apparatus in accordance with an implementation; 
         FIG. 29  is a diagram illustrating an example of an operation of changing the focal distance of the variable lens based on a distance to an object in accordance with an implementation; 
         FIG. 30  is a diagram illustrating an example of an operation of changing the focal distance of the variable lens based on the position of the object in accordance with an implementation; 
         FIG. 31  is a diagram illustrating an example of an operation of changing the focal distance of the variable lens when an intersection is detected as the object in accordance with an implementation; 
         FIGS. 32A and 32B  are diagrams illustrating examples of the internal configuration of a processor for a vehicle camera that includes a stereo camera in accordance with an implementation; 
         FIGS. 33A and 33B  are diagrams illustrating examples of operating a processor (e.g., processor  470  of  FIG. 19 ) based on stereo images acquired respectively during first and second frame periods in accordance with an implementation; 
         FIG. 34  is a diagram illustrating an example of the internal configuration of the processor for a vehicle camera that includes a stereo camera in accordance with an implementation; 
         FIG. 35  is a diagram illustrating an example of binning and cropping in accordance with an implementation; 
         FIG. 36  is a diagram illustrating an example of an operation of producing a stereo image in accordance with an implementation; 
         FIG. 37  is a diagram illustrating an example of a first image in accordance with an implementation; 
         FIG. 38  is a diagram illustrating an example of a second image in accordance with an implementation; 
         FIG. 39  is a diagram illustrating an example of a stereo image produced based on the first image and the second image in accordance with an implementation; and 
         FIG. 40  is a diagram illustrating an example of the variable lens included in the driver assistance apparatus in accordance with an implementation. 
     
    
    
     DETAILED DESCRIPTION 
     A vehicle may utilize various sensors, such as a camera, to provide convenience functions for a user. Typically, a camera used as a sensor in a vehicle has a constant focal distance and does not implement appropriate adjustment of the focal distance of the camera based on, for example, a vehicle state or a driving state of the vehicle. 
     Implementations described herein provide a vehicular camera with a variable lens that is configured with a focal distance that is controllable by adjusting properties of the variable lens. 
     In some implementations, the variable lens includes a liquid crystal layer. In such implementations, the variable lens is configured to alter light based on an arrangement of liquid crystal molecules included in the liquid crystal layer. The arrangement of the liquid crystal molecules in the liquid crystal layer is dependent on an applied voltage. As such, in some implementations, the variable lens may be implemented to control a path of light that is introduced into an image sensor of the camera, thereby controlling a focal distance of the camera. 
     In some implementations, one or more processors may be configured to control the liquid crystal layer of the variable lens, and thereby control the focal distance of the camera. For example, in some implementations, an ADAS may be provided in the vehicle and may include one or more processors that control the variable lens. Such control may be based on, for example, state of the vehicle or a driving state of the vehicle, including surroundings of the vehicle. As such, the vehicle ADAS may control a focal distance of the camera to provide images that are appropriate for a particular driving scenario of the vehicle. 
     In some scenarios, implementations described herein may provide one or more effects as follows. 
     In some scenarios, the focal distance of a vehicle camera may be adjusted using a variable lens. 
     In some scenarios, the focal distance of the camera may be adjusted to suit a vehicle state or a driving situation of the vehicle. 
     In some scenarios, the focal distance of the camera may be appropriately adjusted to suit the purpose for which an advanced driver assistance system is used. 
     In some scenarios, the focal distance of the camera may be appropriately adjusted based on detected object information. 
     In some scenarios, through the adjustment of the focal distance of the camera, information corresponding to the situation may be provided, thus improving safe driving of a driver of the vehicle. 
     Effects of the present disclosure are not limited to the aforementioned effects and other effects are possible. 
     A vehicle as described in this disclosure may include an automobile, a motorcycle, or any suitable vehicle. Hereinafter, a description will be given based on a car. 
     A vehicle as described in this specification may be powered by any suitable power source, and may be, for example an internal combustion engine vehicle including an engine as a power source, a hybrid vehicle including both an engine and an electric motor as a power source, an electric vehicle including an electric motor as a power source, or any suitably powered vehicle. 
     In the following description, “the left side of the vehicle” refers to the left side in the forward driving direction of the vehicle, and “the right side of the vehicle” refers to the right side in the forward driving direction of the vehicle. 
       FIG. 1  is a view illustrating the external appearance of a vehicle in accordance with an implementation. 
     Referring to  FIG. 1 , the vehicle  100  may include wheels that are rotated by a power source, and a steering input device for adjusting the direction of travel of the vehicle  100 . 
     In some implementations, the vehicle  100  may be an autonomous vehicle. The autonomous vehicle enables bidirectional switching between an autonomous driving mode and a manual mode in response to user input. When switched to the manual mode, the autonomous vehicle  100  may receive driver input for driving via a driving operation device (e.g., driving operation device  121  in  FIG. 2 ). 
     The vehicle  100  may include a driver assistance apparatus  400 . The driver assistance apparatus  400  is an apparatus that assists a driver based on information acquired from various sensors. The driver assistance apparatus  400  may be referred to as an Advanced Driver Assistance System (ADAS). 
     The following description will be given based on a vehicle camera  200  that serves as a sensor used in the driver assistance apparatus  400 , without being limited thereto. In some implementations, the sensor may include a radar, Lidar, ultrasonic sensor, or infrared sensor, in addition to the vehicle camera  200 . 
     In addition, the following description will be given based on a mono camera  200   a  and a stereo camera  200   b , which serves as the vehicle camera  200  used in the driver assistance apparatus  400 , without being limited thereto. In some implementations, the vehicle camera  200  may include a triple camera, an Around View Monitoring (AVM) camera, a 360-degree camera, or an omnidirectional camera. 
     In the drawings, although the vehicle camera  200  used in the driver assistance apparatus  400  is illustrated as being mounted on a front windshield  10  in order to capture an image of the view to the front of the vehicle  100 , the vehicle camera  200  may capture an image of any direction including the front side, the rear side, the right side and the left side of the vehicle  100 . Accordingly, the vehicle camera  200  may be located at an appropriate position outside or inside the vehicle  100 . 
     In some implementations, the vehicle camera  200  may capture an image of the view inside the vehicle  100 . 
     “The overall length” refers to the length from the front end to the rear end of the vehicle  100 , “the overall width” refers to the width of the vehicle  100 , and “the overall height” refers to the height from the bottom of the wheel to the roof. In the following description, “the overall length direction L” may refer to the reference direction for the measurement of the overall length of the vehicle  100 , “the overall width direction W” may refer to the reference direction for the measurement of the overall width of the vehicle  100 , and “the overall height direction H” may refer to the reference direction for the measurement of the overall height of the vehicle  100 . 
       FIG. 2  is a block diagram referenced to describe the vehicle  100  in accordance with an implementation. 
     Referring to  FIG. 2 , the vehicle  100  may include a communication unit  110 , an input unit  120 , a sensing unit  125 , a memory  130 , an output unit  140 , a vehicle drive unit  150 , a controller  170 , an interface unit  180 , a power supply unit  190 , and the driver assistance apparatus  400 . 
     The communication unit  110  may include a short-range communication module  113 , a location information module  114 , an optical communication module  115 , and a V2X communication module  116 . 
     The communication unit  110  may include one or more Radio Frequency (RF) circuits or elements in order to perform communication with another device. 
     The short-range communication module  113  may assist short-range communication using at least one selected from among Bluetooth™, Radio Frequency IDdentification (RFID), Infrared Data Association (IrDA), Ultra-WideBand (UWB), ZigBee, Near Field Communication (NFC), Wireless-Fidelity (Wi-Fi), Wi-Fi Direct, and Wireless USB (Wireless Universal Serial Bus). 
     The short-range communication module  113  may form wireless area networks to perform the short-range communication between the vehicle  100  and at least one external device. For example, the short-range communication module  113  may exchange data with a mobile terminal of a passenger in a wireless manner. The short-range communication module  113  may receive weather information and road traffic state information (e.g., Transport Protocol Expert Group (TPEG) information) from the mobile terminal. When a user gets into the vehicle  100 , the mobile terminal of the user and the vehicle  100  may pair with each other automatically or as the user executes a pairing application. 
     The location information module  114  is a module for acquiring a location of the vehicle  100 . A representative example of the location information module  114  includes a Global Positioning System (GPS) module. For example, when the vehicle  100  utilizes a GPS module, a location of the vehicle  100  may be acquired using signals transmitted from GPS satellites. 
     In some implementations, the location information module  114  may be a component included in the sensing unit  125 , rather than a component included in the communication unit  110 . 
     The optical communication module  115  may include a light emitting unit and a light receiving unit. 
     The light receiving unit may convert light into electrical signals to receive information. The light receiving unit may include Photo Diodes (PDs) for receiving light. The photo diodes may convert light into electrical signals. For example, the light receiving unit may receive information regarding a preceding vehicle via light emitted from a light source included in the preceding vehicle. 
     The light emitting unit may include at least one light emitting element for converting electrical signals into light. Here, the light emitting element may be a Light Emitting Diode (LED). The light emitting unit converts electrical signals into light to thereby emit the light. For example, the light emitting unit may externally emit light via flickering of the light emitting element corresponding to a prescribed frequency. In some implementations, the light emitting unit may include an array of a plurality of light emitting elements. In some implementations, the light emitting unit may be integrated with a lamp provided in the vehicle  100 . For example, the light emitting unit may be at least one selected from among a headlight, a taillight, a brake light, a turn signal light, and a sidelight. For example, the optical communication module  115  may exchange data with another vehicle via optical communication. 
     The V2X communication module  116  is a module for performing wireless communication with a server or another vehicle. The V2X communication module  116  includes a module capable of realizing a protocol for communication between autonomous driving vehicles (V2V) or communication between an autonomous driving vehicle and an infrastructure (V2I). The vehicle  100  may perform wireless communication with an external server or another vehicle via the V2X communication module  116 . 
     The input unit  120  may include the driving operation device  121 , a microphone  123 , and a user input unit  124 . 
     The driving operation device  121  is configured to receive user input for the driving of the vehicle  100 . The driving operation device  121  may include a steering input device, a shift input device, an acceleration input device, and a brake input device. 
     The steering input device is configured to receive user input with regard to the direction of travel of the vehicle  100 . The steering input device may take the form of a steering wheel to enable steering input via rotation thereof. In some implementations, the steering input device may be configured as a touchscreen, a touch pad, or a button. 
     The shift input device is configured to receive input for selecting one of Park (P), Drive (D), Neutral (N), and Reverse (R) gears of the vehicle  100  from the user. The shift input device may take the form of a lever. In some implementations, the shift input device may be configured as a touchscreen, a touch pad, or a button. 
     The acceleration input device is configured to receive user input for the acceleration of the vehicle  100 . The brake input device is configured to receive user input for the speed reduction of the vehicle  100 . Each of the acceleration input device and the brake input device may take the form of a pedal. In some implementations, the acceleration input device or the brake input device may be configured as a touchscreen, a touch pad, or a button. 
     The microphone  123  may process external sound signals into electrical data. The processed data may be utilized in various ways according to a function that the vehicle  100  is performing. The microphone  123  may convert a user voice command into electrical data. The converted electrical data may be transmitted to the controller  170 . 
     In some implementations, the camera  200  or the microphone  123  may be components included in the sensing unit  125 , rather than components included in the input unit  120 . 
     The user input unit  124  is configured to receive information from the user. When information is input via the user input unit  124 , the controller  170  may control the operation of the vehicle  100  so as to correspond to the input information. The user input unit  124  may include a touch input unit or a mechanical input unit. In some implementations, the user input unit  124  may be located in a region of the steering wheel. In this case, the driver may operate the user input unit  124  with the fingers while gripping the steering wheel. 
     The sensing unit  125  is configured to sense various situations in the vehicle  100  or situations outside the vehicle  100 . To this end, the sensing unit  160  may include a collision sensor, a steering wheel sensor, a speed sensor, a gradient sensor, a weight sensor, a heading sensor, a yaw sensor, a gyro sensor, a position module, a vehicle forward/reverse sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor based on the rotation of the steering wheel, a vehicle interior temperature sensor, a vehicle interior humidity sensor, an ultrasonic sensor, an illumination sensor, an accelerator pedal position sensor, a brake pedal position sensor, etc. 
     The sensing unit  125  may acquire sensing signals with regard to, for example, vehicle collision information, vehicle driving direction information, vehicle location information (GPS information), vehicle angle information, vehicle speed information, vehicle acceleration information, vehicle tilt information, vehicle forward/reverse information, battery information, fuel information, tire information, vehicle lamp information, vehicle interior temperature information, vehicle interior humidity information, steering wheel rotation angle information, vehicle external illumination, pressure applied to an accelerator pedal, and pressure applied to a brake pedal. 
     The sensing unit  125  may further include, for example, an accelerator pedal sensor, a pressure sensor, an engine speed sensor, an Air Flow-rate Sensor (AFS), an Air Temperature Sensor (ATS), a Water Temperature Sensor (WTS), a Throttle Position Sensor (TPS), a Top Dead Center (TDC) sensor, and a Crank Angle Sensor (CAS). 
     The location information module  114  may be arranged as a sub-component of the sensing unit  125 . 
     The sensing unit  125  may include an object sensing unit capable of sensing an object around the vehicle  100 . Here, the object sensing unit may include a camera module, a radar, Lidar, or an ultrasonic sensor. In this case, the sensing unit  125  may sense a front object located at the front of the vehicle  100  or a rear object located at the rear of the vehicle  100  using the camera module, the radar, the Lidar, or the ultrasonic sensor. 
     In some implementations, the object sensing unit may be sorted as a constituent component of the driver assistance apparatus  400 . 
     The memory  130  is electrically connected to the controller  170 . The memory  130  may store basic data for each unit, control data for the operation control of the unit, and input/output data. The memory  130  may be any of various storage devices, such as a ROM, a RAM, an EPROM, a flash drive, and a hard drive. The memory  130  may store various data for the overall operation of the vehicle  100 , such as programs for the processing or control of the controller  170 . 
     The output unit  140  is configured to output information processed in the controller  170 . The output unit  140  may include a display device  141 , a sound output unit  142 , and a haptic output unit  143 . 
     The display device  141  may display various graphic objects. For example, the display device  141  may display vehicle associated information. Here, the vehicle associated information may include vehicle control information for the direct control of the vehicle  100  or driver assistance information to guide the driver&#39;s vehicle driving. In addition, the vehicle associated information may include vehicle state information that indicates the current state of the vehicle or vehicle traveling information regarding the traveling of the vehicle. 
     The display device  141  may include at least one selected from among a Liquid Crystal Display (LCD), a Thin Film Transistor LCD (TFT LCD), an Organic Light Emitting Diode (OLED), a flexible display, a  3 D display, and an e-ink display. 
     The display device  141  may configure an inter-layer structure with a touch sensor, or may be integrally formed with the touch sensor to implement a touchscreen. The touchscreen may function as the user input unit  124 , which provides an input interface between the vehicle  100  and the user, and also function to provide an output interface between the vehicle  100  and the user. In this case, the display device  141  may include a touch sensor for sensing a touch to the display device  141  so as to receive a control command in a touch manner. When a touch is input to the display device  141  as described above, the touch sensor may sense the touch and the controller  170  may generate a control command corresponding to the touch. Content input in a touch manner may be characters or numbers, or may be, for example, instructions in various modes or menu items that may be designated. 
     The display device  141  may include a cluster for allowing the driver to check vehicle state information or vehicle traveling information while driving the vehicle. The cluster may be located on a dashboard. In this case, the driver may check information displayed on the cluster while looking forward. 
     In some implementations, the display device  141  may be implemented as a Head Up display (HUD). When the display device  141  is implemented as a HUD, information may be output via a transparent display provided at the front windshield  10 . Alternatively, the display device  141  may include a projector module to output information via an image projected to the front windshield  10 . 
     In some implementations, the display device  141  may include a transparent display. In this case, the transparent display may be attached to the front windshield  10 . 
     The transparent display may display a prescribed screen with a prescribed transparency. In order to achieve the transparency, the transparent display may include at least one selected from among a transparent Thin Film Electroluminescent (TFEL) display, an Organic Light Emitting Diode (OLED) display, a transparent Liquid Crystal Display (LCD), a transmissive transparent display, and a transparent LED display. The transparency of the transparent display is adjustable. 
     In some implementations, the display device  141  may function as a navigation device. 
     The sound output unit  142  is configured to convert electrical signals from the controller  170  into audio signals and to output the audio signals. To this end, the sound output unit  142  may include, for example, a speaker. The sound output unit  142  may output sound corresponding to the operation of the user input unit  124 . 
     The haptic output unit  143  is configured to generate tactile output. For example, the haptic output unit  143  may operate to vibrate a steering wheel, a safety belt, or a seat so as to allow the user to recognize an output thereof. 
     The vehicle drive unit  150  may control the operation of various devices of the vehicle  100 . The vehicle drive unit  150  may include a power source drive unit  151 , a steering drive unit  152 , a brake drive unit  153 , a lamp drive unit  154 , an air conditioner drive unit  155 , a window drive unit  156 , an airbag drive unit  157 , a sunroof drive unit  158 , and a suspension drive unit  159 . 
     The power source drive unit  151  may perform electronic control for a power source inside the vehicle  100 . 
     For example, when a fossil fuel based engine is a power source, the power source drive unit  151  may perform electronic control for the engine. As such, the power source drive unit  151  may control, for example, an output torque of the engine. When the power source drive unit  151  is the engine, the power source drive unit  151  may limit the speed of the vehicle by controlling the output torque of the engine under the control of the controller  170 . 
     In another example, when an electric motor is a power source, the power source drive unit  151  may perform control for the motor. As such, the power source drive unit  151  may control, for example, the RPM and torque of the motor. 
     The steering drive unit  152  may perform electronic control for a steering apparatus inside the vehicle  100 . As such, the steering drive unit  152  may change the direction of travel of the vehicle  100 . 
     The brake drive unit  153  may perform electronic control of a brake apparatus inside the vehicle  100 . For example, the brake drive unit  153  may reduce the speed of the vehicle  100  by controlling the operation of brakes located at wheels. In another example, the brake drive unit  153  may adjust the direction of travel of the vehicle  100  leftward or rightward by differentiating the operation of respective brakes located at left and right wheels. 
     The lamp drive unit  154  may turn at least one lamp arranged inside and outside the vehicle  100  on or off. In addition, the lamp drive unit  154  may control, for example, the intensity and direction of light of the lamp. For example, the lamp drive unit  154  may perform control for a turn-signal lamp, a headlamp or a brake lamp. 
     The air conditioner drive unit  155  may perform the electronic control of an air conditioner inside the vehicle  100 . For example, when the interior temperature of the vehicle  100  is high, the air conditioner drive unit  155  may operate the air conditioner to supply cold air to the interior of the vehicle  100 . 
     The window drive unit  156  may perform the electronic control of a window apparatus inside the vehicle  100 . For example, the window drive unit  156  may control the opening or closing of left and right windows of the vehicle  100 . 
     The airbag drive unit  157  may perform the electronic control of an airbag apparatus inside the vehicle  100 . For example, the airbag drive unit  157  may control an airbag to be deployed in a dangerous situation. 
     The sunroof drive unit  158  may perform electronic control of a sunroof apparatus inside the vehicle  100 . For example, the sunroof drive unit  158  may control the opening or closing of a sunroof. 
     The suspension drive unit  159  may perform the electronic control for a suspension apparatus inside the vehicle  100 . For example, when the road surface is uneven, the suspension drive unit may control the suspension apparatus to reduce vibration of the vehicle  100 . 
     In some implementations, the vehicle drive unit  150  may include a chassis drive unit. Here, the chassis drive unit may include the steering drive unit  152 , the brake drive unit  153 , and the suspension drive unit  159 . 
     The controller  170  may control the overall operation of each unit inside the vehicle  100 . The controller  170  may be referred to as an Electronic Control Unit (ECU). 
     The controller  170  may be implemented in a hardware manner using at least one selected from among Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, and electric units for the implementation of other functions. 
     The interface unit  180  may serve as a passage for various kinds of external devices that are connected to the vehicle  100 . For example, the interface unit  180  may have a port that is connectable to a mobile terminal and may be connected to the mobile terminal via the port. In this case, the interface unit  180  may exchange data with the mobile terminal. 
     In some implementations, the interface unit  180  may serve as a passage for supplying electricity to a mobile terminal connected thereto. When the mobile terminal is electrically connected to the interface unit  180 , the interface unit  180  may provide electricity supplied from the power supply unit  190  to the mobile terminal under the control of the controller  170 . 
     The power supply unit  190  may supply power to operate the respective components under the control of the controller  170 . In particular, the power supply unit  190  may receive power from, for example, a battery inside the vehicle  100 . 
     The driver assistance apparatus  400  may assist the driver in driving the vehicle  100 . The driver assistance apparatus  400  may include the vehicle camera  200 . 
     In some implementations, the vehicle camera  200  may include a mono camera, such as the mono camera  200   a  illustrated in  FIGS. 3 to 5 , and/or may include a stereo camera, such as and the stereo camera  200   b  illustrated in  FIGS. 6 to 8 . 
     The vehicle camera  200  may include a variable lens  300 . The variable lens  300  may be controlled by the driver assistance apparatus to change the focal distance of the variable lens  300  and thereby change the focal distance of the camera  200 . For example, the variable lens  300  may be controlled to change the path of light passing through the camera  200  in order to change the focal distance. In some implementations, the variable lens  300  may be controlled to change the focal distance of the camera  200  based on detected surroundings of the vehicle, so as to provide a variable view of the surroundings that are appropriate for the situation. 
     In some implementations, the variable lens  300  may include a controllable liquid crystal layer. In such scenarios, the arrangement of liquid crystal molecules in the liquid crystal layer may be controlled by the driver assistance apparatus to selectively redirect light passing through the liquid crystal layer, thereby changing the focal distance of the camera  200 . 
     The following description will be given based on the driver assistance apparatus  400 , the vehicle camera  200 , and the variable lens  300 . The vehicle camera  200  may be referred to as a vehicle camera device. 
       FIG. 3  is a perspective view illustrating a vehicle camera in accordance with an implementation.  FIG. 4  is an exploded perspective view illustrating the vehicle camera in accordance with the implementation.  FIG. 5  is a cutaway side sectional view illustrating the vehicle camera taken along line A-B of  FIG. 3  in accordance with the implementation. 
     The vehicle camera  200  described below with reference to  FIGS. 3 to 5  is the mono camera  200   a.    
     The vehicle camera  200   a  may include at least one lens  211 , an image sensor  214 , the variable lens  300 , and at least one processor  470 . 
     In some implementations, the vehicle camera  200   a  may further include a processing board  220 , a light shield  230 , a heat radiation member  240 , and a housing  250  individually or in combinations thereof. 
     In some implementations, the housing  250  may include a first housing  251 , a second housing  252 , and a third housing  253 . 
     The at least one lens  211  may be fastened using a nut  212  so as to be seated in a hole  219  formed in a portion of the first housing  251  while being received in a lens housing  217 . 
     The image sensor  214  may include at least one photoelectric conversion element capable of converting optical signals into electrical signals. For example, the image sensor  214  may be a Charge-Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS). 
     The image sensor  214  may be located at an appropriate position on the exterior or interior of the vehicle  100  in order to acquire an image of the view outside or inside the vehicle  100 . 
     For example, the image sensor  214  may be located in the passenger compartment of the vehicle  100  so as to be close to the front windshield  10  in order to acquire an image of the view to the front of the vehicle  100 . Alternatively, the image sensor  214  may be located near a front bumper or a radiator grill. 
     For example, the image sensor  214  may be located in the passenger compartment of the vehicle  100  so as to be close to a rear windshield in order to acquire an image of the view to the rear of the vehicle  100 . Alternatively, the image sensor  214  may be located near a rear bumper, a trunk, or a tail gate. 
     For example, the image sensor  214  may be located in the passenger compartment of the vehicle  100  so as to be close to at least one side window in order to acquire an image of the view to the lateral side of the vehicle  100 . Alternatively, the image sensor  214  may be located near a side mirror, a fender, or a door. 
     The image sensor  214  may be located at the rear of the at least one lens  211  so as to acquire an image based on light introduced through the at least one lens  211 . For example, the image sensor  214  may be oriented perpendicular to the ground surface at a position spaced apart from the at least one lens  211  by a prescribed distance. 
     The variable lens  300  may be configured to be controlled to alter light to be introduced into the image sensor  214 . For example, the variable lens  300  may change the light to be introduced into the image sensor  214  so as to change the focal distance of the camera  200   a.    
     In some implementations, the variable lens  300  may include liquid crystals. The variable lens  300  may change the light that is to be introduced into the image sensor  214  based on the arrangement of liquid crystals. For example, the variable lens  300  may change the path of light to be introduced into the image sensor  214 , thereby changing the focal distance of the camera  200   a.    
     The variable lens  300  may be controlled by one or more processors of the driver assistance apparatus. For example, in the example of  FIG. 4 , the variable lens  300  may be controlled by the processor  470 . 
     Examples of the variable lens  300  will be described below in detail with reference to  FIG. 8  and the following drawings. 
     A module including the at least one lens  211 , the variable lens  300 , and the image sensor  214  may be referred to as an image acquisition module. In some implementations, the image acquisition module may be installed at the ceiling of the vehicle  100 . For example, the image acquisition module may be attached to the inner ceiling of the vehicle  100  with a prescribed connection member interposed therebetween. Positioning the image acquisition module on the inner ceiling of the vehicle  100  may, in some scenarios, provide an advantage of acquiring an image of a view outside the vehicle  100  from the highest position of the vehicle  100 . As such, in these scenarios, there may be an advantage of increasing the field of vision. 
     The processor  470  may be electrically connected to the image sensor  214  and the variable lens  300 . The processor  470  may perform computer processing on an image acquired via the image sensor  214 . The processor  470  may control the image sensor  214  and the variable lens  300 . 
     The processor  470  may be implemented, for example, using at least one selected from among Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, and electric units for the implementation of other functions. 
     The processor  470  may be mounted on the processing board  220 . 
     The processing board  220  may be configured so that the processor  470  and a memory  440  are mounted thereon. 
     The processing board  220  may be inclined in the overall length direction. For example, the processing board  220  may be oriented such that the front surface or the rear surface thereof faces the front windshield  10 . For example, the processing board  220  may be arranged parallel to the front windshield  10 . 
     The front windshield  10  included in the vehicle  100  is generally inclined from the bonnet to the roof of the vehicle  100  at a prescribed angle relative to the ground surface. In this case, when the processing board  220  is inclined in the overall length direction, the vehicle camera  200   a  may have a smaller size than when the processing board  220  is oriented vertically or horizontally. In some scenarios, the vehicle camera  200   a  having a reduced size may provide an advantage of increasing the available space inside the vehicle  100  in proportion to the reduction in the size of the vehicle camera  200   a.    
     A plurality of elements or electronic components may be mounted on the processing board  220 . In such scenarios, heat may be generated due to the elements or components included in the processing board  220 . 
     The processing board  220  may be spaced apart from the image sensor  214 . Spacing the processing board  220  apart from the image sensor  214  may, in some scenarios, mitigate heat generated from the processing board  220  from having a negative effect on the performance of the image sensor  214 . 
     The processing board  220  may be located at a particular position so as to mitigate heat generated in the processing board  220  from having an effect on the image sensor  214 . For example, the processing board  220  may be located underneath the image sensor  214 . Alternatively, the processing board  220  may be located at the front of the image sensor  214 . 
     One or more memories  440  may be mounted on the processing board  220 . The memories  440  may store images acquired via the image sensor  214 , various application data, data for the control of the processor  470 , or data processed by the processor  470 . In some scenarios, the memories  440  may be a source of heat generation, in addition to the processor  470 . Arranging the processor  470  at the center of the processing board  220  may allow the memories  440  to be arranged around the processor  470 . For example, the memories  440  may be arranged to surround the periphery of the processor  470 . In this case, the processor  470  and the memories  440 , which are heat generation elements, may be located at the farthest positions from the image sensor  214 . 
     The processor  470  may be electrically connected to the controller  170 . The processor  470  may be controlled by the controller  170 . 
     The light shield  230  may be located at the front of the at least one lens  211 . The light shield  230  may prevent light that is not necessary for image acquisition from being introduced into the at least one lens  211 . For example, the light shield  230  may block light reflected from, for example, the windshield  10  or the dashboard of the vehicle  100 . In addition, the light shield  230  may block light generated from an undesired light source. 
     The light shield  230  may have a screen shape. For example, the light shield  230  may take the form of a lower screen. 
     In some implementations, the shape of the light shield  230  may be changed depending on the vehicle model. For example, the light shield  230  may have a shape corresponding to the model of the vehicle to which the vehicle camera  200   a  is installed because the curvature of the windshield and the angle between the windshield and the ground surface may be different for different vehicle models. To this end, the light shield  230  may have a separable structure. 
     The heat radiation member  240  may be located at the rear of the image sensor  214 . The heat radiation member  240  may come into contact with the image sensor  214  or an image sensor board on which the image sensor  214  is mounted. The heat radiation member  240  may handle the heat from the image sensor  214 . 
     As described above, the image sensor  214  is sensitive to heat. The heat radiation member  240  may be located between the image sensor  214  and the third housing  253 . The heat radiation member  240  may be located so as to come into contact with the image sensor  214  and the third housing  253 . In this case, the heat radiation member  240  may radiate heat through the third housing  253 . 
     For example, the heat radiation member  240  may be any one of a thermal pad and thermal grease. 
     The housing  250  may include the lens housing  217 , the first housing  251 , the second housing  252 , and the third housing  253 . 
     The lens housing  217  may receive at least one lens  211 , and may protect the at least one lens  211  from external shocks. 
     The first housing  251  may be formed so as to surround the image sensor  214 . The first housing  251  may have the hole  219 . The at least one lens  211  received in the lens housing  217  may be connected to the image sensor  214  while being seated in the hole  219 . 
     In some implementations, the first housing  251  may have a thickness that gradually increases with decreasing distance towards the image sensor  214 . As such, the first housing  251  may be thicker in a region near the image sensor  214 . In some scenarios, this configuration may help mitigate deterioration in performance of the image sensor  214  due to heat by providing a portion of the first housing  251  close to the image sensor  214  being thicker than the remaining portion of the first housing  251 . For example, the first housing  251  may be formed via die casting. 
     In some implementations, the thickness of the first housing  251  may be greater than the thickness of the third housing  253 . In such scenarios, the thicker housing may transfer heat more slowly. Therefore, when the thickness of the first housing  251  is greater than the thickness of the third housing  253 , heat generated inside the vehicle camera  200   a  may be radiated outward through the third housing  253 , rather than through the first housing  251 , which is located near the front windshield  10  and may thus have difficulty in radiating heat. 
     In some implementations, the lens housing  217  and the first housing  251  may be integrally formed with each other. 
     The second housing  252  may be located at the front end of the processing board  220 . The second housing  252  may be fastened to the first housing  251  and the third housing  253  via prescribed fasteners. 
     The second housing  252  may include an attachment member to which the light shield  230  may be attached. The light shield  230  may be attached to the second housing  252  via the attachment member. 
     The first and second housings  252  and  253  may be formed of a synthetic resin material. 
     The third housing  253  may be fastened to the first housing  251  and the second housing  252  via prescribed fasteners. In some implementations, the first to third housings  251 ,  252  and  253  may be integrally formed with one another. 
     The third housing  253  may be formed so as to surround the processing board  220 . The third housing  253  may be located at the rear end or the lower end of the processing board  220 . The third housing  253  may be formed of a thermally conductive material. For example, the third housing  253  may be formed of a metal such as aluminum. The third housing  253  formed of a thermally conductive material may achieve efficient heat radiation. 
     When the first and second housings  251  and  252  are formed of a synthetic resin material and the third housing  253  is formed of a thermally conductive material, heat inside the vehicle camera  200   a  may be radiated from the third housing  253 , rather than the first and second housings  251  and  252 . For example, when the vehicle camera  200   a  is mounted on the windshield  10 , the first and second housings  251  and  252  are located close to the windshield  10 , and therefore the heat may not be radiated through the first and second housings  251  and  252 . In this case, the heat may be efficiently radiated through the third housing  253 . 
     Implementing the third housing  253  as being formed of aluminum may, in some scenarios, be advantageous to protect components located in the third housing  253  (e.g. the image sensor  214  and the processor  470 ) from Electro Magnetic Compatibility (EMC) and Electrostatic Discharge (ESC). 
     The third housing  253  may come into contact with the processing board  220 . In this case, the third housing  253  may effectively radiate heat outward by transferring the heat through the portion thereof in contact with the processing board  220 . 
     The third housing  253  may further include a heat radiator  291 . For example, the heat radiator  291  may include at least one selected from among a heat sink, a heat radiation fin, a thermal pad, and thermal grease. 
     The heat radiator  291  may outwardly radiate heat generated inside the vehicle camera  200   a . For example, the heat radiator  291  may be located between the processing board  220  and the third housing  253 . The heat radiator  291  may come into contact with the processing board  220  and the third housing  253  so as to outwardly radiate heat generated in the processing board  220 . 
     The third housing  253  may further include an air discharge hole. The air discharge hole is a hole for discharging high-temperature air inside the vehicle camera  200   a  to the outside of the vehicle camera  200   a . An air flow structure may be provided inside the vehicle camera  200   a  so as to be connected to the air discharge hole. The air discharge hole may guide the high-temperature air inside the vehicle camera  200   a  to the air discharge hole. 
     The vehicle camera  200   a  may further include a damp-proof member. The damp-proof member may take the form of a patch and may be attached to the air discharge hole. The damp-proof member may be a Gore-Tex damp-proof member. The damp-proof member may discharge moisture inside the vehicle camera  200   a  to the outside. In addition, the damp-proof member may prevent moisture outside the vehicle camera  200   a  from being introduced into the vehicle camera  200   a.    
       FIG. 6  is a perspective view illustrating a vehicle camera in accordance with an implementation.  FIG. 7  is an exploded perspective view illustrating the vehicle camera in accordance with the implementation.  FIG. 8  is a cutaway side sectional view illustrating the vehicle camera taken along line C-D of  FIG. 6  in accordance with the implementation. 
     The vehicle camera  200  described below with reference to  FIGS. 6 to 8  is the stereo camera  200   b.    
     The description given in relation to the mono camera  200   a  with reference to  FIGS. 3 to 5  may be wholly applied to the stereo camera  200   b . For example, each of first and second cameras included in the stereo camera  200   b  may be the camera described above with reference to  FIGS. 3 to 5 . 
     As shown in the example of  FIGS. 6 and 7 , the stereo camera  200   b  may include at least one lens, such as a first lens  211   a  and a second lens  211   b . The stereo camera  200   b  may also include a first image sensor  214   a , a second image sensor  214   b , a left variable lens  300 L, a right variable lens  300 R, and a processor  470   a.    
     In some implementations, the vehicle camera  200   b  may further include a processing board  220   a , a first light shield  230   a , a second light shield  230   b , and a housing  250   a  individually or in combinations thereof. 
     In some implementations, the housing  250   a  may include a first lens housing  217   a , a second lens housing  217   b , a first housing  251   a , a second housing  252   a , and a third housing  253   a.    
     In these examples, the description given in relation to the at least one lens  211  with reference to  FIGS. 3 to 5  may be applied to the first lens  211   a  and the second lens  211   b.    
     Furthermore, in these examples, the description given in relation to the image sensor  214  with reference to  FIGS. 3 to 5  may be applied to the first image sensor  214   a  and the second image sensor  214   b.    
     The description in relation to the variable lens  300  with reference to  FIGS. 3 to 5  may be applied to the left variable lens  300 L and the right variable lens  300 R. 
     In particular, the left variable lens  300 L may include a first liquid crystal layer, and may change the light to be introduced into the first image sensor  214   a  based on the arrangement of liquid crystal molecules included in the first liquid crystal layer, which depends on the voltage applied thereto. The left variable lens  300 L may be referred to as a first variable lens. 
     The right variable lens  300 R may include a second liquid crystal layer, and may change the light to be introduced into the second image sensor  214   b  based on the arrangement of liquid crystal molecules included in the second liquid crystal layer, which depends on the voltage applied thereto. The right variable lens  300 R may be referred to as a second variable lens. 
     A module including the first lens  211   a , the first image sensor  214   a , and the left variable lens  300 L may be referred to as a first image acquisition module. In addition, a module including the second lens  211   b , the second image sensor  214   b , and the right variable lens  300 R may be referred to as a second image acquisition module. 
     The processor  470   a  may be electrically connected to the first image sensor  214   a , the second image sensor  214   b , the left variable lens  300 L, and the right variable lens  300 R. The processor  470   a  may perform computer processing on images acquired via the first image sensor  214   a  and the second image sensor  214   b . The processor  470  may form a disparity map or perform disparity calculation based on the images acquired via the first image sensor  214   a  and the second image sensor  214   b.    
     The processor  470   a  may be implemented using at least one selected from among Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, and electric units for the implementation of other functions. 
     The processor  470   a  may be mounted on the processing board  220   a.    
     The description given in relation to the processing board  220  with reference to  FIGS. 3 to 5  may be applied to the processing board  220   a.    
     The description given in relation to the light shield  230  with reference to  FIGS. 3 to 5  may be applied to the first light shield  230   a  and the second light shield  230   b.    
     The description given in relation to the lens housing  217  with reference to  FIGS. 3 to 5  may be applied to the first lens housing  217   a  and the second lens housing  217   b.    
     The description given in relation to the first housing  251  with reference to  FIGS. 3 to 5  may be applied to the first housing  251   a.    
     The description given in relation to the second housing  252  with reference to  FIGS. 3 to 5  may be applied to the second housing  252   a.    
     The description given in relation to the third housing  253  with reference to  FIGS. 3 to 5  may be applied to the third housing  253   a.    
       FIG. 9  is an enlarged cutaway side sectional view illustrating portion CR 1  of  FIG. 5  or portion CR 2  of  FIG. 8 . 
     Referring to  FIG. 9 , the vehicle camera  200  may include the image sensor  214  and the variable lens  300 . 
     The image sensor  214  may include a CCD or CMOS as described above. 
     The image sensor  214  may be located at the rear of the variable lens  300 . 
     The variable lens  300  may be located at the front of the image sensor  214 . 
     The variable lens  300  may include a liquid crystal layer. The variable lens  300  may change the light to be introduced to the image sensor  214  based on the arrangement of liquid crystal molecules included in the liquid crystal layer, which depends on the voltage applied thereto, under the control of the processor  470 . 
     For example, the variable lens  300  may refract the light to be introduced to the image sensor  214 . In this case, the variable lens  300  may change the focal distance. The variable lens may perform various lens functions under the control of the processor  470 . 
     For example, the variable lens  300  may include a wetting lens, a Graded Refractive Index (GRIN) lens or a Fresnel lens. 
     The wetting lens may change the introduced light by varying a polar material using the potential difference of the electricity applied to the lens. 
     The GRIN lens or the Fresnel lens may include a liquid crystal layer and may change the introduced light based on the arrangement of liquid crystals included in the liquid crystal layer, which depends on the application of electricity thereto. 
     The variable lens  300  may be configured to be slidably moved in the left-right direction (e.g. in the overall width direction). The vehicle camera  200  may include an actuator (e.g., actuator  401  in  FIG. 19 ) and a drive power transmission unit. 
     For example, the actuator (e.g., actuator  401  in  FIG. 19 ) may include a motor. The drive power transmission unit may include at least one gear. 
     The actuator (e.g., actuator  401  in  FIG. 19 ) may generate drive power under the control of the processor  470 . The drive power generated in the actuator (e.g., actuator  401  in  FIG. 19 ) may be transmitted to the variable lens  300  via the drive power transmission unit through conversion from rotation to linear movement. The variable lens  300  may be slidably moved in the left-right direction (e.g., in the overall width direction) upon receiving drive power. 
     The variable lens  300  may be configured to be slidably moved in the front-rear direction (e.g., in the overall length direction). The vehicle camera  200  may include the actuator (e.g., actuator  401  in  FIG. 19 ) and the drive power transmission unit. 
     For example, the actuator (e.g., actuator  401  in  FIG. 19 ) may include a motor. The drive power transmission unit may include at least one gear. 
     The actuator (e.g., actuator  401  in  FIG. 19 ) may generate drive power under the control of the processor  470 . The drive power generated in the actuator (e.g., actuator  401  in  FIG. 19 ) may be transmitted to the variable lens  300  via the drive power transmission unit through conversion from rotation to linear movement. The variable lens  300  may be slidably moved in the front-rear direction (e.g., in the overall length direction) upon receiving drive power. 
     In this way, the variable lens  300  may cope with blurring by sliding in the front-rear direction as the focal distance is changed. 
     The variable lens  300  may be configured to be rotatably moved. The vehicle camera  200  may include the actuator (e.g., actuator  401  in  FIG. 19 ) and the drive power transmission unit. 
     For example, the actuator (e.g., actuator  401  in  FIG. 19 ) may include a motor. The drive power transmission unit may include at least one gear. 
     The actuator (e.g., actuator  401  in  FIG. 19 ) may generate drive power under the control of the processor  470 . The drive power generated in the actuator (e.g., actuator  401  in  FIG. 19 ) may be transmitted to the variable lens  300  via the drive power transmission unit. The variable lens  300  may be rotated and moved forward upon receiving the drive power. 
     When the variable lens  300  is configured to be slidably or rotatably moved as described above, the variable lens  300  may be used as needed, and may not be used by being slidably or rotatably moved when it is not necessary. 
     In some implementations, the vehicle camera  200  may further include at least one lens  211 . The example of  FIG. 9  illustrates the at least one  211  including four lenses, a first lens  211   a , a second lens  211   b , a third lens  211   c  and a fourth lens  211   d . However, the number of lenses is not limited thereto and any suitable number of lenses in the at least one lens  211  may be implemented. 
     The at least one lens  211  may be located between the variable lens  300  and the image sensor  214 . The at least one lens  211  may refract introduced light. The light refracted via the at least one lens  211  may be introduced to the image sensor  214 . 
     In some implementations, the vehicle camera  200  may further include the housing  250 . The housing  250  may include the lens housing  217 , the first housing  251 , the second housing  252 , and the third housing  253 . 
     The housing  250  may define the external appearance of the vehicle camera  200 , and may receive the respective components of the vehicle camera  200  including the image sensor  214  and the variable lens  300 . 
     The housing  250  may include a holder  1010 . Although  FIG. 9  illustrates the holder  1010  as being formed on the lens housing  217 , the holder  1010  may be formed on the first housing  251  in some implementations. 
     The holder  1010  may support the variable lens  300 . The holder  1010  may include an upper holder  1010 U for supporting the upper end of the variable lens  300  and a lower holder  1010 L for supporting the lower end of the variable lens  300 . 
     In some implementations, the vehicle camera  200  may further include a heating element. The heating element may supply heat to the variable lens  300  under the control of the processor  470 . In some implementations, the heating element may include one or more hot wires. 
     In some scenarios, liquid crystals may be sensitive to the surrounding temperature. For example, variable lenses that include liquid crystals may be vulnerable to the surrounding temperature, and particularly to low temperatures. In some implementations, the variable lens  300  included in the vehicle camera  200  may be configured in consideration of thermal properties of liquid crystals so as to cope with driving conditions in cold temperatures, such as during the winter or driving in very cold areas. In implementation in which the vehicle camera  200  includes a heating element as in the present implementation, the variable lens  300  may be operated even in such low-temperature driving situations. 
     In some implementations, the heating element may include one or more hot wires that may be referred to as a heat supply unit. 
     The heating element may be formed inside the holder  1010 . For example, the heating element may be formed inside at least one of the upper holder  1010 U and the lower holder  1010 L. 
     The holder  1010  and the heating element formed inside the holder  1010  will be described below with reference to  FIGS. 10A to 10C . 
       FIGS. 10A to 11  are enlarged side views illustrating portion HS of  FIG. 9 , which are referenced to describe various implementations of the holder and a heating element provided inside the holder. 
     Although the upper holder  1010 U will be described by way of example with reference to  FIGS. 10A to 11 , a description related to the upper holder  1010 U may be applied to the lower holder  1010 L because the lower holder  1010 L has the same function and configuration as those of the upper holder  1010 U except the difference in the portion thereof for supporting the variable lens  300 . 
     Referring to  FIGS. 10A to 11 , the holder  1010  may include a slot  1020 . 
     The slot  1020  may receive a portion of the variable lens  300 . For example, the slot  1020  included in the upper holder  1010 U may receive an upper portion of the variable lens  300 . The slot  1020  included in the lower holder  1010 L may receive a lower portion of the variable lens  300 . 
     A heating element may be formed inside the slot  1020 . For example, as shown in  FIG. 10A , hot wires  1051  and  1052  may be formed inside the slot  1020 . 
     In some implementations, the hot wires  1051  and  1052  may be spaced apart from the variable lens  300 . As such, the spacing of the hot wires  1051  and  1052  apart from the variable lens  300  may help mitigate damage to the variable lens  300  as compared to scenarios where the hot wires  1051  and  1052  come into contact with the variable lens  300 . Heat generated from the hot wires  1051  and  1052  may be transferred to the variable lens  300  via radiation. 
     In some implementations, as illustrated in the example of  FIG. 10B , a heating element, such as hot wire  1053 , may come into contact with at least a portion of the rim of the variable lens  300 . In this case, heat generated from the hot wire  1053  may be transferred to the variable lens  300  via conduction, which may provide efficient and direct transfer of heat. 
     In some implementations, the holder  1010  may include a first fixing portion  1031  and a second fixing portion  1032 . 
     The first fixing portion  1031  may support a first surface  301  of the variable lens  300 . The first surface  301  may be the surface facing the front side of the vehicle. 
     The first fixing portion  1031  may include a first separated portion  1031   a  and a first contact portion  1031   b.    
     The first separated portion  1031   a  may extend upward or downward from a base  1025 . The first separated portion  1031   a  may be spaced apart from the variable lens  300 , rather than coming into contact with the variable lens  300 . A cavity may be formed between the first separated portion  1031   a  and the variable lens  300 . 
     The first contact portion  1031   b  may extend from the first separated portion  1031   a  toward the rear side of the vehicle  100 . The first contact portion  1031   b  may come into contact with a portion of the first surface  301  of the variable lens  300 . The first contact portion  1031   b  may support the variable lens  300  in conjunction with a second contact portion  1032   b , so as to fix the variable lens  300 . 
     The second fixing portion  1032  may support a second surface  302  of the variable lens  300 . The second surface  302  may be the surface facing the rear side of the vehicle. 
     The second fixing portion  1032  may include a second separated portion  1032   a  and the second contact portion  1032   b.    
     The second separated portion  1032   a  may extend upward or downward from the base  1025 . The second separated portion  1032   a  may be spaced apart from the variable lens  300 , rather than coming into contact with the variable lens  300 . A cavity may be formed between the second separated portion  1032   a  and the variable lens  300 . 
     The second contact portion  1032   b  may extend from the second separated portion  1032   a  toward the front side of the vehicle  100 . The second contact portion  1032   b  may be symmetrical to the first contact portion  1031   b  about the variable lens  300 . The second contact portion  1032   b  may support the variable lens  300  in conjunction with the first contact portion  1031   b , so as to fix the variable lens  300 . 
     The slot  1020  may be formed between the first fixing portion  1031  and the second fixing portion  1032 . 
     A heating element may be provided. For example, the first hot wire  1051  and the second hot wire  1052  may be provided. 
     The first hot wire  1051  may be formed on a portion of the first fixing portion  1031 . 
     The first hot wire  1051  may be located between the first fixing portion  1031  and the variable lens  300 . For example, the first hot wire  1051  may be located between the first fixing portion  1031  and the first surface  301  of the variable lens  300 . 
     The first hot wire  1051  may be spaced apart from the variable lens  300 . For example, the first hot wire  1051  may be spaced apart from the first surface  301  of the variable lens  300 . 
     The second hot wire  1052  may be located between the second fixing portion  1032  and the variable lens  300 . For example, the second hot wire  1052  may be located between the second fixing portion  1032  and the second surface  302  of the variable lens  300 . 
     The second hot wire  1052  may be spaced apart from the variable lens  300 . For example, the second hot wire  1052  may be spaced apart from the second surface  302  of the variable lens  300 . 
     In some implementations, as illustrated in  FIG. 11 , the first fixing portion  1031  may include a first ridged portion  1061 . For example, the first contact portion  1031   b  may include the first ridged portion  1061 . 
     The first ridged portion  1061  may come into contact with at least a portion of the first surface  301 . For example, the first ridged portion  1061  may include at least one ridge and at least one furrow. Here, the ridge may protrude toward the variable lens  300  so as to come into contact with the first surface  301  of the variable lens  300 . The furrow may be indented away from the variable lens  300  so as to be spaced apart from the first surface  301  of the variable lens  300 . 
     Through the provision of the ridge and the furrow as described above, it is possible to prevent damage to the variable lens  300  when supporting and fixing the variable lens  300 . For example, although shocks may be applied to the vehicle camera  200  depending on the road conditions when the vehicle  100  is being driven, it is possible to reduce the application of shocks to the variable lens  300  upon the occurrence of such shocks. 
     The first hot wire  1051  may be formed on the first ridged portion  1061 . For example, the first hot wire  1051  may be formed on the protrusion or in the furrow included in the first ridged portion  1061 . 
     When the first hot wire  1051  is formed on the ridge, the first hot wire  1051  may come into contact with the first surface  301  of the variable lens  300  so that heat is transferred to the variable lens  300  via conduction. In this case, the efficient and direct transfer of heat is possible. 
     When the first hot wire  1051  is formed in the furrow, the first hot wire  1051  may be spaced apart from the first surface  301  of the variable lens  300  so that heat is transferred to the variable lens  300  via radiation. In this case, it is possible to prevent damage to the variable lens  300 . 
     The second fixing portion  1032  may include a second ridged portion  1062 . For example, the second contact portion  1032   b  may include the second ridged portion  1062 . 
     The second ridged portion  1062  may come into contact with at least a portion of the second surface  302 . For example, the second ridged portion  1062  may include at least one ridge and at least one furrow. Here, the ridge may protrude toward the variable lens  300  so as to come into contact with the second surface  302  of the variable lens  300 . The furrow may be indented away from the variable lens  300  so as to be spaced apart from the second surface  302  of the variable lens  300 . 
     Through the provision of the ridge and the furrow as described above, it is possible to prevent damage to the variable lens  300  when supporting and fixing the variable lens  300 . For example, although shocks may be applied to the vehicle camera  200  depending on the road conditions when the vehicle  100  is being driven, it is possible to reduce the application of shocks to the variable lens  300  upon the occurrence of such shocks. 
     The second hot wire  1052  may be formed on the second ridged portion  1062 . For example, the second hot wire  1052  may be formed on the protrusion or in the furrow included in the second ridged portion  1062 . 
     When the second hot wire  1052  is formed on the ridge, the second hot wire  1052  may come into contact with the second surface  302  of the variable lens  300  so that heat is transferred to the variable lens  300  via conduction. In this case, the efficient and direct transfer of heat is possible. 
     When the second hot wire  1052  is formed in the furrow, the second hot wire  1052  may be spaced apart from the second surface  302  of the variable lens  300  so that heat is transferred to the variable lens  300  via radiation. In this case, it is possible to prevent damage to the variable lens  300 . 
       FIG. 12  is a view referenced to describe the variable lens in accordance with an implementation. 
     Referring to  FIG. 12 , the variable lens  300  may include a first substrate  1210 , a second substrate  1220 , and a liquid crystal layer  1230 . 
     The first substrate  1210  may include a first base substrate  1211 , a plurality of first electrodes  1212 , and an insulator film  1213 . 
     The first electrodes  1212  may be formed on the first base substrate  1211 . The first electrodes  1212  are spaced apart from one another by a prescribed distance. A voltage may be applied to the first electrodes  1212  under the control of the processor  470 . For example, different levels of voltage may be respectively applied to each of the first electrodes  1212  under the control of the processor  470 . 
     In some implementations, the first electrodes  1212  may be transparent electrodes. For example, the first electrodes may be transparent Indium Tin Oxide (ITO) electrodes. When the first electrodes  1212  are transparent electrodes, the field of vision of the vehicle camera  200  may be achieved by preventing the electrodes from blocking the field of vision. 
     The insulator film  1213  may be formed on the first base substrate  1211  so as to cover the first electrodes  1212 . 
     The second substrate  1220  may be disposed so as to face the first substrate  1210 . The second substrate  1220  may include a second base substrate  1221  and a second electrode  1222 . 
     The second electrode  1222  may be formed on the second base substrate  1221 . The second electrode  1222  may be disposed so as to face the first electrodes  1212 . A voltage may be applied to the second electrode  1222  under the control of the processor  470 . A constant level of voltage may be applied to the second electrode  1222  under the control of the processor  470 . 
     In some implementations, the second electrode  1222  may be a transparent electrode. For example, the second electrode  1222  may be a transparent ITO electrode. When the second electrode  1222  is a transparent electrode, the field of vision of the vehicle camera  200  may be achieved by preventing the electrodes from blocking the field of vision. 
     The liquid crystal layer  1230  may be disposed between the first substrate  1210  and the second substrate  1220 . The liquid crystal layer  1230  may include a plurality of liquid crystal molecules  1231 . The liquid crystal molecules  1231  may be driven from the horizontal direction to the vertical direction at a prescribed angle corresponding to the magnitude of a voltage applied thereto. The focal point of the variable lens  300  may be changed due to the prescribed angle of the liquid crystal molecules  1231  under the control of the processor  470 . 
     The variable lens  300  may further include a first transparent plate and a second transparent plate. The first transparent plate may be disposed outside the first substrate  1210 . The second transparent plate may be disposed outside the second substrate  1220 . The transparent plate may be referred to as glass. 
       FIG. 13  is a view referenced to describe the first substrate in accordance with an implementation. 
       FIG. 13  illustrates the first substrate  1210  in accordance with an implementation, which is viewed from the top side thereof. 
     Referring to  FIG. 13 , the first substrate (e.g., first substrate  1210  in  FIG. 12 ) may include a plurality of first electrodes  1212   a  to  1212   i . The first electrodes  1212   a  to  1212   i  may be spaced apart from one another by a prescribed distance. The first electrodes  1212   a  to  1212   i  may be arranged in the up-down direction or in the left-right direction. Here, the up-down direction may refer to the overall height direction or the vertical direction. The left-right direction may refer to the overall width direction or the horizontal direction. 
       FIG. 13  illustrates the first electrodes  1212   a  to  1212   i  arranged so as to extend in the up-down direction. 
     When the first electrodes  1212   a  to  1212   i  are arranged so as to extend in the up-down direction as described above, the Field Of View (FOV) in the left-right direction may be widened. 
     As the number of first electrodes  1212   a  to  1212   i  is increased, the FOV in the left-right direction may be gradually widened. 
     The variable lens  300  may further include a drive unit. The drive unit may apply a voltage to the respective first electrodes  1212   a  to  1212   i  or the second electrode  1222 . The drive unit is electrically connected to the processor  470 . The drive unit may be connected to the processor  470  via an FPCB or a cable. 
     In some implementations, a plurality of drive units may be provided. For example, the drive units may include a first drive unit  1310  and a second drive unit. 
     The first drive unit  1310  may include an Integrated Circuit (IC). The first drive unit  1310  may apply a voltage to the first electrodes  1212   a  to  1212   i  upon receiving a signal from the processor  470 . The first drive unit  1310  may apply a constant level of voltage to the first electrodes  1212   a  to  1212   i . Alternatively, the first drive unit  1310  may apply different levels of voltage to each of the first electrodes  1212   a  to  1212   i.    
     The second drive unit may include an IC. The second drive unit may apply a voltage to the second electrode  1222  upon receiving a signal from the processor  470 . The second drive unit may apply a constant level of voltage to the second electrode  1222 . 
     The first substrate  1210  may include a heating element, such as hot wire  1310 ′. The hot wire  1310 ′ may be disposed on the first base substrate  1211 . For example, the hot wire  1310 ′ may be disposed along the rim of the first base substrate  1211 . With this arrangement of the hot wire  1310 ′, the field of vision of the vehicle camera  200  may be achieved without blocking the field of vision due to the hot wire  1310 ′. 
     The hot wire  1310 ′ may supply heat to the variable lens  300 . For example, the hot wire  1310 ′ may supply heat to the liquid crystal layer  1230 . 
     In some implementations, the second substrate  1220  may include a heating element, such as a hot wire. The hot wire may be disposed on the second base substrate  1221 . 
       FIGS. 14A to 14C  are views referenced to describe an operation in which different levels of voltage are respectively applied to each of the first electrodes in accordance with an implementation. 
     Referring to  FIG. 14A , the processor  470  may control the levels of voltage  1410  respectively applied to each of the first electrodes  1212   a  to  1212   i  by controlling the first drive unit (e.g., first drive unit  1310  in  FIG. 13 ). The arrangement  1420  of the liquid crystal molecules  1231  included in the liquid crystal layer  1230  may be converted so as to correspond to the levels of voltage applied to the first electrodes  1212   a  to  1212   i.    
     As illustrated in the example of  FIG. 14B , the processor  470  may control the first drive unit  1310  so that a constant level of voltage  1430  is applied to the first electrodes  1212   a  to  1212   i.    
     In this case, the liquid crystal molecules  1231  included in the liquid crystal layer  1230  may have the arrangement  1440  for transmitting light introduced from the outside, rather than refracting the light. The arrangement of the liquid crystal molecules  1231  illustrated in  FIG. 14B  is merely given by way of example, and the arrangement may be changed according to the properties of the liquid crystals. 
     In this case, the variable lens  300  may have a reduced FOV and an increased focal distance, thus functioning as a telephoto lens. In this case, the variable lens  300  may be used to detect, and track an object located a long distance away from the vehicle  100 . 
     As exemplarily illustrated in  FIG. 14C , the processor  470  may control the first drive unit  1310  so that different levels of voltage  1450  are applied to the first electrodes  1212   a  to  1212   i . For example, the processor  470  may control the first drive unit  1310  such that a higher level of voltage is applied to center electrodes  1212   e  and  1212   f  among the first electrodes  1212   a  to  1212   i  than that applied to outer peripheral electrodes  1212   a  and  1212   j.    
     In this case, the liquid crystal molecules  1231  included in the liquid crystal layer  1230  may have an arrangement  1460  for refracting some or all of the light introduced from the outside. The arrangement of the liquid crystal molecules  1231  illustrated in  FIG. 14C  is merely given by way of example, and the arrangement may be changed according to the kind of liquid crystals. 
     In this case, the variable lens  300  may have an increased FOV and a reduced focal distance, thus functioning as a wide-angle lens. In this case, the variable lens  300  may be used to detect and track an object located a short distance away from the vehicle  100 . In this case, the processor  470  may control the first drive unit  1310  so that the levels of voltage applied to the electrodes are symmetrical on the left side and the right side about the center electrodes  1212   e  and  1212   f.    
     In some implementations, the processor  470  may change the FOV or the focal distance by controlling the levels of voltage of the first electrodes  1212   a  to  1212   i.    
     In some implementations, the processor  470  may control the first drive unit  1310  so that the levels of voltage applied to the electrodes are symmetrical on the left side and the right side about the center electrodes  1212   e  and  1212   f . In this case, the processor  470  may change the focal point of the variable lens  300  based on a Point of Interest (POI). 
     The processor  470  may perform computer processing on an image acquired via the image sensor  214 . 
       FIG. 15  is a view referenced to describe the arrangement of the first electrodes in the left-right direction in accordance with an implementation. 
     Referring to  FIG. 15 , the first substrate (e.g., first substrate  1210  in  FIG. 12 ) may include the first electrodes  1212   a  to  1212   i . Here, the first electrodes  1212   a  to  1212   i  may be arranged so as to extend in the left-right direction. 
     When the first electrodes  1212   a  to  1212   i  are arranged so as to extend in the left-right direction as described above, the Field Of View (FOV) in the up-down direction may be widened. 
     As the number of first electrodes  1212   a  to  1212   i  is increased, the FOV in the up-down direction may be gradually widened. 
       FIG. 16  is a view referenced to describe the arrangement of the first electrodes in the left-right direction and the up-down direction in accordance with an implementation. 
     Referring to  FIG. 16 , the first electrodes may be arranged so as to extend in the up-down direction and the left-right direction. 
     The first substrate  1210  may include the first electrodes  1212  and a plurality of capacitors  1610 . Here, the first electrodes  1212  may be arranged so as to extend in the left-right direction and the up-down direction. 
     The capacitors  1610  may be located at respective intersections of the electrodes arranged so as to extend in the up-down direction and the electrodes arranged so as to extend in the left-right direction. The capacitors  1610  may prevent voltage drop that may occur at the intersections, thereby allowing a voltage to be applied to the respective first electrodes  1212  under the control of the controller  170 . 
     Thin Film Transistors (TFTs) may be located between the intersections and the capacitors  1610 . The TFTs may prevent reversed current. 
       FIGS. 17 and 18  are views referenced to describe a vehicle camera including a plurality of variable lenses in accordance with an implementation. 
       FIG. 17  is a cutaway side view of the vehicle camera taken along line A-B of  FIG. 3  or line C-D of  FIG. 6  in accordance with an implementation. 
       FIG. 18  is an enlarged cutaway side view of portion CR 3  of  FIG. 18 . 
     The vehicle camera of  FIGS. 17 and 18  differs from the vehicle camera described above with reference to  FIGS. 1 to 17  in that it includes a first variable lens  300   a  and a second variable lens  300   b . The above description, made with reference to  FIGS. 1 to 16 , may be applied to the other configurations of the vehicle camera  200  of  FIGS. 17 and 18 , excluding the provision of the variable lenses  300   a  and  300   b.    
     In addition, the above description given in relation to the variable lens  300  with reference to  FIGS. 1 to 16  may be applied to each of the first variable lens  300   a  and the second variable lens  300   b.    
     The vehicle camera  200  may include the image sensor  214 , the first variable lens  300   a , the second variable lens  300   b , and the processor  470 . 
     The first variable lens  300   a  may include a first liquid crystal layer, and may change light to be introduced to the image sensor  214  based on the arrangement of liquid crystal molecules included in the first liquid crystal layer. The first variable lens  300   a  may be located at the front side of the image sensor  214  and the second variable lens  300   b . The first variable lens  300   a  may change the light introduced from the outside. 
     The first variable lens  300   a  may include a first substrate, a second substrate, and the first liquid crystal layer. 
     The description given in relation to the variable lens  300  with reference to  FIG. 12  may be applied to the first variable lens  300   a.    
     In particular, a plurality of electrodes may be disposed on the first substrate included in the first variable lens  300   a  so as to be spaced apart from one another. 
     In some implementations, the electrodes provided on the first substrate may be arranged so as to extend in the up-down direction. The number of electrodes provided on the first substrate may be greater than the number of electrodes provided on a third substrate. When the electrodes are arranged so as to extend in the up-down direction, an FOV in the left-right direction is widened. In an image acquired by the vehicle camera  200 , information in the left-right direction may be more useful than information in the up-down direction. When the number of electrodes provided on the third substrate is greater than the number of electrodes provided on the first substrate, a greater number of pieces of information may be acquired in the up-down direction than that in the left-right direction. 
     In some implementations, the electrodes provided on the first substrate may be arranged so as to extend in the left-right direction. 
     The second variable lens  300   b  may include a second liquid crystal layer, and may change light to be introduced to the image sensor  214  based on the arrangement of liquid crystal molecules included in the second liquid crystal layer, which depends on the voltage applied thereto. The second variable lens  300   b  may be located at the front side of the image sensor  214 . The second variable lens  300   a  may change the light introduced through the first variable lens  300   a.    
     The second variable lens  300   b  may include a third substrate, a fourth substrate, and the second liquid crystal layer. 
     The description given in relation to the variable lens  300  with reference to  FIG. 12  may be applied to the second variable lens  300   b.    
     In particular, a plurality of electrodes may be disposed on the third substrate included in the second variable lens  300   b  so as to be spaced apart from one another. 
     In some implementations, the electrodes provided on the third substrate may be arranged so as to extend in the left-right direction. 
     In some implementations, the electrodes provided on the third substrate may be arranged so as to extend in the up-down direction. The number of electrodes provided on the third substrate may be greater than the number of electrodes provided on the first substrate. When the electrodes are arranged so as to extend in the up-down direction, an FOV in the left-right direction is widened. In an image acquired by the vehicle camera  200 , information in the left-right direction may be more useful than information in the up-down direction. When the number of electrodes provided on the third substrate is greater than the number of electrodes provided on the first substrate, a greater number of pieces of information may be acquired in the up-down direction than that in the left-right direction. 
     The image sensor  214  may receive the light introduced through the first variable lens  300   a  and the second variable lens  300   b.    
       FIG. 19  is a block diagram of the driver assistance apparatus  400  in accordance with an implementation. 
     Referring to  FIG. 19 , the driver assistance apparatus  400  may include the vehicle camera  200 , the processor  470 , an interface unit  430 , and the memory  440 . 
     In some implementations, the driver assistance apparatus  400  may further include a communication unit  410 , an input unit  420 , an output unit  450 , and a power supply unit  490  individually or in combinations thereof. 
     In some implementations, unlike the illustration of  FIG. 19 , the processor  470 , the interface unit  430 , and the memory  440  may be sub-components of the camera  200 . In this case, the vehicle camera  200  may function as the driver assistance apparatus  400 . 
     The vehicle camera  200  may be mounted on a portion of the vehicle  100  and may acquire an image of the view outside or inside the vehicle  100 . 
     For example, the vehicle camera  200  may be located in the passenger compartment of the vehicle  100  so as to be close to the front windshield  10  in order to acquire an image of the view in front of the vehicle  100 . Alternatively, the vehicle camera  200  may be located near a front bumper or a radiator grill. 
     For example, the vehicle camera  200  may be located in the passenger compartment of the vehicle  100  so as to be close to a rear windshield in order to acquire an image of the view at the rear of the vehicle  100 . Alternatively, the vehicle camera  200  may be located near a rear bumper, a trunk, or a tail gate. 
     For example, the vehicle camera  200  may be located in the passenger compartment of the vehicle  100  so as to be close to at least one side window in order to acquire an image of the view at the lateral side of the vehicle  100 . Alternatively, the vehicle camera  200  may be located near a side mirror, a fender, or a door. 
     For example, the vehicle camera  200  may be located in the passenger compartment of the vehicle  100  on the front windshield  10 , a dashboard, a cockpit module, or a rear windshield so as to face the passenger compartment in order to acquire an image of the passenger compartment of the vehicle  100 . 
     The vehicle camera  200  may include the image sensor  214 , the variable lens  300 , and the actuator  401 . 
     The image sensor  214  has been described above with reference to  FIGS. 1 to 19 . 
     The variable lens  300  may change light to be introduced to the image sensor  214 . As such, the variable lens  300  may change the focal distance of the camera  200  by changing the light to be introduced to the image sensor  214 . 
     In some implementations, the variable lens  300  may include liquid crystals. The variable lens  300  may change the light to be introduced to the image sensor  214  based on the arrangement of liquid crystals. For example, the variable lens  300  may change the focal distance by changing the path of light to be introduced to the image sensor  214  by way of the variable lens  300 . 
     The variable lens  300  may be controlled by the processor  470 . For example, the variable lens  300  may be controlled by the processor  470  to change the focal distance of the camera  200  based on various types of information regarding the driving state of the vehicle. As such, the driver assistance apparatus may variably control the focal distance of the camera  200  to adapt to different driving conditions, thereby providing appropriate views of the vehicle surroundings based on the particular driving condition. 
     The variable lens  300  has been described above with reference to  FIGS. 1 to 19 . 
     The actuator  401  may provide drive power to move the variable lens  300  or the image sensor  214 . The actuator  401  may include a motor. 
     The actuator  401  may provide drive power for the slidable movement or rotatable movement of the variable lens  300 . The drive power generated in the actuator  401  may be provided to the variable lens  300  through a drive power transmission unit. 
     For example, the variable lens  300  may be slidably moved in the left-right direction (or the overall width direction), in the front-rear direction (or the overall length direction), and in the up-down direction (or the overall height direction) upon receiving the drive power from the actuator  401 . 
     For example, the variable lens  300  may be rotatably moved upon receiving the drive power from the actuator  401 . 
     In some implementations, the actuator  401  may provide drive power for the slidable movement of the image sensor  214 . The drive power generated in the actuator  401  may be provided to the image sensor  214  through a drive power transmission unit. 
     For example, the image sensor  214  may be slidably moved in the front-rear direction (or the overall length direction) upon receiving the drive power from the actuator  401 . 
     In some implementations, the vehicle camera  200  may be a stereo camera (e.g., stereo camera  200   b  in  FIGS. 6 to 8 ). 
     When the vehicle camera  200  is the stereo camera  200   b , the vehicle camera  200  may include a first camera, a second camera, and the processor  470 . 
     The first camera may acquire a first image. 
     The first camera may include a first image sensor (e.g., first image sensor  214   a  in  FIGS. 6 to 8 ), and a left variable lens (e.g., left variable lens  300 L in  FIGS. 6 to 8 ). 
     The left variable lens  300 L may include a first liquid crystal layer, and may change light to be introduced to the first image sensor  214   a  based on the arrangement of liquid crystal molecules included in the first liquid layer, which depends on the voltage applied thereto. The left variable lens  300 L may be referred to as a first variable lens. 
     The second camera may acquire a second image. 
     The second camera may include a second image sensor (e.g., second image sensor  214   b  in  FIGS. 6 to 8 ), and a right variable lens (e.g., right variable lens  300 R in  FIGS. 6 to 8 ). 
     The right variable lens  300 R may include a second liquid crystal layer, and may change light to be introduced to the second image sensor  214   b  based on the arrangement of liquid crystal molecules included in the first liquid layer, which depends on the voltage applied thereto. The right variable lens  300 R may be referred to as a second variable lens. 
     The interface unit  430  may receive various signals, information, or data. The interface unit  430  may transmit signals, information, or data processed or produced in the processor  470 . 
     To this end, the interface unit  430  may perform data communication with, for example, the controller  170  inside the vehicle  100 , the vehicle display device  141 , the sensing unit  125 , and the vehicle drive unit  150  in a wired or wireless communication manner. 
     The interface unit  430  may receive driving information. Here, the driving information may include speed information, vehicle steering information, turn-signal information, and predetermined path information. 
     The interface unit  430  may receive sensor information from the controller  170  or the sensing unit  125 . 
     Here, the sensor information may include at least one selected from among vehicle travel direction information, vehicle location information (GPS information), vehicle angle information, vehicle speed information, vehicle steering information, vehicle acceleration information, vehicle tilt information, vehicle forward/reverse movement information, battery information, fuel information, tire information, vehicle lamp information (e.g. turn-signal information), vehicle interior temperature information, vehicle interior humidity information, and information regarding whether it rains. 
     The sensor information may be acquired from, for example, a heading sensor, a yaw sensor, a gyro sensor, a position module, a vehicle forward/reverse movement sensor, a wheel sensor, a vehicle speed sensor, a steering angle sensor, a vehicle body gradient sensor, a battery sensor, a fuel sensor, a tire sensor, a steering sensor based on the rotation of a steering wheel, a vehicle interior temperature sensor, a vehicle interior humidity sensor, and a rain sensor. In some implementations, the position module may include a GPS module for receiving GPS information. 
     The interface unit  430  may receive navigation information via data communication with the controller  170 , the vehicle display device  141 , or a separate navigation apparatus. Here, the navigation information may include set destination information, destination based routing information, map information related to vehicle driving, and vehicle&#39;s current location information. For example, the navigation information may include information regarding a vehicle&#39;s location on a road. 
     The interface unit  430  may provide the controller  170  or the vehicle drive unit  150  with a signal. Here, the signal may be a control signal. 
     For example, the interface unit  430  may perform communication with the power source drive unit  151  for controlling a power source. The interface unit  430  may provide the power source drive unit  151  with a signal produced in the processor  470 . 
     For example, the interface unit  430  may perform communication with the brake drive unit  153  for controlling a brake. The interface unit  430  may provide the brake drive unit  153  with a signal produced in the processor  470 . 
     For example, the interface unit  430  may perform communication with the steering drive unit  152  for controlling a steering apparatus. The interface unit  430  may provide the steering drive unit  152  with a signal produced in the processor  470 . 
     The memory  130  may store various data for the overall operation of the driver assistance apparatus  400 , such as programs for the processing or control of the processor  470 . 
     The memory  440  may be any one of various hardware storage devices, such as a ROM, a RAM, an EPROM, a flash drive, and a hard drive. In some implementations, the memory  440  may be a sub-component of the processor  470 . 
     The processor  470  may be electrically connected to each unit of the driver assistance apparatus  400 . 
     The processor  470  may control the overall operation of each unit included in the driver assistance apparatus  400 . 
     The processor  470  may process an image acquired via the vehicle camera  200 . 
     The processor  470  may control the drive unit (e.g., first drive unit  1310  in  FIG. 13 ) included in the variable lens  300 , and thus control the arrangement of liquid crystal molecules (e.g., liquid crystal molecules  1231  in  FIG. 12 ) included in the liquid crystal layer (e.g., liquid crystal layer  1230  in  FIG. 12 ), thereby changing the focal distance of the variable lens  300 . 
     As described further below, the processor  470  may receive various types of information and change the focal distance of the variable lens  300  based on the received information. 
     For example, the processor  470  may receive driving information via the interface unit  430 . The processor  470  may change the focal distance of the variable lens  300  based on the received driving information. 
     The driving information may include driving speed information. The processor  470  may receive driving speed information from the controller (e.g., controller  170  in  FIG. 2 ) or the sensing unit (e.g., sensing unit  125  in  FIG. 2 ) of the vehicle  100  via the interface unit  430 . The sensing unit (e.g., sensing unit  125  in  FIG. 2 ) may include a vehicle speed sensor. 
     As a particular example, the processor  470  may change the focal distance of the variable lens  300  based on driving speed information. 
     The processor  470  may gradually increase the focal distance of the variable lens  300  as the driving speed is gradually increased. When the focal distance is gradually increased, the FOV of the vehicle camera  200  is gradually reduced, thus becoming suitable for remote image capture. In this case, the vehicle camera  200  may serve as a telephoto camera. When a driver drives the vehicle  100  by focusing at a long distance, rather than a short distance, as the driving speed is gradually increased, the driver may appropriately respond to an occurring situation. 
     The processor  470  may gradually reduce the focal distance of the variable lens  300  as the driving speed is gradually reduced. When the focal distance is gradually reduced, the FOV of the vehicle camera  200  is gradually increased, thus becoming suitable for short-distance image capture. In this case, the vehicle camera  200  may serve as a wide-angle camera. When a driver drives the vehicle  100  by focusing at a short distance with an increased FOV, rather than a long distance, as the driving speed is gradually reduced, the driver may appropriately respond to an occurring situation. 
     As another example, the processor  470  may receive vehicle steering information or turn-signal information via the interface unit  430 . The processor  470  may change the focal distance of the variable lens  300  based on the received steering information or turn-signal information. 
     The driving information may include vehicle steering information or turn-signal information. The processor  470  may receive the vehicle steering information or turn-signal information from the controller (e.g., controller  170  in  FIG. 2 ) or the sensing unit (e.g., sensing unit  125  in FIG.  2 ) of the vehicle  100  via the interface unit  430 . 
     In some implementations, the sensing unit (e.g., sensing unit  125  in  FIG. 2 ) may include a steering sensor. When steering is input via a steering apparatus, the steering sensor may produce steering information. The processor  470  may receive the produced steering information via the interface unit  430 . 
     In some implementations, when a turn-signal input is received via a turn-signal input apparatus, the processor  470  may receive turn-signal information via the interface unit  430 . 
     The processor  470  may reduce the focal distance of the variable lens  300  when a steering value of a reference value or more to the left side or the right side of the direction of travel is received as steering information. 
     Pedestrian collision accidents occur at a high frequency when the vehicle  100  turns to the left or to the right. This is because the driver has difficulty in acquiring many pieces of information within a short time after being confronted with a new environment when the vehicle  100  turns to the left or to the right. In such a situation, the vehicle camera  200  may be used as a wide-angle camera by reducing the focal distance of the variable lens  300  and increasing the FOV of the vehicle camera  200 . When the vehicle camera  200  is used as such a wide-angle camera, it is possible to acquire information regarding a greater number of objects that are located a short distance away and to prevent the occurrence of accidents. 
     As another example, the processor  470  may receive a predetermined path information of the vehicle  100  via the interface unit  430 . The processor  470  may change the focal distance of the variable lens  300  based on the received path information. 
     The driving information may include, for example, predetermined path information of the vehicle  100 . The processor  470  may receive predetermined path information of the vehicle  100  from the vehicle display device  141  or a separate navigation apparatus via the interface unit  430 . 
     In some implementations, the driving speed, acceleration, or deceleration of the vehicle  100  may be controlled based on the predetermined path information. For example, when the vehicle  100  is an autonomous vehicle, the vehicle  100  may be driven based on the predetermined path information. The processor  470  may change the focal distance of the variable lens  300  based on the predetermined path information, thereby acquiring information suitable for the driving of the vehicle  100  and providing the vehicle  100  or the driver with the acquired information. 
     As another example, the processor  470  may receive V2X information via the interface unit  430 . The processor  470  may change the focal distance of the variable lens  300  based on the V2X information. 
     The V2X information may be information regarding the situation around the vehicle  100  received via the V2X communication module  116 . The driving speed, acceleration, or deceleration of the vehicle  100  may be controlled based on the V2X information. In particular, when the vehicle  100  is an autonomous vehicle, the vehicle  100  may be driven based on the V2X information. The processor  470  may change the focal distance of the variable lens  300  based on the V2X information, thereby acquiring information suitable for the driving of the vehicle  100  and providing the vehicle  100  or the driver with the acquired information. 
     The processor  470  may receive an input signal via the input unit  420 . The processor  470  may change the focal distance of the variable lens  300  based on the received input signal. 
     As another example, the processor  470  may control the Power-On/Off of an ADAS based on the input signal received via the input unit  420 . The processor  470  may change the focal distance of the variable lens  300  so as to suit the ADAS, which is in the On state based on the input signal. 
     The Advanced Driver Assistance System (ADAS) may include an Autonomous Emergency Braking (AEB) system, an Adaptive Cruise Control (ACC) system, a Cross Traffic Alert (CTA) system, a Lane Change Assistant (LCA) system, a Forward Collision Warning (FCW) system, a Lane Departure Warning (LDW) system, a Lane Keeping Assistant (LKA) system, a Speed Assistant System (SAS), a Traffic Sign Recognition (TSR) system, a High Beam Assistant (HBA) system, a Blind Spot Detection (BSD) system, an Autonomous Emergency Steering (AES) system, a Curve Speed Warning System (CSWS), a Smart Parking Assistant System (SPAS), a Traffic Jam Assistant (TJA) system, and an Around View Monitoring (AVM) system. 
     For example, the ACC system, SAS, and CSWS may utilize information regarding an object that is located a relatively long distance away. The processor  470  may increase the focal distance of the variable lens  300  upon receiving an input signal for turning on the ACC system, SAS system, or the CSWS. 
     For example, the CTA, AEB, FCW, TSR, HBA, BSD, AES, and TJA systems may utilize information regarding an object that is located a relatively long distance away. The processor  470  may reduce the focal distance of the variable lens  300  upon receiving an input signal for turning on the CTA, AEB, FCW, TSR, HBA, BSD, AES, or TJA system. 
     As another example, the processor  470  may detect an object from an image acquired via the vehicle camera  200 . The object that is detected may include a wide range of objects, including but not limited to vehicles and persons as well as, more generally, roadways and intersections and other configurations of the surrounding environment around the vehicle. The processor  470  may change the focal distance of the variable lens  300  based on the detected object. 
     As a specific example, the processor  470  may change the focal distance of the variable lens  300  based on the distance to the object or the position of the object. 
     The processor  470  may change the focal distance of the camera  200  so as to capture an appropriate image of an object  2925  based on the distance to or position of the object. 
     The processor  470  may calculate the distance to the object based on the acquired image. An operation of calculating the distance to the object will be described below with reference to  FIGS. 20A to 20C . 
     The processor  470  may calculate the position of the object based on the acquired image. For example, the processor  470  may calculate the position of the object relative to the vehicle  100  based on pixels corresponding to the position of the object in the image. 
     The processor  470  may gradually increase the focal distance of the variable lens  300  as the distance to the object is gradually increased. 
     The processor  470  may detect an object and track the detected object. When the distance to the object is gradually increased, the processor  470  may gradually increase the focal distance of the variable lens  300  for object tracking. Thereby, the processor  470  may maintain object tracking by adjusting the focal distance of the variable lens  300 . 
     The processor  470  may gradually reduce the focal distance of the variable lens  300  as the distance to the object is gradually reduced. 
     The processor  470  may detect an object and track the detected object. When the distance to the object is gradually reduced, the processor  470  may gradually reduce the focal distance of the variable lens  300  for object tracking. Thereby, the processor  470  may maintain object tracking by adjusting the focal distance of the variable lens  300 . 
     The processor  470  may, based on object position information, alter the focal distance of the variable lens  300  to thereby change the Region of Interest (ROI) of an image. 
     For example, when an object is detected in an image, the processor  470  may change the ROI of the image so as to clearly display the detected object. For example, the processor  470  may adjust the focal distance of the variable lens  300  so that the detected object is focused on. 
     The processor  470  may adjust the distance between the variable lens  300  and the image sensor  214  by controlling the actuator  401  so as to correspond to the changed focal distance of the variable lens  300 . 
     For example, when the focal distance of the variable lens  300  is increased, the processor  470  may move the variable lens  300  in the front-rear direction (or in the overall length direction) by controlling the actuator  401 , thereby controlling the distance between the variable lens  300  and the image sensor  214  so as to be increased. 
     For example, when the focal distance of the variable lens  300  is reduced, the processor  470  may move the variable lens  300  in the front-rear direction (or in the overall length direction) by controlling the actuator  401 , thereby controlling the distance between the variable lens  300  and the image sensor  214  so as to be reduced. 
     In some implementations, the processor  470  may adjust the distance between the variable lens  300  and the image sensor  214  by moving the image sensor  214 . 
     The adjustment of the distance between the variable lens  300  and the image sensor  214  may prevent the blurring of an image. 
     As another example, the processor  470  may detect an intersection as an object. When the intersection is detected as an object, the processor  470  may reduce the focal distance of the variable lens  300  based on the detected intersection. 
     When the vehicle  100  is passing through an intersection, the driver may be wary about an object (e.g. another vehicle) that is located in the direction crossing the direction of travel of the vehicle  100 . In such scenarios, for example at the intersection, an image having an increased FOV may be acquired in order to detect, for example, a vehicle or a pedestrian that violates a traffic signal. 
     Therefore, in some implementations, upon detection of an intersection as described above, the driver assistance apparatus may be configured to reduce the focal distance of the variable lens  300  to acquire an image having an increased FOV and detect an object within a wider range. This may help prevent an accident at the intersection by providing a better view of the relevant portions of the surroundings of the vehicle. 
     When the vehicle camera  200  is the stereo camera  200   b , the vehicle camera  200  may include a first camera, a second camera, and the processor  470 . 
     The processor  470  may change the focal distance of the left variable lens  300 L by controlling the arrangement of liquid crystal molecules included in the first liquid crystal layer. In addition, the processor  470  may change the focal distance of the right variable lens  300 R by controlling the arrangement of liquid crystal molecules included in the second liquid crystal layer. 
     The processor  470  may change the focal distance of the left variable lens  300 L and the focal distance of the right variable lens  300 R in different manners. In some implementations, the processor  470  may coordinate the changing of the focal distance of the left variable lens  300 L with the changing the focal distance of the right variable lens  300 R. 
     For example, the processor  470  may increase the focal distance of the left variable lens  300 L, thereby allowing the first camera to be used as a long-distance camera. In addition, the processor  470  may reduce the focal distance of the right variable lens  300 R, thereby allowing the second camera to be used as a short-distance camera. 
     The processor  470  may process a first image acquired via the first camera, and may process a second image acquired via the second camera. The focal distances of the first camera and the second camera may differ from each other. 
     The processor  470  may perform process binning on the first image. The processor  470  may perform cropping on the second image. 
     The processor  470  may acquire a stereo image based on the binned first image and the cropped second image. 
     The processor  470  may perform disparity calculation based on the acquired stereo image. 
     The processor  470  may detect an object based on the first image. The processor  470  may change the focal distance of the left variable lens  300 L or the right variable lens  300 R based on the detected object. For example, the processor  470  may change the focal distances of the left variable lens  300 L and the right variable lens  300 R so as to coincide with each other so that the object is focused on. 
     The processor  470  may acquire a stereo image based on a first image and a second image, which are acquired after the focal distances are changed. 
     The communication unit  410  may exchange data with another device located inside or outside the vehicle  100  in a wireless manner. Here, the other device may be a mobile terminal, a server, or another vehicle. 
     For example, the communication unit  410  may exchange data with a mobile terminal of the driver in a wireless manner. Various wireless data communication protocols, such as Bluetooth, Wi-Fi, Wi-Fi direct, APiX, and NFC, may be used. 
     For example, the communication unit  410  may receive weather information and road traffic state information, such as Transport Protocol Expert Group (TPEG) information, from the mobile terminal or the server. 
     When a user enters the vehicle  100 , the mobile terminal of the user may pair with the driver assistance apparatus  400  automatically or as the user executes an application. 
     The communication unit  410  may receive traffic light change information from an external server. Here, the external server may be a server located in a traffic control center. 
     The input unit  420  may receive user input. The input unit  420  may include a mechanical input device, a touch input device, a voice input device, or a wireless input device. 
     The mechanical input device may include, for example, a button, a jog-wheel, or a switch. 
     The touch input device may include at least one touch sensor. The touch input device may be configured as a touchscreen. 
     The voice input device may include a microphone for converting the user&#39;s voice into electrical signals. 
     The wireless input device may receive wireless user input via a key from the outside of the vehicle  100 . 
     The input unit  420  may receive user input for opening or closing a door included in the vehicle  100 . 
     The output unit  450  may output data or information processed in the processor  470  under the control of the processor  470 . 
     The output unit  450  may include a display unit  451  and a sound output unit  452 . 
     The display unit  451  may display information processed in the processor  470 . The display unit  451  may display an image related to the operation of the driver assistance apparatus  400 . For the display of the image, the display unit  451  may include a cluster or a Head Up Display (HUD) provided on the inner front surface of the vehicle  100 . In scenarios where the display unit  451  is the HUD, the display unit  451  may include a projector module for projecting an image to the front windshield  10  or a combiner. 
     The sound output unit  452  may output sound to the outside based on an audio signal processed in the processor  470 . To this end, the sound output unit  452  may include at least one speaker. 
     The power supply unit  490  may supply power required to operate the respective components under the control of the processor  470 . The power supply unit  490  may receive power from, for example, a battery inside the vehicle  100 . 
       FIGS. 20A to 21  are schematic diagrams illustrating the variable lens in order to describe an operation of calculating the distance to an object using the variable lens in accordance with an implementation. 
     The processor  470  may detect an object from an image acquired via the vehicle camera  200 . The processor  470  may track the object detected in the image by varying the focal distance of the variable lens  300  and analyzing resulting variations in the object in the image. As such, the processor  470  may calculate the distance to the object based on variation in the object, by varying the focal distance. 
     For example, the processor  470  may calculate the distance to the object based on a detected blurring of the object in the image as the focal distance of the variable lens  300  is changed. 
     For example, the processor  470  may calculate the distance to the object based on variation in the size of the object in the image as the focal distance of the variable lens  300  is changed. 
     For example, the processor  470  may acquire two images as the focal distance of the variable lens  300  is changed. The processor  470  may produce a stereo image based on the acquired two images. The processor  470  may perform disparity calculation based on the stereo image. The processor  470  may calculate the distance to the object based on disparity calculation. 
       FIG. 20A  illustrates the case where the focal distance of the variable lens  300  is in the first state, and  FIG. 20B  illustrates the case where the focal distance of the variable lens  300  is in the second state. In particular,  FIGS. 20A and 20B  illustrate the case where the variable lens  300  is close to the image sensor  214 . 
     Referring to  FIG. 20A , the Gaussian lens formula may be applied to the variable lens  300 .
 
1/ L= 1/ O+ 1/ I   Equation 1:
 
     Here, “L” is the distance to the variable lens  300  to the image sensor  214 , “O” is the distance to the variable lens  300  to an object  2010 , and “I” is the distance at which an image is formed via the variable lens  300 . 
     The processor  470  may calculate the distance O from the variable lens  300  to the object  2010  based on the distance I at which the image is formed via the variable lens  300  and the distance L from the variable lens  300  to the image sensor  214 . This distance detection method may be referred to as a pinhole model method. 
     Referring to  FIG. 20B , when the focal distance of the variable lens  300  is changed under the control of the processor  470 , the size of an object in an image acquired via the vehicle camera  200  may be changed. 
     In this case, the processor  470  may detect the distance to the object using the Gaussian lens formula and variation in the size of the object. 
     Because the processor  470  may calculate the distance I at which the image is formed via the variable lens  300  based on the size of the object, and may know the distance L between the variable lens  300  and the image sensor  214 , the processor  470  may calculate the distance O between the variable lens  300  and the object  2010 . Here, the distance between the variable lens  300  and the object  2010  may be defined as the distance between the vehicle  100  and the object  2010 . 
     In some implementations, the processor  470  may calculate the distance to the object based on the blurring of the image based on the changed focal point of the variable lens  300 . 
     In the state in which the focal distance of the variable lens  300  is tuned to suit the prescribed object  2010 , the processor  470  may change the focal distance of the variable lens  300 . In this case, blurring may occur at the rim of the object  2010  in the image acquired via the vehicle camera  200 . Here, the blurring may have a Gaussian form. 
     The processor  470  may calculate the distance to the object based on the degree of blurring that depends on variation in the focal distance of the variable lens  300 . For example, the processor  470  may calculate the distance to the object by measuring the extent of Gaussian blur. 
       FIG. 21  illustrates an operation of calculating the distance to the object using disparity. 
     Referring to  FIG. 21 , the processor  470  may change the focal distance of the variable lens  300  to take the first state VLFL. For example, the processor  470  may change the focal distance of the variable lens  300  so as to focus on the area to the left side based on the direction of travel of the vehicle at the first distance ahead of the vehicle. 
     The processor  470  may acquire a first image IM 1  when the focal distance of the variable lens  300  is in the first state VLFL. 
     The processor  470  may change the focal distance of the variable lens  300  to take the second state VLFR. For example, the processor  470  may change the focal distance of the variable lens  300  so as to focus on the area to the right side, based on the direction of travel of the vehicle, at the first distance ahead of the vehicle. 
     The processor  470  may acquire a second image IM 2  when the focal distance of the variable lens  300  is in the second state VLFR. 
     The processor  470  may acquire the first image IM 1  and the second image IM 2  within a very short time. For example, the processor  470  may acquire the first image IM 1  and the second image IM 2  at about the same time. 
     The processor  470  may produce a stereo image SIM based on the first image IM 1  and the second image IM 2 . The processor  470  may perform disparity calculation based on the stereo image SIM. The processor  470  may detect the distance to the object based on disparity calculation. 
       FIG. 22  is a flowchart referenced to describe an operation of the driver assistance apparatus in accordance with an implementation. 
       FIGS. 23A and 23B  are views referenced to describe an operation of changing the focal distance of the variable lens based on a driving speed in accordance with an implementation. 
       FIG. 24  is a view referenced to describe an operation of changing the focal distance of the variable lens based on steering information or turn-signal information in accordance with an implementation. 
       FIG. 25  is a view referenced to describe an operation of changing the focal distance of the variable lens based on predetermined path information in accordance with an implementation. 
     Referring to  FIG. 22 , the processor  470  may receive driving information via the interface unit  430  (S 2210 ). 
     The driving information may include driving speed information, steering information, turn-signal information, and predetermined path information. 
     The sensing unit  125  of the vehicle  100  may include a vehicle speed sensor. The vehicle speed sensor may produce driving speed information. The processor  470  may receive the driving speed information via the interface unit  430  from the controller (e.g., controller  170  in  FIG. 2 ) or the sensing unit (e.g., sensing unit  125  in  FIG. 2 ) of the vehicle. 
     The sensing unit  125  of the vehicle  100  may include a steering sensor. When steering is input via a steering apparatus, the steering sensor may produce steering information. The processor  470  may receive the steering information via the interface unit  430  from the controller (e.g., controller  170  in  FIG. 2 ) or the sensing unit (e.g., sensing unit  125  in  FIG. 2 ) of the vehicle. 
     The vehicle  100  may receive a turn-signal input via the input unit (e.g., input unit  420  in  FIG. 19 ). The processor  470  may receive turn-signal information via the interface unit  430  from the input unit (e.g., input unit  420  in  FIG. 19 ), the controller (e.g., controller  170  in  FIG. 2 ), or the lamp drive unit (e.g., lamp drive unit  154  in  FIG. 2 ) of the vehicle. 
     The processor  470  may receive predetermined path information of the vehicle via the interface unit  430  from the vehicle display device  141  or a navigation apparatus. The predetermined path information of the vehicle may be stored in a memory of the vehicle display device  141  or a memory of the navigation apparatus. 
     The processor  470  may change the focal distance of the variable lens  300  based on driving information (S 2220 ). 
     The processor  470  may change the focal distance of the variable lens  300  based on a driving speed. 
     For example, the processor  470  may change the focal distance of the variable lens  300  in proportion to the driving speed. 
     For example, the processor  470  may change the focal distance of the variable lens  300  so as to correspond to variation in driving speed. 
     As exemplarily illustrated in  FIG. 23A , the processor  470  may gradually increase the focal distance of the variable lens  300  as the driving speed is increased. 
     An image  2310  may be acquired via the vehicle camera  200  by changing the focal distance of the variable lens  300  based on the driving speed when the vehicle  100  drives at 30 km/h. 
     In addition, an image  2320  may be acquired via the vehicle camera  200  by changing the focal distance of the variable lens  300  based on the driving speed when the vehicle  100  drives at 110 km/h. 
     When the driving speed of the vehicle  100  is gradually increased from 30 km/h to 110 km/h, the processor  470  may gradually increase the focal distance of the variable lens  300  so as to correspond to variation in driving speed. 
     When the focal distance is increased, the vehicle camera  200  may detect an object that is located a long distance away, although the FOV thereof is reduced. Generally, in the case of high-speed driving, information regarding an object that is located a long distance away may be useful. 
     As exemplarily illustrated in  FIG. 23B , the processor  470  may gradually reduce the focal distance of the variable lens  300  as the driving speed is gradually reduced. 
     An image  2330  may be acquired via the vehicle camera  200  by changing the focal distance of the variable lens  300  based on the driving speed when the vehicle  100  drives at 110 km/h. 
     In addition, an image  2340  may be acquired via the vehicle camera  200  by changing the focal distance of the variable lens  300  based on the driving speed when the vehicle  100  drives at 30 km/h. 
     When the driving speed of the vehicle  100  is gradually reduced from 110 km/h to 30 km/h, the processor  470  may gradually reduce the focal distance of the variable lens  300  so as to correspond to variation in driving speed. 
     When the focal distance is reduced, the vehicle camera  200  may be difficult to detect an object that is located a long distance away, but may have an increased FOV. Generally, in the case of low-speed driving, information regarding an object that is detected within an increased range may be useful. 
     The processor  470  may change the focal distance of the variable lens  300  based on steering information or turn-signal information. 
     The processor  470  may reduce the focal distance of the variable lens  300  when a steering value of a reference value or more to the left side or the right side of the direction of travel is received as steering information. 
     As exemplarily illustrated in  FIG. 24 , when the vehicle  100  turns to the left or to the right, detecting objects over a wide field of vision is required in order to prevent an accident. Because the driver is confronted with a new environment, which is different from an existing driving path, immediately after turned to the left or to the right at a low speed, a greater number of pieces of object information need to be provided within a short-distance range of the vehicle  100 . 
     An image  2410  may be acquired via the vehicle camera  200  immediately before making a right turn. 
     An image  2420  may be acquired via the vehicle camera  200  by changing the focal distance of the variable lens  300  based on the steering information or the turn-signal information immediately after right turn. 
     When the vehicle  100  turns to the left or to the right, the processor  470  may reduce the focal distance of the variable lens  300 . 
     The processor  470  may change the focal distance of the variable lens  300  based on predetermined path information. 
     The path information may include information regarding the high-speed driving path (e.g. expressway driving) or the low-speed driving path (e.g. city driving). The path information may include right-turn path information or left-turn path information of the vehicle  100 . 
     The processor  470  may change the focal distance of the variable lens  300  based on the high-speed driving path, the low-speed driving path, the right-turn path or the left-turn path. 
     As exemplarily illustrated in  FIG. 25 , when the predetermined path information includes information regarding left-turn path  2505  or right-turn path and the vehicle  100  drives along the left-turn path  2505  or right-turn path, the processor  470  may reduce the focal distance of the variable lens  300 . 
     An image  2510  may be acquired via the vehicle camera  200  immediately before the vehicle enters the left-turn path  2505  during driving based on the path information. 
     An image  2520  may be acquired via the vehicle camera  200  immediately after the vehicle enters the left-turn path  2505  during driving based on the path information. 
     Alternatively, when the vehicle  100  moves from the high-speed road to the low-speed road based on predetermined path information, the processor  470  may reduce the focal distance of the variable lens  300 . 
     Alternatively, when the vehicle  100  moves from the low-speed road to the high-speed road based on predetermined path information, the processor  470  may increase the focal distance of the variable lens  300 . 
     Alternatively, when the vehicle  100  enters a curve section based on predetermined path information, the processor  470  may reduce the focal distance of the variable lens  300  compared to in the case of straight section driving. 
     As described above, changing the focal distance of the variable lens  300  based on predetermined path information may provide the driver or the vehicle with information suitable for responding to the situation, thereby preventing an accident. 
       FIG. 26  is a flowchart referenced to describe an operation of the driver assistance apparatus in accordance with an implementation. 
       FIG. 27  is a view referenced to describe an operation of changing the focal distance of the variable lens based on an input signal in accordance with an implementation. 
     Referring to  FIG. 26 , the processor  470  may receive an input signal via the input unit  420  (S 2610 ). 
     The driver assistance apparatus  400  may provide various functions of an Advanced Driver Assistance System (ADAS). Some or all of the ADAS functions may be turned on or off in response to user input received via the input unit  420 . 
     The processor  470  may change the focal distance of the variable lens  300  based on a received input signal (S 2620 ). 
     As exemplarily illustrated in  FIG. 27 , the driver assistance apparatus  400  may include the input unit  420 . The driver assistance apparatus  400  may receive an input to turn an ADAS function on or off via the input unit  420 . 
     An image  2710  may be acquired via the vehicle camera  200  when the focal distance of the variable lens  300  is increased under the control of the processor  470 , in the case where an input signal to turn an ACC, SAS or CSWS function on or off is received via the input unit  420 . 
     An image  2720  may be acquired via the vehicle camera  200  when the focal distance of the variable lens  300  is reduced under the control of the processor  470 , in the case where an input signal to turn a CTA, AEB, FCW, TSR, HBA, BSD, AES, or TJA function on or off is received via the input unit  420 . 
       FIG. 28  is a flowchart referenced to describe an operation of the driver assistance apparatus in accordance with an implementation. 
       FIG. 29  is a view referenced to describe an operation of changing the focal distance of the variable lens based on a distance to an object in accordance with an implementation. 
       FIG. 30  is a view referenced to describe an operation of changing the focal distance of the variable lens based on the position of the object in accordance with an implementation. 
       FIG. 31  is a view referenced to describe an operation of changing the focal distance of the variable lens when the intersection is detected as the object in accordance with an implementation. 
     Referring to  FIG. 28 , the processor  470  may receive an image captured via the vehicle camera  200  (S 2810 ). Here, the image may be an image captured via a mono camera or an image captured via a stereo camera. 
     The processor  470  may detect an object based on the received image (S 2820 ). The processor  470  may perform object detection, such as lane detection, vehicle detection, pedestrian detection, bright-spot detection, traffic sign recognition, or road surface detection. 
     For example, another vehicle may be a preceding vehicle, a following vehicle, a vehicle being driven in the neighboring lane, a vehicle that has been involved in an accident, or an ACC follow-up vehicle. 
     The processor  470  may change the focal distance of the variable lens  300  based on the detected object (S 2830 ). 
     The processor  470  may change the focal distance of the variable lens  300  based on the distance to the object or the position of the object. 
     The processor  470  may calculate the distance to the object detected based on the acquired image. The processor  470  may calculate the distance via the method described with reference to  FIGS. 20A to 21 . When the image is an image captured via a stereo camera, the processor  470  may calculate the distance to the object via disparity calculation. 
     As exemplarily illustrated in  FIG. 29 , the processor  470  may gradually increase the focal distance of the variable lens  300  as the distance to the object is gradually increased. 
     An image  2910  may be captured via the vehicle camera  200  in the first focal distance state of the variable lens  300 . The processor  470  may detect an object  2915  from the image. The processor  470  may calculate the distance to the object  2915 . In  FIG. 29 , the distance to the object  2915  is assumed to be 40 m. 
     An image  2920  may be captured via the vehicle camera  200  in the state in which the distance to a detected object  2925  is increased to 100 m. In this case, the processor  470  may gradually increase the focal distance of the variable lens  300 . The processor  470  may change the focal distance so that an image is captured about the object  2925 . 
     Because the distance to the object  2925  is increased, the processor  470  may increase the focal distance of the variable lens  300 . As such, although the FOV of the vehicle camera  200  is reduced, capturing an image of a remote object is possible. 
     The processor  470  may gradually reduce the focal distance of the variable lens  300  as the distance to the object is gradually reduced. 
     The processor  470  may calculate the position of the object detected based on the acquired image. For example, the processor  470  may calculate the position of the object relative to the vehicle  100  based on pixels corresponding to the position of the image in the image. 
     As exemplarily illustrated in  FIG. 30 , the processor  470  may control the variable lens  300  so that the ROI of the image is changed based on the position of the object. 
     An image  3010  may be captured via the vehicle camera  200  in the first focal distance state of the variable lens  300 . The processor  470  may detect an object  3015  from an image. The processor  470  may calculate the position of the object  3015 . 
     An image  2920  may be captured via the vehicle camera  200  in the state in which the ROI of the image is changed about an object  3025 . The processor  470  may change the ROI of the image so that the object  3025  is centered on the image by controlling a voltage applied to the variable lens  300 . 
     As described above, changing the ROI of the image may accurately provide the vehicle or the driver with required information. 
     As exemplarily illustrated in  FIG. 31 , the processor  470  may detect an intersection  3100  as an object. 
     The processor  470  may detect the intersection  3100  via the detection of a signal light  3105  that is located at the intersection. The processor  470  may detect the intersection  3100  via the detection of an intersection directional sign  3107 . The processor  470  may detect the intersection  3100  via lane detection. The processor  470  may detect the intersection  3100  via the detection of another vehicle that is being driven in the direction crossing the direction of travel of the vehicle  100 . The processor  470  may detect the intersection  3100  via road surface detection. 
     When the intersection  3100  is detected as an object, the processor  470  may reduce the focal distance of the variable lens  300 . 
     An image  3110  may be captured via the vehicle camera  200  before the detection of the intersection  3100 . An image  3120  may be captured via the vehicle camera  200  after the detection of the intersection  3100 . For example, the image  3120  may be captured via the vehicle camera  200  in the state in which the focal distance of the variable lens  300  is reduced. 
     When the vehicle  100  is being driven through the intersection, it is necessary to detect objects crossing the direction of travel of the vehicle  100  as well as objects moving parallel to the direction of travel. In this case, an image captured via a camera having a wide FOV is advantageous for object detection. Upon detection of the intersection, reducing the focal distance of the variable lens  300  may increase the FOV of the camera. 
       FIGS. 32A and 32B  are block diagrams referenced to describe the internal configuration of the processor when the vehicle camera includes a stereo camera in accordance with an implementation. 
     First, referring to  FIG. 32A  that is a block diagram illustrating one example the internal configuration of the processor  470 , the processor  470  included in the driver assistance apparatus  400  may include an image preprocessor  3210 , a disparity calculator  3220 , a segmentation unit  3232 , an object detector  3234 , an object verification unit  3236 , an object tracking unit  3240 , and an application unit  3250 . 
     The image preprocessor  3210  may receive an image from the camera  200  and perform preprocessing on the image. 
     For example, the image preprocessor  3210  may perform, for example, noise reduction, rectification, calibration, color enhancement, color space conversion (CSC), interpolation, or camera gain control on the image. Thereby, a more vivid image than the stereo image captured via the camera  200  may be acquired. 
     The disparity calculator  3220  may receive the image signal-processed by the image preprocessor  3210 , perform stereo matching for the received images, and acquire a disparity map based on the stereo matching. For example, disparity information related to a stereo image of the view in front of the vehicle may be acquired. 
     The stereo matching may be performed on a per pixel basis or on a per prescribed block basis of stereo images. The disparity map may refer to a map showing binocular parallax information between stereo images, e.g., left and right images as numerical values. 
     The segmentation unit  3232  may perform segmentation and clustering on at least one of the images based on the disparity information from the disparity calculator  3220 . 
     As a specific example, the segmentation unit  3232  may segment at least one of the stereo images into a background and a foreground based on the disparity information. 
     For example, a region having a predetermined value or less of the disparity information in the disparity map may be calculated as a background, and the corresponding region may be excluded. As a result, a foreground may be relatively separated from the image. 
     In another example, a region having a predetermined value or more of the disparity information in the disparity map may be calculated as a foreground, and the corresponding region may be extracted. As a result, the foreground may be separated from the image. 
     As described above, as the foreground and the background are separated based on the disparity information extracted based on the stereo images, for example, signal processing speed and signal processing amount may be reduced during object detection. 
     Subsequently, the object detector  3234  may detect an object based on an image segment from the segmentation unit  3232 . 
     For example, the object detector  3234  may detect an object for at least one of the images based on the disparity information. 
     For example, the object detector  3234  may detect an object for at least one of the images. For example, the object detector  3234  may detect an object from a foreground separated from the image by the image segment. 
     Subsequently, the object verification unit  3236  may classify and verify the separated object. 
     To this end, the object verification unit  3236  may use, for example, an identification method using a neural network, a Support Vector Machine (SVM) method, an AdaBoost identification method using a Harr-like feature, or a Histograms of Oriented Gradients (HOG) method. 
     The object verification unit  3236  may compare the detected object with objects stored in the memory  440  to verify the detected object. 
     For example, the object verification unit  3236  may verify an adjacent vehicle, a traffic lane marker, road surface, a traffic sign, a dangerous zone, and a tunnel, located around the vehicle  100 . 
     The object tracking unit  3240  may track the verified object. For example, the object tracking unit  3240  may sequentially verify an object in the acquired stereo images, calculate motion or a motion vector of the verified object, and track movement of the object based on the calculated motion or the calculated motion vector. Consequently, the object tracking unit  3240  may track, for example, an adjacent vehicle, a traffic lane marker, road surface, a traffic sign, a dangerous area, and a tunnel located around the vehicle  100 . 
     Subsequently, the application unit  3250  may calculate, for example, the accident risk of the vehicle  100  based on various objects (e.g. other vehicles, traffic lane markers, road surface, and traffic signs) located around the vehicle  100 . In addition, the application unit  3250  may calculate the possibility of head-on collision with a preceding vehicle and whether or not loss of traction occurs. 
     In addition, the application unit  3250  may output, for example, a message to notify a user of driver assistance information, such as the calculated risk, collision possibility, or traction loss. Alternatively, the application unit  3250  may generate a control signal, as vehicle control information, for the attitude control or traveling control of the vehicle  100 . 
     In some implementations, some of the image preprocessor  3210 , the disparity calculator  3220 , the segmentation unit  3232 , the object detector  3234 , the object verification unit  3236 , the object tracking unit  3240 , and the application unit  3250  may be included in the processor  470 . 
       FIG. 32B  is a block diagram illustrating another example the internal configuration of the processor  470  in accordance with an implementation. 
     Referring to  FIG. 32B , the processor  470  of  FIG. 32B  has the same inner constituent units as those of the processor  470  of  FIG. 32A , but has a difference in terms of signal processing sequence. Hereinafter, only the difference will be described. 
     The object detector  3234  may receive stereo images, and detect an object from at least one of the stereo images. Unlike  FIG. 32A , the object detector  3234  may directly detect an object from the stereo image, rather than detecting an object from a segmented image based on disparity information. 
     Subsequently, the object verification unit  3236  may classify and verify the detected and separated object based on the image segment from the segmentation unit  3232  and the object detected in the object detection unit  3234 . 
     To this end, the object verification unit  3236  may use, for example, an identification method using a neural network, a Support Vector Machine (SVM) method, an AdaBoost identification method using a Harr-like feature, or a Histograms of Oriented Gradients (HOG) method. 
       FIGS. 33A and 33B  are views referenced to describe a method of operating the processor  470  of  FIG. 19  based on stereo images acquired respectively during first and second frame periods in accordance with an implementation. 
     First, referring to  FIG. 33A , the stereo camera  200  acquires stereo images during a first frame period. 
     The disparity calculator  3220  included in the processor  470  receives stereo images FR 1   a  and FR 1   b  signal-processed by the image preprocessor  3210  and performs stereo matching for the received stereo images FR 1   a  and FR 1   b  to acquire a disparity map  3320 . 
     The disparity map  3320  shows a binocular disparity between the stereo images FR 1   a  and FR 1   b  as levels. As the disparity level is higher, the distance to the vehicle may be calculated as being shorter. As the disparity level is lower, the distance to the vehicle may be calculated as being longer. 
     When the disparity map is displayed, the disparity map may be displayed with higher brightness as the disparity level is higher and displayed with lower brightness as the disparity level is lower. 
       FIG. 33A  illustrates, by way of example, that, in the disparity map  3320 , first to fourth traffic lane markers  3328   a ,  3328   b ,  3328   c , and  3328   d  have their own disparity levels and a roadwork zone  3322 , a first preceding vehicle  3324 , and a second preceding vehicle  3326  have their own disparity levels. 
     The segmentation unit  3232 , the object detector  3234 , and the object verification unit  3236  respectively perform segmentation, object detection, and object verification for at least one of the stereo images FR 1   a  and FR 1   b  based on the disparity map  3320 . 
       FIG. 33A  illustrates, by way of example, that object detection and object verification for the second stereo image FR 1   b  are performed using the disparity map  3320 . 
     For example, object detection and object verification for first to fourth traffic lane markers  3338   a ,  3338   b ,  3338   c , and  3338   d , a roadwork zone  3332 , a first preceding vehicle  3334 , and a second preceding vehicle  3336  in an image  3330  may be performed. 
     Subsequently, referring to  FIG. 33B , the stereo camera  200  acquires stereo images during a second frame period. 
     The disparity calculator  3220  included in the processor  470  receives stereo images FR 2   a  and FR 2   b  signal-processed by the image preprocessor  3210  and performs stereo matching for the received stereo images FR 2   a  and FR 2   b  to acquire a disparity map  3340 . 
       FIG. 33B  shows, by way of example, that, in the disparity map  3340 , first to fourth traffic lane markers  3348   a ,  3348   b ,  3348   c , and  3348   d  have their own disparity levels and a roadwork zone  3342 , a first preceding vehicle  3344 , and a second preceding vehicle  3346  have their own disparity levels. 
     The segmentation unit  3232 , the object detector  3234 , and the object verification unit  3236  respectively perform segmentation, object detection, and object verification for at least one of the stereo images FR 2   a  and FR 2   b  based on the disparity map  3340 . 
       FIG. 33B  shows, by way of example, that object detection and object verification for the second stereo image FR 2   b  are performed using the disparity map  3340 . 
     For example, object detection and object verification for first to fourth traffic lane markers  3358   a ,  3358   b ,  3358   c , and  3358   d , a roadwork zone  3352 , a first preceding vehicle  3354 , and a second preceding vehicle  3356  in an image  3350  may be performed. 
     The object tracking unit  3240  may track verified objects by comparing  FIGS. 33A and 33B  with each other. 
     In some implementations, the object tracking unit  3240  may track, for example, movement of an object based on the motion or motion vectors of respective objects verified from  FIGS. 33A and 33B . As such, the object tracking unit  3240  may track, for example, traffic lane markers, a roadwork zone, a first preceding vehicle and a second preceding vehicle, which are located around the vehicle  100 . 
       FIGS. 34 to 39  are views referenced to describe an operation of acquiring stereo images and calculating disparity when the left variable lens  300 L and the right variable lens  300 R included in the respective stereo cameras have different focal distances in accordance with an implementation. 
     The stereo camera  200  may include a first camera and a second camera. 
     The first camera may include the left variable lens  300 L and the first image sensor  214   a.    
     The second camera may include the right variable lens  300 R and the second image sensor  214   b.    
     In the following description, the focal distance of the left variable lens  300 L is longer than the focal distance of the right variable lens  300 R. The left variable lens  300 L is advantageous for image capture at a long distance, and the right variable lens  300 R is advantageous for image capture at a short distance. 
       FIG. 34  is a block diagram referenced to describe the internal configuration of the processor when the vehicle camera includes a stereo camera in accordance with an implementation. 
     Referring to  FIG. 34 , the processor  470  may include an image preprocessor  3410 , a binning processor  3412 , a first object detector  3413 , a cropping processor  3414 , a second object detector  3415 , a stereo image producer  3417 , a disparity calculator  3420 , a third object detector  3434 , an object verification unit  3436 , an object tracking unit  3440 , and an application unit  3450 . 
     The image preprocessor  3410  may receive an image from the stereo camera  200  and perform preprocessing on the image. 
     For example, the image preprocessor  3410  may perform, for example, noise reduction, rectification, calibration, color enhancement, color space conversion (CSC), interpolation, or camera gain control on the image. Thereby, a more vivid image than the stereo image captured via the camera  200  may be acquired. 
     The binning processor  3412  may perform binning on the first image received from the first camera of the stereo camera  200 . Here, the image input to the binning processor  3412  may be the image preprocessed in the image preprocessor  3410 . The binning processor  3412  may combine information regarding at least two pixels of the first image into information regarding one pixel. Thereby, the binning may reduce the resolution of the first image. 
     The binning processor  3412  may perform binning on some of a plurality of frames of the first image that are not successive. 
     The first object detector  3413  may detect an object based on the first image received from the first camera among the stereo camera  200 . Here, the image input to the first object detector  3413  may be the image preprocessed in the image preprocessor  3410 . 
     The first object detector  3413  may calculate the distance to the detected object and the speed of the vehicle relative to the object. The first object detector  3413  may track the detected object, and may calculate the distance to the object based on the size of the object, which is changed as time passes. The first object detector  3413  may calculate the speed of the vehicle relative to the object based on the distance to the object. 
     The cropping processor  3414  may perform cropping on the second image received from the second camera of the stereo camera  200 . Here, the image input to the cropping processor  3414  may be the image preprocessed in the image preprocessor  3410 . The cropping processor  3414  may cut off an undesired region of the second image. 
     The cropping processor  3414  may perform cropping some of a plurality of frames of the second image that are not successive. 
     The second object detector  3415  may detect an object based on the second image received from the second camera among the stereo camera  200 . Here, the image input to the second object detector  3415  may be the image preprocessed in the image preprocessor  3410 . 
     The second object detector  3415  may calculate the distance to the detected object and the speed of the vehicle relative to the object. The second object detector  3415  may track the detected object, and calculate the distance to the object based on the size of the object that is changed as time passes. The second object detector  3415  may calculate the speed of the vehicle relative to the object based on the distance to the object. 
     The stereo image producer  3417  may produce a stereo image based on the binned first image and the cropped second image. The stereo image producer  3417  may produce the stereo image by performing rectification on the binned first image or the cropped second image. For example, the processor  470  may produce the stereo image after matching the sizes of the binned first image and the cropped second image with each other by adjusting the size of any one of the first and second images. For example, the processor  470  may produce the stereo image after matching the sizes of the binned first image and the cropped second image with each other by adjusting the sizes of both the images. 
     The disparity calculator  3420  may perform stereo matching for the received images, and acquire a disparity map based on the stereo matching. For example, disparity information related to a stereo image of the view in front of the vehicle may be acquired. 
     The stereo matching may be performed on a per pixel basis or on a per prescribed block basis of stereo images. The disparity map may refer to a map showing binocular parallax information between stereo images, e.g., left and right images as numerical values. 
     The third object detector  3434  may detect an object. 
     For example, the third object detector  3434  may detect an object from at least one image based on disparity information. 
     For example, the object detector  3434  may detect an object from at least one of the images. 
     The object verification unit  3436  may classify and verify the detected objects. 
     The object verification unit  3436  may classify and verify the objects detected by the first object detector  3413 , the second object detector  3415 , and the third object detector  3434 . 
     To this end, the object verification unit  3436  may use, for example, an identification method using a neural network, a Support Vector Machine (SVM) method, an AdaBoost identification method using a Harr-like feature, or a Histograms of Oriented Gradients (HOG) method. 
     The object verification unit  3436  may compare the detected objects with objects stored in the memory  440  to verify the detected objects. 
     For example, the object verification unit  3436  may verify an adjacent vehicle, a traffic lane marker, road surface, a traffic sign, a dangerous zone, and a tunnel, located around the vehicle. 
     The object tracking unit  3440  may track the verified objects. For example, the object tracking unit  3440  may sequentially verify an object in the acquired stereo images, calculate motion or a motion vector of the verified object, and track movement of the object based on the calculated motion or the calculated motion vector. Consequently, the object tracking unit  3440  may track, for example, an adjacent vehicle, a traffic lane marker, road surface, a traffic sign, a dangerous area, and a tunnel located around the vehicle  100 . 
     Subsequently, the application unit  3450  may calculate, for example, the accident risk of the vehicle  100  based on various objects (e.g. other vehicles, traffic lane markers, road surface, and traffic signs) located around the vehicle  100 . In addition, the application unit  3450  may calculate the possibility of head-on collision with a preceding vehicle and whether or not loss of traction occurs. 
     In addition, the application unit  3450  may output, for example, a message to notify a user of driver assistance information, such as the calculated risk, collision possibility, or traction loss. Alternatively, the application unit  3450  may generate a control signal, as vehicle control information, for the attitude control or traveling control of the vehicle  100 . 
     In some implementations, some of the image preprocessor  3410 , the binning the disparity calculator  3420 , the object detectors  3413 ,  3415  and  3434 , the object verification unit  3436 , the object tracking unit  3440 , and the application unit  3450  may be included in the processor  470 . 
       FIG. 35  is a view referenced to describe binning and cropping in accordance with an implementation. 
     Referring to  FIG. 35 , the processor  470  may receive a first image from the first camera of the stereo camera  200 . 
     The first image may be an image acquired via the left variable lens  300 L and the first image sensor  214   a.    
     The first image may include a plurality of frames  3511 ,  3512 ,  3513 ,  3514 ,  3515 ,  3516 , . . . . 
     The processor  470  may perform binning on the first image. For example, the processor  470  may perform binning on, for example, some frames  3511 ,  3513 ,  3515 , . . . , which are not successive, among the frames  3511 ,  3512 ,  3513 ,  3514 ,  3515 ,  3516 , . . . . 
     The processor  470  may perform binning on the first image based on the second image. 
     The processor  470  may perform binning on the first image so as to be synchronized with the second image. For example, the processor  470  may perform binning on the frames  3511 ,  3513 ,  3515 , . . . of the first image, which correspond to cropped frames  3521 ,  3523 ,  3525 , . . . of the second image. 
     The processor  470  may perform binning on the first image so as to match the resolution of the second image. For example, the processor  470  may perform binning on the first image so as to have the same resolution as the resolution of the second image. 
     The processor  470  may detect an object based on the first image. For example, the processor  470  may detect an object based on frames  3512 ,  3514 ,  3516 , . . . , which are not subjected to binning, among the frames  3511 ,  3512 ,  3513 ,  3514 ,  3515 ,  3516 , . . . . 
     An image of the frames that are not subjected to binning has a higher resolution, and thus has a greater number of pieces of information. Information regarding the object may be more accurately detected by detecting the object based on the image of the frames that are not subjected to binning. 
     The processor  470  may receive a second image from the second camera of the stereo camera  200 . 
     The second image may be an image acquired via the right variable lens  300 R and the second image sensor  214   b.    
     The second image may include a plurality of frames  3521 ,  3522 ,  3523 ,  3524 ,  3525 ,  3526 , . . . . 
     The processor  470  may perform cropping on the second image. For example, the processor  470  may perform cropping on, for example, some frames  3521 ,  3523 ,  3525 , . . . , which are not successive, among the frames  3521 ,  3522 ,  3523 ,  3524 ,  3525 ,  3526 , . . . . 
     The processor  470  may perform the cropping on the second image based on the first image. 
     The processor  470  may perform cropping on the second image so as to be synchronized with the first image. For example, the processor  470  may perform cropping on the frames  3521 ,  3523 ,  3525 , . . . of the second image, which correspond to the binned frames  3511 ,  3513 ,  3515 , . . . of the first image. 
     The processor  470  may perform cropping on the second image so as to correspond to content of the first image. For example, the processor  470  may perform cropping on the second image so as to have the same content as the content of the first image. 
     The processor  470  may detect an object based on the second image. For example, the processor  470  may detect an object based on frames  3522 ,  3524 ,  3526 , . . . , which are not subjected to cropping, among the frames  3521 ,  3522 ,  3523 ,  3524 ,  3525 ,  3526 , . . . . 
     An image of the frames that are not subjected to cropping has a wider field of vision, and thus has a greater number of pieces of information. Information regarding the object may be more accurately detected by detecting the object based on the image of the frames that are not subjected to cropping. 
       FIG. 36  is a view referenced to describe an operation of producing a stereo image in accordance with an implementation. 
     Referring to  FIG. 36 , the processor  470  may produce a stereo image by processing each of a first image and a second image. The processor  470  may acquire stereo images by performing binning on the first image  3511  and cropping on the second image  3521 . The processor  470  may produce stereo images by performing rectification on the binned first image or the cropped second image. For example, the processor  470  may produce the stereo image after mating the sizes of the binned first image and the cropped second image with each other by adjusting the size of any one of the first and second images. For example, the processor  470  may produce the stereo image after mating the sizes of the binned first image and the cropped second image with each other by adjusting the sizes of both the images. 
     The processor  470  may perform disparity calculation based on the stereo images  3511  and  3512 . 
       FIG. 37  is a view referenced to describe a first image in accordance with an implementation. 
     Referring to  FIG. 37 , the processor  470  may receive a first image from the first camera. The first image may be an image of the view at a long distance in front of the vehicle, which is acquired via the left variable lens  300 L and the first image sensor  214   a.    
     The processor  470  may detect an object located a long distance away from the first image. The processor  470  may detect the object from the first image even if the object is located a long distance away, but may fail to detect an object over a wide field of vision in the left-right direction. In  FIG. 37 , an area  3610  is detectable based on the properties of the first camera. 
     The processor  470  may detect an object  3710  from the first image. The detection of the object  3710  is possible because the object  3710  is included in the first image based on the FOV of the left variable lens  300 L, which is included in the first camera. An object  3720  may not be detected because it is not included in the first image based on the FOV of the left variable lens  300 L, which is included in the first camera. 
       FIG. 38  is a view referenced to describe a second image in accordance with an implementation. 
     Referring to  FIG. 38 , the processor  470  may receive a second image from the second camera. The second image may be an image of the view at a short distance in front of the vehicle, which is acquired via the wide angle camera. 
     The processor  470  may detect an object, which is located at the left side or the right side in front of the vehicle, among objects located a short distance away from the second image. The processor  470  may detect, from the second image, objects over a wide field of vision in the left-right direction, but may fail to detect an object a long distance away. In  FIG. 38 , an area  3620  is detectable based on the property of the second camera. 
     The processor  470  may detect an object  3810  from the second image. The detection of the object  3810  is possible because the object  3810  is included in the second image based on the FOV of the right variable lens  300 R, which is included in the second camera. An object  3820  may not be detected because it is not included in the second image based on the FOV of the right variable lens  300 R included in the second camera. 
       FIG. 39  is a view referenced to describe a stereo image produced based on the first image and the second image in accordance with an implementation. 
     Referring to  FIG. 39 , the processor  470  may produce stereo images by performing binning on the first image  3511  and cropping on the second image  3521 , and thereafter performing rectification on the images. The processor  470  may perform disparity calculation based on the produced stereo images. 
     The processor  470  may perform disparity calculation on an object  3910 , which is detected in the area in which the first image and the second image overlap each other. An object  3920  may be detected in the first image, but not detected in the second image. An object  3925  may be detected in the second image, but not detected in the first image. The processor  470  may not perform disparity calculation on the objects  3920  and  3925 . 
     An object  3930  is not detected in either the first image or the second image. 
       FIG. 40  is a view referenced to describe the variable lens included in the driver assistance apparatus in accordance with an implementation. 
     Referring to  FIG. 40 , the driver assistance apparatus  400  may include the camera  200  and the processor  470 . 
     The camera  200  may include the image sensor  214  and the variable lens  300 . 
     The variable lens  300  may change the light that is introduced into the image sensor  214  based on variation of the interface between polar fluid and non-polar fluid, which depends on the voltage applied thereto. 
     The variable lens  300  may be referred to as a wetting lens. 
     The variable lens  300  may include transparent plates  4011   a  and  4011   b , a first material  4012 , a second material  4013 , a catalyst member  4014 , an insulator member  4015 , and a hydrophobic member  4016 . 
     The variable lens  300  may have an approximately cylindrical shape. 
     The transparent plates  4011   a  and  4011   b  may be parallel to each other and may form the upper portion and the lower portion of the cylindrical variable lens  300 . The transparent plates  4011   a  and  4011   b  may define a space therebetween. The transparent plates  4011   a  and  4011   b  may be formed of a hydrophilic material or may be coated with a hydrophilic material. 
     A drive unit may have a ring shape, and may form the outer peripheral surface of the variable lens  300 . The drive unit may include the catalyst member  4014 , the insulator member  4015 , and the hydrophobic member  4016 . 
     The catalyst member  4014  may be formed of platinum (Pt) or palladium (Pd). The catalyst member  4014  may function as a ground electrode. 
     The insulator member  4015  is formed between the catalyst member  4014  and the hydrophobic member  4016  and functions to insulate the catalyst member  4014 , which functions as the ground function, from the hydrophobic member  4016 , which receives power. 
     The hydrophobic member  4016  may be formed by coating the surface of the electrode with a hydrophobic material. The surface of the hydrophobic member  4016  may be changed to a hydrophilic surface by an electric field created between the hydrophobic member  4016  and the catalyst member  4014  when electricity is supplied. 
     The first material  4012  and the second material  4013  may be provided in the inner space of the variable lens  300 . For example, the first material  4012  may be a polar material, such as water or liquid crystals. The second material  4013  may be a non-polar fluid. 
     The focal distance of the variable lens  300  may be changed by the potential difference of electricity supplied to both hydrophobic members  4016 . 
     Implementations described above may be implemented as code that may be written on a computer readable medium in which a program is recorded and thus read by a computer. The computer readable medium includes all kinds of recording devices in which data is stored in a computer readable manner. Examples of the computer readable recording medium may include a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disc, and an optical data storage device. In addition, the computer readable medium is implemented in a carrier wave (e.g., data transmission over the Internet). In addition, the computer may include the processor  470  or the controller  170 . 
     The above detailed description is not limited to the implementations set forth herein. The scope of the present disclosure is determined by the reasonable interpretation of the accompanying claims and all changes in the equivalent range are included.