Patent Publication Number: US-2022234583-A1

Title: Driver assistance system and driver assistance method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2021-0009190, filed on Jan. 22, 2021 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     1. Technical Field 
     The disclosure relates to a driver assistance system and a driver assistance method, and more specifically, to a driver assistance system and a driver assistance method that may rapidly determine cutting out of a preceding vehicle based on lane information obtained from a camera. 
     2. Background Art 
     A vehicle refers to a machine that transports people or cargo by driving on the road or rail. Most vehicles use at least one wheel mounted on a vehicle to move. Such vehicles include three-wheeled or four-wheeled vehicles, two-wheeled vehicles such as motorcycles, heavy construction equipment, bicycles, and railed vehicles such as trains, and the like. 
     Much research on vehicles equipped with advanced driver assistance systems (ADAS) that actively provide information about a vehicle state, a driver state and traffic environment have been recently carried out to reduce drivers&#39; burden and improve convenience. 
     In an adaptive cruise control (ACC) as an example of ADAS mounted on a vehicle, when a driver sets a vehicle speed, the vehicle speed may be maintained considering external conditions without driver pressing a brake pedal or an accelerator pedal. 
     Further, a smart cruise control system (SCC) capable of decelerating or accelerating while maintaining a distance to a preceding vehicle using a radar sensor and camera mounted on a vehicle has been recently developed. 
     Meanwhile, such SCC determines a target vehicle in front of a vehicle using a front radar and a front camera of the vehicle, and controls an acceleration control device, an engine control device, and a brake control device of the controlled vehicle using information about a relative speed and distance between the controlled vehicle and the target vehicle, a heading direction and angle of the controlled vehicle, a preset longitudinal speed and preset acceleration limit of the controlled vehicle, and the like. 
     SUMMARY 
     An aspect of the disclosure provides a driver assistance system and a driver assistance method that may rapidly change a target vehicle by quickly detecting cutting out of a preceding vehicle based on lane information obtained from a camera. 
     Additional aspects of the disclosure will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the disclosure. 
     According to an aspect of the disclosure, there is provided a driver assistance system, including: a first sensor mounted on a vehicle and configured to acquire front image data; a second sensor selected from a group including a radar sensor and a lidar sensor, mounted on the vehicle, and configured to acquire front detection data; and a controller configured to select a preceding vehicle as a target vehicle based on the front image data and the front detection data and control a speed of the vehicle to follow the target vehicle, wherein the controller is configured to: recognize a left land and a right lane of a driving lane based on the front image data, calculate a lateral speed of the preceding vehicle based on the front detection data, when a difference between a length of the left lane and a length of the right lane is greater than or equal to a preset value and the lateral speed of the preceding vehicle is greater than or equal to a preset speed, recognize the preceding vehicle as a cut-out vehicle, and recognize a preceding vehicle of the cut-out vehicle as the target vehicle. 
     The controller is configured to control the speed of the vehicle to follow the preceding vehicle of the cut-out vehicle when the cut-out vehicle is recognized, and control the speed of the vehicle to prevent the vehicle from passing the cut-out vehicle before a lane change of the cut-out vehicle is complete. 
     The controller is configured to determine a required acceleration of the vehicle based on a relative location of the cut-out vehicle and a relative speed of the preceding vehicle of the cut-out vehicle, before the lane change of the cut-out vehicle is complete. 
     The controller is configured to determine that the cut-out vehicle changes lanes in a direction of a shorter lane of the left lane and the right lane. 
     The controller is configured to recognize the cut-out vehicle as the target vehicle, when the cut-out vehicle has a speed in an opposite direction to a shorter lane of the left lane and the right lane. 
     The controller is configured to determine that a cut-in vehicle that cuts in to the driving lane from an adjacent lane exists, when a difference between a distance between the vehicle and the preceding vehicle and a length of a shorter lane of the left lane and the right lane is greater than or equal to a threshold value. 
     The controller is configured to recognize the cut-in vehicle as the target vehicle, when the cut-in vehicle exists. 
     According to an aspect of the disclosure, there is provided a driver assistance method, including: acquiring front image data of a vehicle; acquiring front detection data of the vehicle; selecting a preceding vehicle as a target vehicle based on the front image data and the front detection data; and controlling a speed of the vehicle to follow the target vehicle, wherein the selecting of the target vehicle includes: recognizing a left land and a right lane of a driving lane based on the front image data; calculating a lateral speed of the preceding vehicle based on the front detection data; when a difference between a length of the left lane and a length of the right lane is greater than or equal to a preset value and the lateral speed of the preceding vehicle is greater than or equal to a preset speed, recognizing the preceding vehicle as a cut-out vehicle, and recognizing a preceding vehicle of the cut-out vehicle as the target vehicle. 
     The controlling of the speed of the vehicle to follow the target vehicle further includes controlling the speed of the vehicle to follow the preceding vehicle of the cut-out vehicle when the cut-out vehicle is recognized, and controlling the speed of the vehicle to prevent the vehicle from passing the cut-out vehicle before a lane change of the cut-out vehicle is complete. 
     The controlling of the speed of the vehicle to prevent the vehicle from passing the cut-out vehicle before the lane change of the cut-out vehicle is complete includes determining a required acceleration of the vehicle based on a relative location of the cut-out vehicle and a relative speed of the preceding vehicle of the cut-out vehicle. 
     The driver assistance method further includes determining that the cut-out vehicle changes lanes in a direction of a shorter lane of the left lane and the right lane. 
     The selecting of the target vehicle includes recognizing the cut-out vehicle as the target vehicle, when the cut-out vehicle has a speed in an opposite direction to a shorter lane of the left lane and the right lane. 
     The driver assistance method further includes determining that a cut-in vehicle that cuts in to the driving lane from an adjacent lane exists, when a difference between a distance between the vehicle and the preceding vehicle and a length of a shorter lane of the left lane and the right lane is greater than or equal to a threshold value. 
     The selecting of the target vehicle further includes recognizing the cut-in vehicle as the target vehicle, when the cut-in vehicle exists. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  illustrates a configuration of a vehicle according to an embodiment; 
         FIG. 2  illustrates a configuration of a driver assistance system according to an embodiment; 
         FIG. 3  illustrates a camera and a radar included in a driver assistance system according to an embodiment; 
         FIG. 4  is a flowchart illustrating a driver assistance method according to an embodiment; 
         FIG. 5  is a diagram illustrating an example where a preceding vehicle changes lanes; 
         FIG. 6  is a diagram illustrating an example where a preceding vehicle attempts to change lanes and then returns to an original lane; and 
         FIG. 7  is a diagram illustrating an example where a side vehicle driving in the next lane changes lanes. 
     
    
    
     DETAILED DESCRIPTION 
     Like reference numerals throughout the specification denote like elements. Also, this specification does not describe all the elements according to embodiments of the disclosure, and descriptions well-known in the art to which the disclosure pertains or overlapped portions are omitted. The terms such as “˜part”, “˜member”, “˜module”, “˜block”, and the like may be implemented with at least one hardware or software. According to embodiments, a plurality of “˜part”, “˜member”, “˜module”, “˜block” may be embodied as a single element, or a single of “˜part”, “˜member”, “˜module”, “˜block” may include a plurality of elements. 
     It will be understood that when an element is referred to as being “connected” to another element, it can be directly or indirectly connected to the other element, wherein the indirect connection includes connection via a wireless communication network. 
     It will be understood that the terms “include” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. 
     It is to be understood that the singular forms are intended to include the plural forms as well, unless the context clearly dictates otherwise. 
     Reference numerals used for method steps are just used for convenience of explanation, but not to limit an order of the steps. Thus, unless the context clearly dictates otherwise, the written order may be practiced otherwise. 
     In this disclosure, a ‘driving lane’ may refer to a lane in which a host vehicle is travelling. 
     In this disclosure, a ‘preceding vehicle’ may refer to a vehicle which is the closest to a host vehicle among vehicles in front that are travelling in a driving lane. 
     Hereinafter, an operation principle and embodiments will be described in detail with reference to the accompanying drawings. 
       FIG. 1  illustrates a configuration of a vehicle according to an embodiment. 
     As shown in  FIG. 1 , a vehicle  1  includes an engine  10 , a transmission  20 , a braking device  30 , and a steering device  40 . The engine  10  includes a cylinder and a piston, and may generate power for driving the vehicle  1 . The transmission  20  includes a plurality of gears and may transmit the power generated by the engine  10  to vehicle wheels. The braking device  30  may decelerate or stop the vehicle  1  through friction with the vehicle wheels. The steering device  40  may change a driving direction of the vehicle  1 . 
     The vehicle  1  may include a plurality of electronic components. For example, the vehicle  1  may include an engine management system (EMS)  11 , a transmission control unit (TCU)  21 , an electronic brake control module (EBCM)  31 , an electronic power steering (EPS)  41 , a body control module (BCM)  51 , and a driver assistance system (DAS)  100 . 
     The EMS  11  may control the engine  10  in response to a driver&#39;s acceleration intention through an accelerator pedal or a request from the DAS  100 . For instance, the EMS  11  may control a torque of the engine  10 . 
     The EMS  11  may perform a fuel injection control, a fuel efficiency feedback control, a lean burn control, an ignition timing control, an idle speed control, and the like. The EMS  11  may be a single device or a plurality of devices connected through communication. 
     The TCU  21  may control the transmission  20  in response to a driver&#39;s shift command through a shift lever and/or a driving speed of the vehicle  1 . For example, the TCU  21  may adjust a shift ratio from the engine  10  to the vehicle wheels. 
     The EBCM  31  may control the braking device  30  in response to a driver&#39;s braking intention through a brake pedal and/or wheel slip. For example, the EBCM  31  may temporarily release the wheel braking in response to the wheel slip detected when braking the vehicle  1  (anti-lock braking system, ABS). The EBCM  31  may selectively release the wheel braking in response to oversteering and/or understeering detected when steering the vehicle  1  (electronic stability control, ESC). Also, the EBCM  31  may temporarily brake the wheels in response to the wheel slip detected when driving the vehicle  1  (traction control system, TCS). 
     The EPS  41  may assist operations of the steering device  40  so that a driver may easily manipulate a steering wheel according to a driver&#39;s steering intention. For instance, the EPS  41  may assist the operations of the steering device  40  to decrease a steering force when driving at a low speed or when parking, and increase a steering force when driving at a high speed. 
     The BCM  51  may control operations of electronic components that provide convenience to the driver or secure the driver safety. For example, the BCM  51  may control a head lamp, a wiper, a cluster, a multifunction switch, a turn signal, and the like. 
     The DAS  100  may assist the driver&#39;s operation (driving, braking, and steering). For instance, the DAS  100  may detect an environment (e.g., other vehicles, pedestrians, cyclists, lanes, road signs, traffic lights, etc.) in which the vehicle  1  is travelling, and control driving and/or braking and/or steering of the vehicle  1  in response to the detected environment. 
     As another example, the DAS  100  may receive a high definition map at a current location of the vehicle  1  from a server through a communicator  160 , and control driving and/or braking and/or steering of the vehicle  1  in response to the received high definition map. 
     The DAS  100  may provide the driver with a variety of functions. For example, the DAS  100  may provide functions such as a lane departure warning (LDW), a lane keeping assist (LKA), a high beam assist (HBA), an autonomous emergency braking (AEB), a traffic sign recognition (TSR), a smart cruise control (SCC), a blind spot detection (BSD), and the like. 
     The DAS  100  may include a camera module  101  that acquires image data around the vehicle  1  and a radar module  102  that acquires data about objects around the vehicle  1 . The camera module  101  includes a camera  101   a  and an electronic control unit (ECU)  101   b , and may photograph a front of the vehicle  1  and recognize other vehicles, pedestrians, cyclists, lanes, road signs, structures, etc. The radar module  102  includes a radar  102   a  and an ECU  102   b , and may acquire a relative location, a relative speed, and etc., of the objects (e.g., other vehicles, pedestrians, cyclists, structures, etc.) around the vehicle  1 . 
     That is, the DAS  100  may process the image data acquired by the camera module  101  and detection data acquired by the radar module  102 , and detect the environment in which the vehicle  1  is travelling, a front object located in front of the vehicle  1  and a lateral object located on the sides of the vehicle  1 , in response to processing the image data and the detection data. 
     Position information of the vehicle  1  is required to be determined so that the DAS  100  performs a fully autonomous driving. Accordingly, the DAS  100  may include a global positioning system (GPS) module  105 . 
     The GPS module  105  may receive a satellite signal including navigation data from at least one GPS satellite. The DAS  100  may acquire a current location, a heading direction, and the like, of the vehicle  1  based on the satellite signal. 
     As an autonomous driving system is advanced, the DAS  100  for performing autonomous driving is required to calculate a position of the vehicle  1  more precisely. 
     Accordingly, the DAS  100  may include a light detection and ranging (lidar) module  103  that detects an object around the vehicle  1  by scanning around the vehicle  1 . The lidar module  103  includes a lidar  103   a  and an ECU  103   b , and may acquire a relative location, a relative speed, and etc., of a moving object (e.g., other vehicles, pedestrians, cyclists, structures, etc.) around the vehicle  1 . Also, the lidar module  103  may acquire a shape and location of a fixed object (e.g., buildings, signs, traffic lights, speed bumps, etc.) around the vehicle  1 . 
     Specifically, the lidar module  103  may acquire point cloud data for an outside field of view of the vehicle  1  to acquire the shape and location of the fixed object around the vehicle  1 . 
     Also, the DAS  100  may include a communicator  160  that receives the high definition map at the current location of the vehicle  1  from a cloud server. In this instance, the high definition map may refer to a map including information about traffic lights, road signs, curbs, markings, various types of structures, as well as lane information such as a center line, a boundary line, etc., in a three-dimensional (3D) digital form. 
     The communicator  160  may be implemented using a communication chip, an antenna, and related components to access a wireless communication network. That is, the communicator  160  may be implemented as various types of communication modules capable of long distance communication with an external server. That is, the communicator  160  may include a wireless communication module that may wirelessly transmit and receive data with the external server. 
     The DAS  100  may process GPS data obtained from the GPS module  105  and/or the point cloud data obtained from the lidar module  103  and/or the high definition map obtained from the communicator  160 . Also, the DAS  100  may acquire position information of the vehicle  1  according to the processing result and control the movement of the vehicle  1 . 
     The above-described electronic components may communicate with each other via a vehicle communication network (NT). For example, the electronic components may transmit/receive data through Ethernet, media oriented systems transport (MOST), FlexRay, controller area network (CAN), local interconnect network (LIN), and the like. For example, the DAS  100  may transmit a driving control signal, a braking signal, and a steering signal to the EMS  11 , the EBCM  31 , and the EPS  41 , respectively, through the vehicle communication network (NT). 
       FIG. 2  illustrates a configuration of a driver assistance system according to an embodiment.  FIG. 3  illustrates a camera and a radar included in a driver assistance system according to an embodiment. 
     As shown in  FIG. 2 , the vehicle  1  may include an acceleration system  12 , a braking system  32 , a steering system  42  and the DAS  100 . 
     The acceleration system  12  may include the EMS  11  (refer to  FIG. 1 ) and the engine  10  (refer to  FIG. 1 ). The braking system  32  may include the EBCM  31  (refer to  FIG. 1 ) and the braking device  30  (refer to  FIG. 1 ), and the steering system  42  may include the EPS  41  (refer to  FIG. 1 ) and the steering device  40  (refer to  FIG. 1 ). 
     The DAS  100  may include a front camera  110  and a front radar  120 . 
     As shown in  FIG. 3 , the front camera  110  may have a field of view  110   a  facing the front of the vehicle  1 . For example, the front camera  110  may be installed on a front windshield of the vehicle  1 . 
     The front camera  110  may photograph a front of the vehicle  1  and acquire image data of the front of the vehicle  1 . 
     The front camera  110  may include a plurality of lens and image sensors. The image sensors may include a plurality of photodiodes converting light into an electrical signal, and the plurality of photodiodes may be arranged in a two-dimensional (2D) matrix. 
     The front camera  110  may be electrically connected to the controller  140 . For instance, the front camera  110  may be connected to the controller  140  via a vehicle communication network (NT), a hard wire, or a printed circuit board (PCB). 
     Accordingly, the front camera  110  may transmit the image data of the front of the vehicle  1  to the controller  140 . 
     As shown in  FIG. 3 , the front radar  120  may have a field of sensing  120   a  facing the front of the vehicle  1 . For example, the front radar  120  may be installed in a grille or a bumper of the vehicle  1 . 
     The front radar  120  may include a transmission antenna (or a transmission antenna array) that transmits a transmission wave toward the front of the vehicle  1 , and a receiving antenna (or a receiving antenna array) that receives a reflected wave reflected from an object. The front radar  120  may acquire front radar data from the transmission wave transmitted by the transmission antenna and the reflected wave received by the receiving antenna. The front radar data may include distance information and speed information about other vehicles, pedestrians or cyclists located in front of the vehicle  1 . The speed information may include both longitudinal speed information and lateral speed information. The front radar  120  may calculate a relative distance to an object based on a phase difference (or a time difference) between the transmission wave and the reflected wave, and calculate a relative speed of the object based on a frequency difference between the transmission wave and the reflected wave. 
     For instance, the front radar  120  may be connected to the controller  140  via a vehicle communication network (NT), a hard wire, or a PCB. Accordingly, the front radar  120  may transmit the front radar data to the controller  140 . 
     Also, the DAS  100  may further include a plurality of corner radars  130 . The plurality of corner radars  130  include a first corner radar  131  installed on a front right side of the vehicle  1 , a second corner radar  132  installed on a front left side of the vehicle  1 , a third corner radar  133  installed on a rear right side of the vehicle  1 , and a fourth corner radar  134  installed on a rear left side of the vehicle  1 . 
     As shown in  FIG. 3 , the first corner radar  131  may have a field of sensing  131   a  facing the front right side of the vehicle  1 , and the front radar  120  may be installed on a right side of a front bumper of the vehicle  1 . The second corner radar  132  may have a field of sensing  132   a  facing the front left side of the vehicle  1 , and may be installed on a left side of the front bumper of the vehicle  1 . The third corner radar  133  may have a field of sensing  133   a  facing the rear right side of the vehicle  1 , and may be installed on a right side of a rear bumper of the vehicle  1 . The fourth corner radar  134  may have a field of sensing  134   a  facing the rear left side of the vehicle  1 , and may be installed on a left side of the rear bumper of the vehicle  1 . 
     Each of the first to fourth corner radars  131 ,  132 ,  133  and  134  may include a transmission antenna and a receiving antenna. The first to fourth corner radars  131 ,  132 ,  133  and  134  may acquire first corner radar data, second corner radar data, third corner radar data, and fourth corner radar data, respectively. The first corner radar data may include distance information and speed information about other vehicles, pedestrians, or cyclists (hereinafter, referred to as “object”) located on the front right side of the vehicle  1 . The second corner radar data may include distance information and speed information about an object located on the front left side of the vehicle  1 . The third and fourth corner radar data may include distance information and speed information about objects located on the rear right side or and the rear left side of the vehicle  1 . 
     For example, each of the first to fourth corner radars  131 ,  132 ,  133  and  134  may be connected to the controller  140  via a vehicle communication network (NT), a hard wire, or a PCB. Also, the first to fourth corner radars  131 ,  132 ,  133  and  134  may transmit to the controller  140  the first to fourth corner radar data, respectively. 
     The controller  140  may include the ECU  101   b  (refer to  FIG. 1 ) of the camera module  101  (refer to  FIG. 1 ), and/or the ECU  102   b  (refer to  FIG. 1 ) of the radar module  102  (refer to  FIG. 1 ), and/or a separate integrated controller. 
     The controller  140  may include a processor  141  and a memory  142 . 
     The processor  141  may process front image data of the front camera  110  and front radar data of the front radar  120 , and generate a driving signal, a braking signal and a steering signal for controlling the acceleration system  12 , the braking system  32  and the steering system  42 , respectively. For example, the processor  141  may include an image processor for processing the front image data of the front camera  110 , and/or a digital signal processor for processing radar data of the front radar  120 , and/or a micro control unit (MCU) for generating the driving signal, the braking signal and the steering signal. 
     The processor  141  may recognize objects (e.g., a preceding vehicle) in front of the vehicle  1  based on the front image data of the front camera  110  and the front radar data of the front radar  120 . 
     Specifically, the processor  141  may acquire locations (distance and direction) and relative speeds of the objects in front of the vehicle  1  based on the front radar data of the front radar  120 , and also acquire lane information and/or location (direction) and/or type information of the objects in front of the vehicle  1  based on the front image data of the front camera  110 . Also, the processor  141  may match the objects detected by the front image data with the objects detected by the front radar data, and acquire the type information, location and relative speeds of the objects in front of the vehicle  1  based on the matching result. 
     When a preceding vehicle is recognized from the front image data and/or the front radar data, the processor  141  may select the recognized preceding vehicle as a target vehicle. 
     In this instance, the processor  141  may select the preceding vehicle as the target vehicle, when a preceding vehicle recognized from the front image data matches a preceding vehicle recognized from the front radar data. 
     Afterwards, the processor  141  may control the acceleration system  12 , the braking system  32  and the steering system  42  to maintain a distance between the vehicle  1  and the target vehicle. 
     For example, when the distance between the vehicle  1  and the target vehicle is greater than a preset distance, the processor  141  may control the acceleration system  12  to accelerate the vehicle  1  in order to maintain the distance between the vehicle  1  and the target vehicle. 
     That is, the processor  141  may control a speed of the vehicle  1  to follow the target vehicle. In this instance, the processor  141  may determine a required acceleration to follow the target vehicle and control the acceleration system  12  and/or the braking system  32  to accelerate the vehicle  1  to the required acceleration. 
     The memory  142  may store a program and/or data for the processer  141  to process image data, a program and/or data for the processer  141  to process radar data, and a program and/or data for the processer  141  to generate the driving signal, and/or the braking signal, and/or the steering signal. 
     The memory  142  may temporarily store the image data received from the front camera  110  and/or the radar data received from the front radar  120 . Also, the memory  142  may temporarily store a processing result of the image data and/or the radar data by the processor  141 . 
     The memory  142  may include a volatile memory such as a static random access memory (S-RAM) and dynamic random access memory (D-RAM), and a non-volatile memory such as a flash memory, a read only memory (ROM), an erasable programmable read only memory (EPROM), and the like. 
     The DAS  100  is not limited to that illustrated in  FIG. 2 , and may further include a lidar that detects objects by scanning around the vehicle  1 . 
     Hereinafter, radar data obtained from a radar and lidar data obtained from a lidar are collectively referred to as detection data, and a driver assistance method according to an embodiment is described in detail based on the above-described configurations of the vehicle  1  and the driver assistance system  100 . 
       FIG. 4  is a flowchart illustrating a driver assistance method according to an embodiment.  FIG. 5  is a diagram illustrating an example where a preceding vehicle changes lanes.  FIG. 6  is a diagram illustrating an example where a preceding vehicle attempts to change lanes and then returns to an original lane.  FIG. 7  is a diagram illustrating an example where a side vehicle driving in the next lane changes lanes. 
     Referring to  FIG. 4 , the front camera  110  and the front radar  120  and/or the lidar may acquire front image data and front detection data of the vehicle  1 , respectively, and transmit to the controller  140  the front image data and the front detection data, respectively. 
     The controller  140  may process the front image data and the front detection data, and select a preceding vehicle as a target vehicle in response to processing the front image data and the front detection data ( 1000 ). 
     Although not illustrated, the DAS  100  may include a smart cruise control (SCC) system, and when the SCC is activated, may control a speed of the vehicle  1  to follow the target vehicle. 
     The controller  140  may recognize a left lane and a right lane of a driving lane based on the front image data. A variety of image processing methods at common general knowledge level may be used to recognize the lanes of the driving lane. 
     The controller  140  may determine whether a difference between a length of the left lane and a length of the right lane recognized based on the front image data is greater than or equal to a preset value ( 1100 ). When the difference between the length of the left lane and the length of the right lane is greater than or equal to the preset value (Yes in operation  1100 ), the controller  140  may recognize the preceding vehicle as a cut-out vehicle or a cut-in vehicle. 
     Specifically, when the difference between the length of the left lane and the length of the right lane is greater than or equal to the preset value, the controller  140  may determine whether a difference between a distance between the vehicle  1  and the preceding vehicle and a length of a shorter lane of the left lane and the right lane is greater than or equal to a threshold value X ( 1200 ). 
     In this instance, the cut-in vehicle may refer to a vehicle that attempts to cut in to the driving lane from an adjacent lane. 
     When the distance between the vehicle  1  and the preceding vehicle and the length of the shorter lane of the left lane and the right lane is less than the threshold value X (No in operation  1200 ) and a lateral speed of the preceding vehicle is greater than or equal to a preset speed (Yes in operation  1300 ), the controller  140  may recognize the preceding vehicle as the cut-out vehicle ( 1400 ). 
     In this instance, the cut-out vehicle may refer to a vehicle that attempts to deviate from the driving lane. 
     The controller  140  may recognize the preceding vehicle selected as the target vehicle as the cut-out vehicle, recognize a preceding vehicle of the cut-out vehicle as the target vehicle, thereby may change the target vehicle ( 1500 ). 
     Referring to  FIG. 5 , when a preceding vehicle  2  selected as a target vehicle changes lanes, a length of a left lane (LL) and a length of a right lane (RL) recognized from front image data may be different from each other. 
     That is, when the preceding vehicle  2  selected as the target vehicle changes lanes, a difference between the length of the left lane (LL) and the length of the right lane (RL) recognized from the front image data may be greater than or equal to a preset value. 
     In this case, the controller  140  may predict that the preceding vehicle  2  selected as the target vehicle may deviate from a driving lane, and when a lateral speed V 1  of the preceding vehicle  2  is greater than or equal to a preset speed, the controller  140  may recognize the preceding vehicle  2  as a cut-out vehicle. 
     Afterwards, by recognizing a preceding vehicle  3  of the cut-out vehicle  2  as a target vehicle, the controller  140  may quickly predict a lane change of the cut-out vehicle  2  even before the cut-out vehicle  2  changes lanes, and rapidly change the target vehicle to the pre-preceding vehicle  3 . 
     In this instance, the controller  140  may determine that the cut-out vehicle  2  changes lanes in a direction of a shorter lane (LL) of the left lane (LL) and the right lane (RL). 
     Also, when a difference between a distance between the vehicle  1  and the preceding vehicle  2  and a length of the shorter lane (LL) of the left lane (LL) and the right lane (RL) is less than or equal to the threshold value X, the controller  140  may recognize the preceding vehicle  2  as the cut-out vehicle, and the threshold value X may be set to an overall length of a general vehicle and stored in the memory  142 . 
     When the difference between the distance between the vehicle  1  and the preceding vehicle  2  and the length of the shorter lane (LL) of the left lane (LL) and the right lane (RL) is greater than or equal to the threshold value X, which may indicate that the length of the left lane (LL) is not shortened due to the lane change of the preceding vehicle  2 . 
     When the cut-out vehicle  2  is recognized, the controller  140  may control a speed of the vehicle  1  to follow the preceding vehicle  3  of the cut-out vehicle  2 , and also control the speed of the vehicle  1  to prevent the vehicle  1  from passing the cut-out vehicle  2 , before the lane change of the cut-out vehicle  2  is complete. 
     For example, before the lane change of the cut-out vehicle  2  is complete, the controller  140  may determine a required acceleration of the vehicle  1  based on a relative location of the cut-out vehicle  2  and a relative speed of the preceding vehicle  3  of the cut-out vehicle  2 . 
     That is, by determining the required acceleration of the vehicle  1  based on the relative location of the cut-out vehicle  2  and the relative speed of the target vehicle  3 , the controller  140  may determine an optimum required acceleration that may follow the target vehicle  3  while preventing a collision with the cut-out vehicle  2 . 
     When the preceding vehicle  3  of the cut-out vehicle  2  is selected as the target vehicle and the required acceleration of the vehicle  1  is determined based on only relative location and relative speed of the target vehicle  3 , the vehicle  1  may collide with the cut-out vehicle  2 . 
     As an example, referring to  FIG. 6 , when the vehicle  1  follows the target vehicle  3  even when the preceding vehicle  2  recognized as the cut-out vehicle is returned to the driving lane again, a collision between the vehicle  1  and the preceding vehicle  2  may occur. 
     To prevent this, when the cut-out vehicle  2  has a speed V 2  in an opposite direction to the shorter lane (LL) of the left lane (LL) and the right lane (RL), the controller  140  may recognize the cut-out vehicle  2  as the target vehicle again. 
     According to an embodiment of the disclosure, the target vehicle may be changed by rapidly determining the cut-out vehicle, and thus an optimum required acceleration of the vehicle  1  may be determined and a collision with the cut-out vehicle may be efficiently prevented. 
     Referring again to  FIG. 4 , when the difference between the distance between the vehicle  1  and the preceding vehicle and the length of the shorter lane of the left lane and the right lane is greater than or equal to the threshold value X (Yes in operation  1200 ), the controller  140  may determine that a cut-in vehicle that cuts in to the driving lane from an adjacent lane exists ( 1210 ). 
     Afterwards, when the cut-in vehicle exists, the controller  140  may recognize the cut-in vehicle as the target vehicle ( 1220 ). 
     Specifically, referring to  FIG. 7 , when a difference between a distance dl between the vehicle  1  and the preceding vehicle  2  selected as the target vehicle and the length of the left lane (LL) is greater than or equal to the threshold value X, it may be confirmed that the length of the left lane (LL) shorter than that of the right lane (RL) is not caused by the target vehicle  2 . 
     In this case, it may be confirmed that the length of the left lane (LL) shorter than that of the right lane (RL) is caused by another vehicle  4  that cuts in to the driving lane from an adjacent lane. 
     That is, when the difference between the distance dl between the vehicle  1  and the preceding vehicle  2  and the length of the shorter lane (LL) of the left lane (LL) and the right lane (RL) is greater than or equal to the threshold value X, the controller  140  may determine that the cut-in vehicle  4  that cuts in to the driving lane from the adjacent lane exists, and also recognize the cut-in vehicle  4  as the target vehicle. 
     According to the disclosure, it may be rapidly determined whether a cut-in vehicle or a cut-out vehicle exists based on lane information acquired from front image data, and a target vehicle may be changed depending on the presence or absence of the cut-in vehicle or cut-out vehicle, thereby improving a performance of the driver assistance system. 
     As is apparent from the above, according to the embodiments of the disclosure, the driver assistance system and the method thereof can quickly determine cutting out of a preceding vehicle or cutting in of an adjacent vehicle, thereby can improve a performance of a smart cruise control system. 
     Embodiments can thus be implemented through computer readable code/instructions in/on a medium, e.g., a computer readable medium, to control at least one processing element to implement any above described exemplary embodiment. The medium can correspond to any medium/media permitting the storing and/or transmission of the computer readable code. 
     The computer-readable code can be recorded on a medium or transmitted through the Internet. The medium may include read only memory (ROM), random access memory (RAM), magnetic tapes, magnetic disks, flash memories, and optical recording medium. 
     Although embodiments have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the disclosure. Therefore, embodiments have not been described for limiting purposes.