Patent Publication Number: US-2021188259-A1

Title: Driver assistance apparatus and driver assisting 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. 10-2019-0172319, filed on Dec. 20, 2019 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     The present disclosure relates to a driver assistance apparatus, and more particularly, to a driver assistance apparatus capable of avoiding a collision with an object. 
     2. Description of the Related Art 
     Generally, a vehicle refers to a movement device or transportation device, designed to drive on a road or railway using fossil fuel, electric power, and the like as a power source. The vehicle may move to various positions mainly using one or more wheels installed on the vehicle body. Such a vehicle may include a three-wheeled or four-wheeled vehicle, a two-wheeled vehicle, such as a motorcycle, a construction machine, a bicycle, and a train traveling on a railway arranged on a track. 
     Vehicles are the most common means of transportation in modern society, and the number of people using them is increasing. Due to the development of vehicle technology, long-distance movement is easy and life is easier. However, in places with a high population density, road traffic conditions deteriorate and traffic congestion often occurs. 
     Recently, there have been active studies on a vehicle equipped with an advanced driver assist system (ADAS), which actively provides information about the state of a vehicle, the state of a driver, and the surrounding environment to reduce the burden on the driver while enhancing the convenience of the driver. 
     Examples of advanced driver assistance apparatus mounted on vehicles include Forward Collision Avoidance (FCA), Autonomous Emergency Brake (AEB), and Driver Attention Warning (DAW). Such a system is a system for determining the risk of collision with an object in a driving situation of a vehicle, and providing a collision avoidance and warning through emergency braking in a crash situation. 
     The driver assistance apparatus relies on information received from the engine, transmission, braking device and steering device included in the vehicle in connection with the driving of the vehicle. However, when erroneous information is received from the engine, transmission, braking device and steering device, the driver assistance apparatus may malfunction. 
     SUMMARY 
     For the above reasons, an aspect of the present disclosure is to provide a driver assistance apparatus and a driver assisting method capable of identifying forward movement or backward movement of a vehicle based on image data. 
     Therefore, it is an aspect of the present disclosure to provide an apparatus for assisting driving of a host vehicle including: a camera mounted to the host vehicle and having a field of view outside of the host vehicle, the camera configured to obtain image data; and a controller configured to process the image data, identify at least one object obstructing the host vehicle&#39;s driving based on the image data, predict a collision with the at least one object, identify whether the host vehicle is moving forward or backward based on the image data and control a braking device of the host vehicle to brake the host vehicle depending on whether the host vehicle is moving forward or backward. 
     The controller may be configured to control the braking device of the host vehicle to brake the host vehicle in response to the forward movement of the host vehicle. 
     The controller may be configured to control at least one of a display, an audio and a steering wheel of the host vehicle to warn of a collision of the host vehicle in response to the backward movement of the host vehicle. 
     The controller may be configured to identify a stationary object within an image frame by the image data, and identify whether the host vehicle is moving forward or backward based on the movement of the stationary object over time. 
     The controller may be configured to identify at least one of a lane marker and a sign within an image frame by the image data and identify whether the host vehicle is moving forward or backward based on the movement over time of at least one of the lane marker and the sign. 
     The controller may be configured to identify that the host vehicle is moving forward in response to the stationary object moving in a direction from the center of the image frame toward the edge. 
     The controller may be configured to identify that the host vehicle is moving backward in response to the stationary object moving in a direction from the edge of the image frame toward the center. 
     It is another aspect of the present disclosure to provide a method for assisting driving of a host vehicle including: processing an image data obtained by a camera mounted to the host vehicle and having a field of view outside of the host vehicle, having a front field of view of the vehicle; identifying at least one object obstructing the host vehicle&#39;s driving based on the image data; predicting a collision with the at least one object; identifying whether the host vehicle is moving forward or backward based on the image data; and controlling a braking device of the host vehicle to brake the host vehicle depending on whether the host vehicle is moving forward or backward. 
     The controlling a braking device of the host vehicle to brake the host vehicle may include: controlling the braking device of the host vehicle to brake the host vehicle in response to the forward movement of the host vehicle. 
     The driver assistance method may further include: controlling at least one of a display, an audio and a steering wheel of the host vehicle to warn of a collision of the host vehicle in response to the backward movement of the host vehicle. 
     The identifying whether the host vehicle is moving forward or backward may include: identifying a stationary object within an image frame based on the image data; and identifying whether the host vehicle is moving forward or backward based on the movement of the stationary object over time. 
     The identifying a stationary object within an image frame by the image data may include: identifying at least one of a lane marker and a sign within an image frame by the image data. 
     The identifying whether the host vehicle is moving forward or backward based on the movement of the stationary object over time may include: identifying that the host vehicle is moving forward in response to the stationary object moving in a direction from the center of the image frame toward the edge. 
     The identifying whether the host vehicle is moving forward or backward based on the movement of the stationary object over time may include: identifying that the host vehicle is moving backward in response to the stationary object moving in a direction from the edge of the image frame toward the center. 
     The predicting a collision with the at least one object may include: obtaining detection data by sensor installed in the host vehicle, having a detection field of view of at least one of the front and side of the host vehicle in the group including a radar sensor and a lidar sensor; and predicting a collision with the at least one object based on the detection data. 
     It is another aspect of the present disclosure to provide an apparatus for assisting driving of a host vehicle including: an image sensor mounted to the host vehicle and having a field of view outside of the host vehicle, the image sensor configured to obtain image data; a radar sensor mounted to the host vehicle and having a detection field of view of at least one of the front and side of the host vehicle and configured to obtain detection data; and a controller configured to process the image data and the detection data, identify at least one object obstructing the host vehicle&#39;s driving based on the image data, predict a collision with the at least one object based on the detection data, identify whether the host vehicle is moving forward or backward based on the image data and control a braking device of the host vehicle to brake the host vehicle depending on whether the host vehicle is moving forward or backward. 
    
    
     
       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  is a block diagram illustrating a configuration of a vehicle according to an embodiment; 
         FIG. 2  is a block diagram illustrating a configuration of a driver assistance apparatus according to an embodiment; 
         FIG. 3  is a diagram illustrating a field of view of a camera and a radar included in a driver assistance apparatus according to an embodiment; 
         FIG. 4  is a diagram illustrating a method of determining driving of a driver assistance apparatus according to an exemplary embodiment. 
         FIG. 5  is a diagram illustrating an image captured by a camera included in a driver assistance apparatus according to an embodiment. 
         FIG. 6  is a diagram illustrating an emergency braking method of a driver assistance apparatus according to an embodiment. 
         FIG. 7  is a diagram illustrating a vehicle driving forward according to an embodiment. 
         FIG. 8  is a diagram illustrating an image captured by a camera when the vehicle shown in  FIG. 7  is driven. 
         FIG. 9  is a diagram illustrating a vehicle driving backward according to an embodiment. 
         FIG. 10  is a diagram illustrating an image captured by a camera when the vehicle shown in  FIG. 9  is driven. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. Accordingly, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be suggested to those of ordinary skill in the art. The progression of processing operations described is an example; however, the sequence of and/or operations is not limited to that set forth herein and may be changed as is known in the art, with the exception of operations necessarily occurring in a particular order. In addition, respective descriptions of well-known functions and constructions may be omitted for increased clarity and conciseness. 
     Additionally, exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings. The exemplary embodiments may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the exemplary embodiments to those of ordinary skill in the art. Like numerals denote like elements throughout. 
     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. These terms are only used to distinguish one element from another. As used herein, the term “and/or,” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that when an element is referred to as being “connected,” or “coupled,” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected,” or “directly coupled,” to another element, there are no intervening elements present. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the,” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
     The expression, “at least one of a, b, and c,” should be understood as including only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c. 
     Hereinafter, the principles and embodiments of the disclosure will be described with reference to the accompanying drawings. 
       FIG. 1  is a block diagram illustrating a configuration of a vehicle according to an embodiment. 
     As shown in  FIG. 1 , the vehicle  1  includes a driving system  10 , a braking system  30  and a steering system  40 . 
     The driving system  10  moves the vehicle  1 , and includes an engine management system (EMS)  11 , an engine  12 , a transmission control unit (TCU)  21 , and a transmission  22 . 
     The engine  12  may include a cylinder and a piston, and generate power required for the vehicle  1  to drive. The transmission  22  may include a plurality of gears, and transmit the power generated by the engine  12  to wheels. 
     The EMS  11  may control the engine  12  in response to an acceleration intention of the driver through an accelerator pedal or a request of the driver assistance apparatus  100 . For example, the EMS  11  may control the torque of the engine  12 . 
     The TCU  21  may control the transmission  22  in response to a shift command of the driver through a shift lever and/or a driving speed of the vehicle  1 . For example, the TCU  21  may adjust the gear ratio of the engine  12  to the wheels. 
     The braking system  30  stops the vehicle  1  and may include an Electronic Brake Control Module (EBCM)  31  and a braking device  32 . 
     The braking device  32  may decelerate the vehicle  1  or stop the vehicle  1  through friction with the wheel. 
     The EBCM  31  may control the braking device  32  in response to a braking intention of the driver through a braking pedal and/or a slip of the wheels. For example, the EBCM  31  may control the braking device  32  to temporarily release the braking of the wheels in response to a slip of the wheels sensed at a time of braking the vehicle  1  (anti-lock braking systems: ABS). The EBCM  31  may control the braking device  32  to selectively release braking of the wheels in response to over-steering and/or under-steering sensed at a time of steering the vehicle  1  (electronic stability control: ESC). In addition, the EBCM  31  may control the braking device  32  to temporarily brake the wheels in response to a slip of the wheels sensed at a time of driving the vehicle  1  (traction control system: TCS). 
     In addition, the EBCM  31  may control the braking device  32  in response to a request from the driver assistance apparatus  100 . For example, the EBCM  31  may receive a deceleration request including a deceleration rate from the driver assistance apparatus  100  and control the braking device  32  so that the vehicle  1  decelerates depending on the requested deceleration rate. 
     The steering system  40  may include an Electronic Power Steering Control Module (EPS)  41  and a steering device  40 . 
     The steering device  42  may change the driving direction of the vehicle  1 . 
     The EPS  41  may assist the operation of the steering device  42  in response to a steering intention of the driver through the steering wheel such that the driver may easily operate the steering wheel. For example, the EPS  41  may assist the operation of the steering device  42  such that the steering force is reduced during low-speed driving or parking and the steering force is increased during high-speed driving. 
     In addition, the EPS  41  may control the steering apparatus  42  in response to a request from the driver assistance apparatus  100 . For example, the electronic steering control module  41  may receive a steering request including a steering torque from the driver assistance apparatus  100 , and control the steering device  42  to steer the vehicle  1  depending on the requested steering torque. 
     The vehicle  1  further includes a body control module (BCM)  51  and a driver assistance apparatus  100  for driver safety and convenience. 
     The BCM  51  may control the operation of machine parts that provide convenience to the driver or ensure the safety of the driver. For example, the BCM  51  may control a head lamp, a wiper, a cluster, a multifunction switch, a direction indicator lamp, and the like. 
     The driver assistance apparatus  100  may assist the driver in manipulating (driving, braking, and steering) the vehicle  1 . For example, the driver assistance apparatus  100  may sense a surrounding environment of the vehicle  1  (e.g., another vehicle, a pedestrian, a cyclist, a lane, a road sign, and the like), and control driving and/or braking and/or steering of the vehicle  1  in response to the sensed environment. The driver assistance apparatus  100  may provide the driver with various functions. For example, the DAS  100  may include a lane departure warning (LDW), a lane keeping assist (LKA), a high beam assist (HBA), an automatic emergency braking (AEB), a traffic sign recognition (TSR), a smart cruise control (SCC), a blind spot detection (BSD), and the like. 
     The driver assistance apparatus  100  includes a camera module  101  that acquires image data of the surrounding of the vehicle  1  and a radar module  102  that acquires object data of the surrounding of the vehicle  1 . The camera module  101  may include a camera  101   a  and an electronic control unit (ECU)  101   b , and photograph at least one of the front or the lateral side of the vehicle  1  and recognize another vehicle, a pedestrian, a cyclist, a lane, a road sign, and the like. The radar module  102  may include a radar  102   a  and an ECU  102   b , and acquire a relative position, a relative velocity, and the like of an object of the surrounding of the vehicle  1  (e.g., another vehicle, a pedestrian, a cyclists, and the like). 
     The driver assistance apparatus  100  is not limited to the one shown in  FIG. 1 , and may further include a LiDAR that scans around the vehicle  1  and detects an object. 
     The above described electronic components may communicate with each other through vehicle communication network NT. For example, the machine parts may transmit data through Ethernet, media oriented systems transport (MOST), Flexray, controller area network (CAN), local interconnect network (LIN), and the like. For example, the driver assistance apparatus  100  may transmit a driving signal, a braking signal, and a steering signal to the EMS  11 , the TCU  21 , the EBCM  31 , and the EPS  41 , respectively. 
       FIG. 2  is a block diagram illustrating a configuration of a driver assistance apparatus according to an embodiment.  FIG. 3  is a diagram illustrating a field of view of a camera and a radar included in a driver assistance apparatus according to an embodiment. 
     As shown in  FIG. 2 , the vehicle  1  may include a driving system  10 , a braking system  30 , a steering system  40 , and a driver assistance apparatus  100 . 
     The driving system  10 , the braking system  30 , and the steering system  40  may be the same as the driving system  10 , the braking system  30 , and the steering system  40  shown in  FIG. 1 . 
     The driver assistance apparatus  100  may include a front camera  110 , a front radar  120 , and a controller  140 . 
     The front camera  110  may have a field of view  110   a  facing the front of the vehicle  1  as shown in  FIG. 3 . The front camera  110  may be installed, for example, on the front windshield of the vehicle  1 . 
     The front camera  110  may photograph the front of the vehicle  1  and acquire image data of the front of the vehicle  1 . The image data of the front of the vehicle  1  may include position information of another vehicle, a pedestrian, a cyclist, or a lane existing in front of the vehicle  1 . 
     The front camera  110  may include a plurality of lenses and an image sensor. The image sensor may include a plurality of photodiodes for converting light into electrical signals, and the plurality of photodiodes may be arranged in a two-dimensional matrix. 
     The front camera  110  may be electrically connected to the controller  140 . For example, the front camera  110  may be connected to the controller  140  through a vehicle communication network NT, may be connected to the controller  140  through a hard wire, or may be connected to the controller  140  through a printed circuit board (PCB). 
     The front camera  110  may transmit image data in front of the vehicle  1  to the controller  140 . 
     The front radar  120  may have a field of sensing  120   a  facing the front of the vehicle  1  as shown in  FIG. 3 . The front radar  120  may be installed, for example, on a grille or bumper of the vehicle  1 . 
     The front radar  120  may include a transmission antenna (or a transmission antenna array) that radiates transmission radio waves forward of the vehicle  1  and a reception antenna (or a reception antenna array) that receives reflected radio waves reflected from an object. The front radar  120  may acquire front radar data from the transmission radio waves transmitted by the transmission antenna and the reflected radio waves received by the reception antenna. Front radar data may include distance information and velocity information regarding another vehicle, a pedestrian, or a cyclist existing in front of the vehicle  1 . The front radar  120  may calculate the relative distance to the object on the basis of the phase difference (or time difference) between the transmission radio waves and the reflected radio waves, and calculate the relative velocity of the object on the basis of the frequency difference between the transmission radio waves and the reflected radio waves. 
     The front radar  120  may be connected to the controller  140  through a vehicle communication network NT, a hard wire, or a printed circuit board. The front radar  120  may transmit the front radar data to the controller  140 . 
     The controller  140  may include the ECU ( 101   b  in  FIG. 1 ) of the camera module ( 101  in  FIG. 1 ) and/or the ECU ( 102   b  in  FIG. 1 ) of the radar module ( 102  in  FIG. 1 ), and/or an integrated ECU. 
     The controller  140  may be electrically connected to the front camera  110  and the front radar  120 . In addition, the controller  140  may be connected to the driving system  10 , the braking system  30 , and the steering system  40  through a vehicle communication network NT. 
     The controller  140  includes a processor  141  and a memory  142 . 
     The processor  141  may process the front image data of the front camera  110  and the detection data of the front radar  120 , and generate a driving signal, a braking signal and a steering signal for controlling the driving system  10 , the braking system  32  and the steering system  42 . For example, the processor  141  may include an image signal processor for processing front image data of the front camera  110  and/or a digital signal processor for processing radar data of the radars  120 ,  130  and/or a micro control unit (MCU) for generating a driving signal, a braking signal and a steering signal. 
     The processor  141  may sense objects (e.g., another vehicle, a pedestrian, a cyclist, and the like) front of the vehicle  1  on the basis of the front image data of the front camera  110  and the detection data of the front radar  120 . 
     The processor  141  may obtain a position (direction) and classification (eg, whether the object is another vehicle, a pedestrian, or a cyclist) of objects in front of the vehicle  1  based on the image data of the front camera  110 . The processor  141  may obtain the positions (distances and directions) and relative velocity of objects in front of the vehicle  1  based on the detection data of the front radar  120 . In addition, the processor  141  may match objects detected by the image data to objects detected by the detection data, and obtain classification, relative positions, and relative velocity of objects in front of the vehicle  1  based on the matching result. 
     The processor  141  may generate a driving signal, a braking signal, and a steering signal based on the relative positions and relative velocity of the front objects. For example, the processor  141  may transmit a driving signal to the driving system  10  so that the distance to the preceding vehicle (or the time until reaching the position of the preceding vehicle) becomes a distance set by the driver. In addition, the processor  141  calculates a time to collision (TTC) or a distance to collision (DTC) between the vehicle  1  and the front object on the basis of the position (distance) and the relative velocity of the front object, and warns the driver of a collision or transmits a braking signal to the braking system  32  on the basis of a result of comparing the TTC with a reference value. Further, the processor  141  may transmit a steering signal to the steering system  40  in order to avoid a collision with the front object when it is determined that the collision with the front object is based on the time to the collision or the distance to the collision. 
     The processor  141  may select a target having a risk of collision among front objects based on the image data of the front camera  110 . For example, the processor  141  may select another vehicle driving in the same lane as the vehicle  1  as a target. 
     The processor  141  may identify movement of an object other than the target (hereinafter referred to as ‘another object’) based on the image data of the front camera  110 , and may identify whether the vehicle  1  is moving forward or backward based on the movement of the another object. For example, the processor  141  may identify whether the vehicle  1  is moving forward or backward based on the movement of a fixed object (eg, a lane or a sign). 
     The processor  141  may output a braking signal and/or a steering signal for avoiding a collision with a target based on the vehicle  1  moving forward. Also, the processor  141  may output a driving signal for avoiding a collision with a target based on the vehicle  1  moving backward. 
     The memory  142  stores programs and/or data for processing image data by the processor  141 , programs and/or data for processing radar data by the processor  141 , and programs and/or data for generating a driving signal and/or a braking signal and/or a steering signal by the processor  141 . 
     The memory  142  may temporarily store the image data received from the front camera  110  and/or the radar data received from the radars  120  and  130 , and may temporarily store a result of processing the image data and/or the detection data of the processor  141 . 
     The memory  142  may include a volatile memory, such as an S-RAM, a D-RAM, and the like, 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. 
     As such, the controller  140  may transmit a braking signal to the braking system  30  on the basis of whether a collision with the front object is predicted to occur. In addition, the controller  140  may transmit a steering signal to the steering system  40  to avoid a collision with a front object. 
     In addition, when a collision with a target is predicted, the controller  140  may identify whether the vehicle  1  is moving straight forward or backward based on the movement of another object. The controller  140  may output a braking signal and/or a steering signal to avoid a collision with a target when the vehicle  1  is moving straight, and may not output a braking signal and/or a steering signal when the vehicle  1  is moving backward. 
     The driver assistance apparatus  100  is not limited to the one illustrated in  FIG. 2 , and may further include a LiDAR that scans around the vehicle  1  and detects an object. 
       FIG. 4  is a diagram illustrating a method of determining driving of a driver assistance apparatus according to an exemplary embodiment.  FIG. 5  is a diagram illustrating an image captured by a camera included in a driver assistance apparatus according to an embodiment. 
     A method  1000  of determining driving of a driver assistance apparatus will be described with reference to  FIGS. 4 and 5 . 
     The driver assistance apparatus  100  identifies and classifies objects around the vehicle  1  ( 1010 ). 
     While the vehicle  1  is driving or stopped, the front camera  110  of the driver assistance apparatus  100  may acquire image data in front of and/or around the vehicle  1 . The controller  140  of the driver assistance apparatus  100  may acquire image data from the front camera  110 . The controller  140  may identify and classify objects located in front of and/or around the vehicle  1  based on image data. For example, the controller  140  may identify objects including lane markers, signs, another vehicles, pedestrians, bicycles, road boundaries, animals, traffic lights located in front and/or around the vehicle  1 . In addition, the controller  140  may classify the identified object into lane markers, signs, another vehicles, pedestrians, bicycles, road boundaries, animals, traffic lights, and the like. 
     While the vehicle  1  is driving or stopped, the front radar  120  of the driver assistance apparatus  100  may acquire detection data in front of and/or around the vehicle  1 . The controller  140  may acquire detection data from the front radar  120 . The controller  140  may identify objects located in front of and/or around the vehicle  1  based on detection data. 
     The controller  140  may identify objects located in front of and/or around the vehicle  1  depending only on the image data of the front camera  110 , or may identify objects located in front of and/or around the vehicle  1  depending only on detection data of the front radar  120 . 
     In addition, the controller  140  may identify objects located in front of and/or around the vehicle  1  based on image data of the front camera  110  and detection data of the front radar  120 . For example, the controller  140  may identify a common object between objects identified based on the image data of the front camera  110  and the objects identified based on the detection data of the front radar  120 . 
     The driver assistance apparatus  100  may identify the relative position and relative velocity of the surrounding objects of the vehicle  1  ( 1020 ). 
     The controller  140  may identify the relative positions of objects located in front of and/or around the vehicle  1  based on the image data, and may identify relative velocities of objects located in front of and/or around the vehicle  1  based on a plurality of consecutive image data. For example, the controller  140  may identify relative positions of objects based on the position of the object in the image by image data (coordinates of the pixels occupied by the object in the image frame) and the size of the object (the number of pixels occupied by the object in the image frame). In addition, the controller  140  may identify the lateral relative velocity of the objects based on a change in the position of the object in the image by a plurality of consecutive image data (coordinates of the pixel occupied by the object in the image frame), and may identify the longitudinal relative velocity of the objects based on a change in the size of the object (the number of pixels occupied by the object in the image frame). 
     In addition, the controller  140  may identify relative positions and relative velocities of objects located in front of and/or around the vehicle  1  based on detection data. For example, the controller  140  may identify the relative positions of objects located in front of and/or around the vehicle  1  based on the time until the radio wave reflected from the object is received and the angle at which the radio wave is received. In addition, the controller  140  may identify relative velocities of objects located in front of and/or around the vehicle  1  based on a frequency change (Doppler effect) of radio waves reflected from the object. 
     In addition, the controller  140 , based on the image data of the front camera  110  and the detection data of the front radar  120 , may identify the relative position and relative velocity of the object located in front of and/or around the vehicle  1 . For example, the controller  140  may determine the lateral relative position and the lateral relative velocity of the object based on the image data of the front camera  110  and may determine a longitudinal relative position and a longitudinal relative velocity of the object based on detection data of the front radar  120 . Here, the lateral direction indicates a direction perpendicular to the driving direction of the vehicle  1 , and the vertical direction may indicate a direction parallel to the driving direction of the vehicle  1 . 
     The driver assistance apparatus  100  identifies whether the vehicle  1  is moving forward or backward based on the movement of the stationary object ( 1030 ). 
     In general, the driver assistance apparatus  100  may receive driving state information including forward and backward movement from the driving system  20 . For example, the driver assistance apparatus  100  may receive information on the position of the shift lever from the transmission control unit  21  or information on the operation of the transmission  22  (hereinafter referred to as ‘shift information’). However, due to a malfunction of the transmission control unit  21 , the driver assistance apparatus  100  may receive incorrect shift information from the transmission control unit  21 . 
     In order to prevent the driver assistance apparatus  100  from performing an erroneous operation due to receiving incorrect shift information from the transmission control unit  21 , the controller  140  may determine a shift state (eg, forward movement or backward movement of the vehicle) based on the image data acquired by the front camera  110 . 
     In order to determine the shift state of the vehicle  1  (eg, forward movement or backward movement of the vehicle), the controller  140  may identify an object with a fixed position such as a lane marker or sign on the road. For example, the controller  140  may detect a lane marker having a broken line shape from image data using an edge detection algorithm or the like, and detect a sign from the image data using a machine learning technique. 
     The controller  140  may identify whether the vehicle  1  is moving forward or backward based on the movement of the stationary object within the image frame. 
     For example, the controller  140  may receive image data of the image frame  200  as shown in  FIG. 5  from the front camera  110 . The image frame  200  may include a preceding vehicle image  2   a , a lane marker image  3   a , and a sign image  4   a.    
     The controller  140  may identify the preceding vehicle image  2   a , the lane marker image  3   a , and the sign image  4   a  as objects from the image frame  200 , and may identify the relative position and relative velocity of the preceding vehicle image  2   a , the lane marker image  3   a , and the sign image  4   a , respectively. 
     Based on the image frame  200 , the controller  140  may determine that the preceding vehicle is a moving object, and determine that the lane marker and the display panel are stationary objects. In addition, the controller  140  may identify positions (or pixel coordinates) of the lane marker image  3   a  and the sign image  4   a  in the frame. The controller  140  may identify positions (or pixel coordinates) of the lane marker image and the sign image in the next image frame in time of the image frame  200  illustrated in  FIG. 5 . In addition, the controller  140  may identify a change in the position (or pixel coordinate) of the lane marker image  3   a  and the sign image  4   a  in the frame based on the comparison result of the image frame  200  and the next image frame. 
     The controller  140  may identify whether the vehicle  1  is moving forward or backward based on a change in a position (or pixel coordinate) within a frame of the lane marker image  3   a  and the sign image  4   a.    
     For example, when the lane marker image  3   a  and the sign image  4   a  move in the first direction D 1  in which the lane marker image  3   a  and the sign image  4   a  face the edge of the image frame  200  from the center of the image frame  200 , the controller  140  may identify that the vehicle  1  is moving forward. In other words, when the sign image  4   a  located in the right half of the image frame  200  in  FIG. 5  moves further to the right, the controller  140  may determine that the sign is moving away from the vehicle  1  and may also identify that the vehicle  1  is moving forward. In addition, when the lane marker image  3   a  located in the lower left of the image frame  200  in  FIG. 5  moves further to the lower left, the controller  140  may determine that the lane marker is moving away from the vehicle  1  and may also identify that the vehicle  1  is moving forward. 
     In addition, when the size of the sign image  4   a  (the number of pixels occupied by the sign image) increases, the controller  140  may identify that the vehicle  1  is moving forward. 
     As another example, when the lane marker image  3   a  and the sign image  4   a  move in the second direction D 2  in which the lane marker image  3   a  and the sign image  4   a  face the center of the image frame  200  from the edge of the image frame  200 , the controller  140  may identify that the vehicle  1  is moving backward. In other words, when the sign image  4   a  located in the right half of the image frame  200  in  FIG. 5  moves to the left, the controller  140  may determine that the sign is close to the vehicle  1  and may also identify that the vehicle  1  is moving backward. In addition, when the lane marker image  3   a  located in the lower left of the image frame  200  in  FIG. 5  moves to the lower right, the controller  140  may determine that the lane marker is close to the vehicle  1  and may also identify that the vehicle  1  is moving backward. 
     In addition, when the size of the sign image  4   a  (the number of pixels occupied by the sign image) decreases, the controller  140  may identify that the vehicle  1  is moving backward. 
     As described above, the driver assistance apparatus  100  may identify whether the vehicle  1  is moving forward or backward based on image data acquired by the front camera  110 . 
     Thereby, in spite of the malfunction of the transmission control device  21 , the driver assistance apparatus  100  may identify whether the vehicle  1  is moving forward or backward. 
       FIG. 6  is a diagram illustrating an emergency braking method of a driver assistance apparatus according to an embodiment.  FIG. 7  is a diagram illustrating a vehicle driving forward according to an embodiment.  FIG. 8  is a diagram illustrating an image captured by a camera when the vehicle shown in  FIG. 7  is driven.  FIG. 9  is a diagram illustrating a vehicle driving backward according to an embodiment.  FIG. 10  is a diagram illustrating an image captured by a camera when the vehicle shown in  FIG. 9  is driven. 
     Together with  FIGS. 6, 7, 8, 9 and 10 , the emergency braking method  1100  of the driver assistance apparatus will be described. 
     The driver assistance apparatus  100  identifies and classifies objects around the vehicle  1  ( 1110 ). The driver assistance apparatus  100  identifies the relative position and relative velocity of the surrounding objects of the vehicle  1  ( 1120 ). 
     Operations  1110  and  1120  may be the same as operations  1010  and  1020  shown in  FIG. 4 . 
     The driver assistance apparatus  100  selects a target among objects ( 1130 ). 
     The controller  140  may select a target having a risk of collision with the vehicle  1  based on image data acquired by the front camera  110 . 
     For example, the controller  140  may identify a lane marker and another vehicle based on image data of the front camera  110 . The controller  140  may identify a preceding vehicle driving in the same lane as the vehicle  1  among another vehicles based on the lane marker and the position of the another vehicle. The controller  140  may identify a lane in which the vehicle  1  drives based on the position of the lane marker, and may identify a preceding vehicle driving in the same lane as the vehicle  1  based on the positions of another vehicles. In addition, the controller  140  may select a preceding vehicle as a target. 
     As another example, the controller  140  may determine an object (eg, a preceding vehicle, a pedestrian, a bicycle, or an animal) that is expected to collide with the vehicle  1  based on the relative position and relative velocity of the objects. The controller  140  may select an object that is expected to collide with the vehicle  1  as a target. 
     The driver assistance apparatus  100  determines whether the time until the collision with the target is less than the reference time ( 1140 ). 
     The controller  140  may predict a time to collision (TTC) between the vehicle  1  and the target based on the relative positions and relative velocity of the objects. For example, the controller  140  may calculate the remaining time to collision (TTC) between the vehicle  1  and the preceding vehicle based on the distance to the preceding vehicle and the relative velocity of the preceding vehicle. The controller  140  may also compare the remaining time to collision (TTC) with the target with the reference time, and determine whether the remaining time to collision (TTC) with the target is less than the reference time. 
     However, operation  1140  may be replaced with an operation dependent on distance. 
     For example, the controller  140  may predict a distance to collision (DTC) between the vehicle  1  and the target based on the relative positions and relative velocity of the objects. The controller  140  may calculate the distance to collision (DTC) with the target based on the product of the driving speed of the vehicle  1  and the remaining time to collision (TTC) with the target. The controller  140  may also compare the remaining distance to collision (DTC) with the target with the reference time, and determine whether the remaining distance to collision (DTC) with the target is less than the reference distance. 
     When the time to collision with the target is not less than the reference time (No in  1140 ), the driver assistance apparatus  100  may re-identify surrounding objects and re-identify the relative positions and relative velocity of the objects. In addition, the driver assistance apparatus  100  may reselect the target and determine whether the time to the collision with the target is less than the reference time. 
     When the time to the collision with the target is less than the reference time (YES in  1140 ), the driver assistance apparatus  100  determines whether the vehicle  1  is moving forward or backward ( 1150 ). 
     The controller  140  may determine whether the vehicle  1  is moving forward or backward based on the image data of the front camera  110  as described above with reference to  FIG. 4 . For example, the controller  140  may determine whether the vehicle  1  is moving forward or backward based on the movement of an image representing a stationary object within an image frame captured by the front camera  110 . Specifically, the controller  140  may determine that the vehicle  1  moves forward when the image of the stationary object in the image frame moves from the center of the image frame toward the edge. Further, the controller  140  may determine that the vehicle  1  moves backward when the image of the stationary object in the image frame moves from the edge of the image frame toward the center. 
     When it is determined that the vehicle  1  is moving forward (“moving forward” in  1150 ), the driver assistance apparatus  100  performs emergency braking ( 1160 ). 
     When a collision between vehicle  1  and target is expected and vehicle  1  moves forward, it may be determined that the vehicle  1  moves toward a target (eg, a preceding vehicle). 
     For example, as shown in  FIG. 7 , the preceding vehicle  2  may be located in front of the vehicle  1 . In addition, a lane marker  3  may be located on the left side of the vehicle  1 , and a sign  4  may be located on the front right side of the vehicle  1 . 
     In this case, the front camera  110  may capture an image frame  210  as shown in  FIG. 8 . The image frame  210  may include a preceding vehicle image  2   a  representing the preceding vehicle  2 , a lane marker image  3   a  representing the lane marker  3 , and a sign image  4   a  representing the sign  4 . 
     When the preceding vehicle  2  stops and the vehicle  1  drives forward, in the image frame  210  captured by the front camera  110 , the preceding vehicle image  2   a  increases, and the remaining time to collision (TTC) between the vehicle  1  and the preceding vehicle  2  may decrease. The controller  140  may predict a collision between the vehicle  1  and the preceding vehicle  2 . In addition, as shown in  FIG. 8 , the lane marker image  3   a  and/or the sign image  4   a  in the image frame  210  may move from the center of the image frame  210  toward the edge. 
     The controller  140  may determine that the vehicle  1  is driving toward the front based on the movement of the lane marker image  3   a  and/or the sign image  4   a . In addition, the controller  140  may determine that a collision between the vehicle  1  and the preceding vehicle  2  is expected because the vehicle  1  advances toward the preceding vehicle  2 . 
     Accordingly, the controller  140  may brake the vehicle  1  in order to avoid a collision between the vehicle  1  and the preceding vehicle  2 . For example, based on the remaining time to collision (TTC) between the vehicle  1  and the preceding vehicle  2 , the controller  140  prepares for braking and then brakes the vehicle  1  with the first braking force and then may transmit a braking signal to the braking system  30  to brake the vehicle  1  with a second braking force greater than the first braking force. 
     When it is determined that the vehicle  1  is moving backward (“moving backward” of  1150 ), the driver assistance apparatus  100  warns of a collision ( 1170 ). 
     When a collision between the vehicle  1  and the target is expected and the vehicle  1  moves backward, it may be determined that the target (eg, a preceding vehicle) moves toward the vehicle  1 . 
     For example, as shown in  FIG. 9 , the vehicle  1  may drive backward, and the preceding vehicle  2  may also drive backward in front of the vehicle  1 . In addition, a lane marker  3  may be located on the left side of the vehicle  1 , and a sign  4  may be located on the front right side of the vehicle ( 1 ). 
     In this case, the front camera  110  may capture an image frame  220  as shown in  FIG. 10 . The image frame  220  may include a preceding vehicle image  2   a  representing the preceding vehicle  2 , a lane marker image  3   a  representing the lane marker  3 , and a sign image  4   a  representing the sign  4 . 
     When vehicle  1  drives backward and the preceding vehicle  2  drives backward at a faster speed, in the image frame  210  captured by the front camera  110 , the preceding vehicle image  2   a  increases, and the remaining time to collision (TTC) between the vehicle  1  and the preceding vehicle  2  may decrease. The controller  140  may predict a collision between the vehicle  1  and the preceding vehicle  2 . In addition, as illustrated in  FIG. 10 , the lane marker image  3   a  and/or the sign image  4   a  in the image frame  220  may move from the edge of the image frame  220  toward the center. 
     The controller  140  may determine that the vehicle  1  is driving toward the rear based on the movement of the lane marker image  3   a  and/or the sign image  4   a . In addition, the controller  140  may determine that a collision between the vehicle  1  and the preceding vehicle  2  is expected because the preceding vehicle  2  moves backward toward the vehicle  1 . 
     If it is determined that a collision between the vehicle  1  and the preceding vehicle  2  is expected, and thus the vehicle  1  is braked, a collision between the vehicle  1  and the preceding vehicle  2  may be caused. 
     Accordingly, the controller  140  may provide a warning message to the driver to avoid a collision between the vehicle  1  and the preceding vehicle  2 . For example, based on the remaining time to collision (TTC) between vehicle  1  and preceding vehicle  2 , the controller  140  may display an image warning message on a display (eg, cluster, AVN, etc.) of the vehicle  1  or may output an acoustic warning message through audio (eg, AVN) of the vehicle  1  or a tactile warning message through a steering wheel of the vehicle  1 . 
     As described above, the driver assistance apparatus  100  may predict a collision with a target (for example, a preceding vehicle), and may identify whether the vehicle  1  is moving forward or backward based on the image data acquired by the front camera  110 . In addition, the driver assistance apparatus  100  may urgently brake the vehicle  1  when the vehicle  1  moves forward, and warn of a collision of the vehicle  1  when the vehicle  1  moves backward. 
     Thereby, a collision with the preceding vehicle  2  may be prevented due to the emergency braking of the vehicle  1  while the vehicle  1  moves backward. 
     An aspect of the present disclosure is to provide a driver assistance apparatus and a driver assisting method capable of identifying forward movement or backward movement of a vehicle based on image data. 
     Exemplary embodiments of the present disclosure have been described above. In the exemplary embodiments described above, some components may be implemented as a “module”. Here, the term ‘module’ means, but is not limited to, a software and/or hardware component, such as a Field Programmable Gate Array (FPGA) or Application Specific Integrated Circuit (ASIC), which performs certain tasks. A module may advantageously be configured to reside on the addressable storage medium and configured to execute on one or more processors. 
     Thus, a module may include, by way of example, components, such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The operations provided for in the components and modules may be combined into fewer components and modules or further separated into additional components and modules. In addition, the components and modules may be implemented such that they execute one or more CPUs in a device. 
     With that being said, and in addition to the above described exemplary embodiments, 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), Compact Disk-Read Only Memories (CD-ROMs), magnetic tapes, floppy disks, and optical recording medium. Also, the medium may be a non-transitory computer-readable medium. The media may also be a distributed network, so that the computer readable code is stored or transferred and executed in a distributed fashion. Still further, as only an example, the processing element could include at least one processor or at least one computer processor, and processing elements may be distributed and/or included in a single device. 
     While exemplary embodiments have been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope as disclosed herein. Accordingly, the scope should be limited only by the attached claims.