Patent Publication Number: US-9895974-B2

Title: Vehicle control apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 U.S.C. §119 to Japanese Patent Application 2014-176069, filed on Aug. 29, 2014, the entire content of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     This disclosure generally relates to a vehicle control apparatus. 
     BACKGROUND DISCUSSION 
     A known technology for supporting parking of a vehicle is disclosed in JP2013-210225A (hereinafter referred to as Patent reference 1). According to the technology disclosed in Patent reference 1, a driver receives an image data captured by plural cameras mounted on the vehicle, the image data captured as surroundings of the vehicle. Patent reference 1 further offers a technology that warns the driver in accordance with an inclination of the vehicle. 
     However, according to the technology disclosed in Patent reference 1, the driver may not recognize the inclination of the vehicle by watching only the image data captured by a camera mounted on the vehicle. Further, because the warning in accordance with the inclination of the vehicle is performed at a predetermined timing, it is difficult for the driver to recognize the inclination of the vehicle at other timing than the predetermined timing. 
     A need thus exists for a vehicle control apparatus which is not susceptible to the drawback mentioned above. 
     SUMMARY 
     According to an aspect of this disclosure, a vehicle control apparatus includes a first acquisition portion acquiring a captured image data outputted from an imaging portion that is provided at a vehicle and that images a surrounding of the vehicle, a second acquisition portion acquiring an inclination angle of the vehicle on a basis of a state information of the vehicle, the state information outputted from a vehicle state detection portion that is provided at the vehicle, and an output portion being configured to output an output image data to a display device, the output image data including the captured image data and an inclination angle display information indicating the inclination angle of the vehicle, the output portion changing a display method within the output image data in accordance with the inclination angle of the vehicle and outputting the output image data. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and additional features and characteristics of this disclosure will become more apparent from the following detailed description considered with the reference to the accompanying drawings, wherein: 
         FIG. 1  is a perspective view illustrating an example of a state where a portion of an interior of a vehicle according to an embodiment is viewed in a perspective manner; 
         FIG. 2  is a plan view (bird&#39;s eye view) illustrating an example of the vehicle according to the embodiment; 
         FIG. 3  is a block diagram illustrating an example of a surroundings monitoring system of the vehicle according to the embodiment; 
         FIG. 4  is a view illustrating an example of a detection direction of an acceleration sensor according to the embodiment; 
         FIG. 5  is a block diagram illustrating a construction of a surroundings monitoring portion realized within a surroundings monitoring ECU according to the embodiment; 
         FIG. 6  is an example of captured image data captured by an imaging portion according to the embodiment. 
         FIG. 7  is a diagram illustrating an example of a two-dimensional orthogonal coordinate system that indicates a display region of the captured image data in a case where a position coordinate corresponding to a center of a lens serves as an origin; 
         FIG. 8  is a diagram illustrating an example of the captured image data after a rotation correction is performed by a rotation control portion according to the embodiment; 
         FIG. 9  is a diagram illustrating an example of image data after a composition portion performs composition according to the embodiment; 
         FIG. 10  is a flowchart illustrating procedures of a display processing on a display device in a surroundings monitoring portion according to the embodiment; 
         FIG. 11  is a flowchart illustrating procedures of a composition processing of an image data that is displayed on a display device in a surroundings monitoring portion according to the embodiment; 
         FIG. 12  is a view illustrating an example of an output image data after the composition portion performs composition according to the embodiment; 
         FIG. 13  is a view illustrating another example of the output image data after the composition portion performs composition according to the embodiment; 
         FIG. 14  is a view illustrating an example of an output image data after the composition portion performs composition according to a first modified example of the embodiment; and 
         FIG. 15  is a view illustrating an example of an output image data after the composition portion performs composition according to a second modified example of the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The following embodiment and modified examples include the similar components to one another. Thus, the similar components bear the common reference numerals. In addition, duplicated explanation is omitted. 
     In the embodiment, a vehicle  1  may be a car (internal combustion car) including an internal combustion engine as a driving source, a car (an electric car and a fuel cell car, or the like) including an electric motor as the driving source, or a car (a hybrid car) including the engine and the motor as the driving sources, for example. In addition, the vehicle  1  may include various kinds of transmissions and various kinds of apparatuses (systems. Parts and the like) desired for driving the internal combustion engine or the electric motor. Further, method, quantity, layout and the like of an apparatus related to driving of wheels  3  of the vehicle  1  may be variously specified. 
     As illustrated in  FIG. 1 , a vehicle body  2  forms a vehicle interior  2   a  where a passenger gets in. For example, a steering portion  4 , an acceleration operating portion  5 , a braking operating portion  6 , a speed change operating portion  7  and the like are provided within the vehicle interior  2   a  in a state facing a seat  2   b  of a driver as the passenger. In the embodiment, as an example, the steering portion  4  is a steering wheel projecting from a dashboard (instrument panel) and the acceleration operating portion  5  is an accelerator pedal positioned at the feet of the driver. The braking operating portion  6  is a brake pedal positioned at the feet of the driver and the speed change operating portion  7  is a shift lever projecting from a center console. Nevertheless, the steering portion  4 , the acceleration operating portion  5 , the braking operating portion  6  and the speed change operating portion  7  are not limited to the aforementioned members. 
     In addition, a display device  8  (display output portion) and an audio output device  9  (audio output portion) are provided within the vehicle interior  2   a . The display device  8  is, for example, a LCD (liquid crystal display), an OELD (organic electroluminescent display) and the like. The audio output device  9  is, as an example, a speaker. In the embodiment, the display device  8  is covered by a clear operation input portion  10  (for example, a touch panel and the like), for example. The passenger and the like may visually confirm a projected image (image) on a display screen of the display device  8  via the operation input portion  10 . The passenger and the like may perform an operation input (instruction input) by operating the operation input portion  10 , i.e., touching, pressing or moving the operation input portion  10  with one&#39;s finger at a position corresponding to the projected image (image) displayed on the display screen of the display device  8 . In the embodiment, as an example, the display device  8 , the audio output device  9 , the operation input portion  10  and the like are provided at a monitor device  11  positioned at a center portion of the dashboard in a vehicle width direction (right-left direction). The monitor device  11  may include an operation input portion such as a switch, a dial, a joy-stick and a pressing button, for example. An audio output device may be provided at other position within the vehicle interior  2   a , i.e., position different from the monitor device  11 . In addition, sound may be output from other audio output device than the audio output device  9  of the monitor device  11 . In the embodiment, as an example, the monitor device  11  is shared by a navigation system and an audio system. Alternatively, a monitor device of a surroundings monitoring apparatus may be separately provided from the aforementioned systems. It may be configured that, in addition to the audio output device  9 , a warning sound and the like may be output from an audio output portion such as a buzzer  24  (refer to  FIG. 3 ), for example. 
     As illustrated in  FIGS. 1 and 2 , in the embodiment, the vehicle  1  is a four-wheel vehicle (four-wheel car) as an example. The vehicle  1  includes two right and left front wheels  3 F and two right and left rear wheels  3 R. Further, in the embodiment, these four wheels  3  are configured to be steered (steerable). Specifically, as illustrated in  FIG. 3 , the vehicle  1  includes a wheel steering system  12  steering the front wheels  3 F or the rear wheels  3 R. The wheel steering system  12  may steer the front wheels  3 F and the rear wheels  3 R simultaneously, or at the same time. 
     In the embodiment, as an example, plural (in the embodiment, four, as an example) imaging portions  16  ( 16   a ,  16   b ,  16   c ,  16   d ) are provided at the vehicle  1  (vehicle body  2 ) as illustrated in  FIG. 2 . Each of the imaging portions  16  is, for example, a digital camera incorporating an imaging element such as a CCD (charge coupled device), a CIS (CMOS image sensor) and the like. The imaging portions  16  may output image data (moving image data, frame data) at a predetermined frame rate. Each of the imaging portions  16  includes a wide-angle lens to thereby take a picture in a range from, for example, 140 degrees to 220 degrees in a lateral direction or in a horizontal direction (view angle). An optical axis of the imaging portion  16  is specified to face downward (obliquely downward). Thus, the imaging portion  16  takes a picture of outside environment around the vehicle body  2  including a road surface on which the vehicle  1  is movable. 
     In the above, the lateral direction is a direction included in a lateral plane orthogonal to a direction of gravity (vertical direction). 
     In the embodiment, as an example, the imaging portion  16   a  is positioned at an end portion  2   c  (an end portion in a plan view) at a front side (a front side in a vehicle front-rear direction) of the vehicle body  2  and is provided at a front bumper, for example. The imaging portion  16   b  is positioned at an end portion  2   d  at a left side (a left side in a vehicle width direction) of the vehicle body  2  and is provided at a door mirror  2   g  (projecting portion) at a left side. The imaging portion  16   c  is positioned at an end portion  2   e  at a rear side (a rear side in the vehicle front-rear direction) of the vehicle body  2  and is provided at a wall portion at a lower side of a door  2   h  of a rear trunk. The imaging portion  16   d  is positioned at an end portion  2   f  at a right side (a right side in the vehicle width direction) of the vehicle body  2  and is provided at a door mirror  2   g  (projecting portion) at a right side. In the embodiment, the method of mounting the camera at the vehicle is not limited and the camera may be mounted so that the image data in a front direction, the image data in right and left side directions and the image data in a rear direction relative to the vehicle is obtainable. 
     The surroundings monitoring ECU  14  performs a calculation processing and an image processing based on the image data obtained by the plural imaging portions  16 . The surroundings monitoring ECU  14  generates a wider view angle image and a virtual bird&#39;s eye view image (planar image) where the vehicle  1  (vehicle body  2 ) is viewed from an upper side. 
     In the embodiment, as an example, in a surroundings monitoring system  100  as illustrated in  FIG. 3 , a brake system  18 , a steering angle sensor  19  (angular sensor), an accelerator sensor  20 , a shift sensor  21 , a wheel speed sensor  22 , an acceleration sensor  26  (i.e., serving as a vehicle state detection portion), and the like are electrically connected, in addition to the surroundings monitoring ECU  14 , the monitor device  11 , the front wheel steering system  12 , the rear wheel steering system  13 , and the like, via an in-vehicle network  23  (electric telecommunication line). The in-vehicle network  23  is configured as a CAN (controller area network) as an example. The surroundings monitoring ECU  14  may send a control signal via the in-vehicle network  23  to control the front wheel steering system  12 , the rear wheel steering system  13 , the brake system  18 , and the like. The surroundings monitoring ECU  14  may also receive detection results of a torque sensor  12   b , a tire angle sensor  13   b  (for the rear wheels  3 R), an actuator  18   a , a brake sensor  18   b , the steering angle sensor  19  (for the front wheels  3 F), the accelerator sensor  20 , the shift sensor  21 , the wheel speed sensor  22 , the acceleration sensor  26 , and the like and indicator signals (control signals, operation signals, input signals, data) of the operation input portion  10  and the like via the in-vehicle network  23 . 
     In the embodiment, the two acceleration sensors  26  ( 26   a ,  26   b ) are provided at the vehicle  1 . In the embodiment, the vehicle  1  is equipped with an ESC (electronic stability control). Then, the acceleration sensors  26  ( 26   a ,  26   b ) as conventionally mounted to the vehicle equipped with the ESC (electronic stability control) are employed. In the embodiment, no restriction is made on the acceleration sensor. The sensor that detects the acceleration in the right-left direction of the vehicle  1  is acceptable. 
       FIG. 4  is a diagram illustrating an example of detection directions of the acceleration sensors  26   a ,  26   b . A detection direction  401  is the detection direction of the acceleration sensor  26   a  while a detection direction  402  is the detection direction of the acceleration sensor  26   b . The detection direction  401  illustrated in  FIG. 4  corresponds to a direction inclined by 45 degrees from a travelling direction (front-rear direction) of the vehicle  1  on a plane in parallel with a ground (a plane on which the vehicle  1  is movable). The detection direction  402  forms an angle of 90 degrees relative to the detection direction  401  on the plane in parallel with the ground. Because the two different detection directions are provided on the plane in parallel with the ground, the acceleration in the front-rear direction and the acceleration in the right-left direction may be obtained. In the embodiment, no restriction is made on the detection direction and at least the acceleration in the right-left direction may be obtained. Calculations of the acceleration in the front-rear direction and the acceleration in the right-left direction are made at the surroundings monitoring ECU  14 . 
     The front-rear direction of the vehicle  1  indicates the travelling direction and an opposite direction from the travelling direction of the vehicle  1 . The right-left direction of the vehicle  1  is a direction included in a surface orthogonal to the travelling direction of the vehicle  1 . 
     Back to  FIG. 3 , the surroundings monitoring ECU  14  includes, as an example, a CPU  14   a  (central processing unit), a ROM  14   b  (read only memory), a RAM  14   c  (random access memory), a display control portion  14   d , an audio control portion  14   e , a SSD  14   f  (solid state drive, flush memory), and the like. The CPU  14   a  performs the image processing related to the image displayed at the display device  8  and the various calculation processing such as calculation of a moving path of the vehicle  1  and determination of whether or not interference with an object occurs, for example. The CPU  14   a  reads out program stored (installed) at a nonvolatile memory device such as the ROM  14   b , for example, and performs the calculation processing based on the aforementioned program. 
     The RAM  14   c  temporarily stores various data used for the calculations at the CPU  14   a . The display control portion  14   d  mainly performs the image processing using the image data obtained at the imaging portions  16  and the image processing (composition and the like, as an example) of the image data displayed at the display device  8 , for example, within the calculation processing at the surroundings monitoring ECU  14 . In addition, the audio control portion  14   e  mainly performs processing of audio data output at the audio output device  9  within the calculation processing at the surroundings monitoring ECU  14 . The SSD  14   f  is a rewritable nonvolatile memory portion that stores data even in a case where a power source of the surroundings monitoring ECU  14  is turned off. The CPU  14   a , the ROM  14   b , the RAM  14   c  and the like may be integrated within the same package. The surroundings monitoring ECU  14  may be configured to include other logic operation processor such as a DSP (digital signal processor) or a logic circuit, for example, than the CPU  14   a . In addition, instead of the SSD  14   f , a HDD (hard disk drive) may be provided. Further, the SSD  14   f  or the HDD may be provided separately from the surroundings monitoring ECU  14 . 
       FIG. 5  is a block diagram illustrating a construction of a surroundings monitoring portion  500  realized within the surroundings monitoring ECU  14  according to the embodiment. Each construction within the surroundings monitoring portion  500  illustrated in  FIG. 5  is realized in a case where the CPU  14   a  configured as the surroundings monitoring ECU  14  in  FIG. 4  performs software stored within the ROM  14   b.    
     The surroundings monitoring portion  500  realizes an acquisition portion  501  (i.e., serving as a first acquisition portion), an angle calculation portion  502  (i.e., serving as a second acquisition portion), a filtering control portion  503 , an image processing portion  504  and an output portion  505  by performing software stored within the ROM  14   b  (computer readable storage medium). At this time, software (program) may be provided via other computer readable storage medium. 
     Then, the surroundings monitoring portion  500  according to the embodiment assists the driving of the driver by displaying the image data by which a state around the vehicle  1  is recognizable on the basis of the captured image data input from the imaging portions  16  in a case where the vehicle  1  moves to be parked, and the acceleration data as an example of a vehicle state data acquired by the acceleration sensor  26  (acceleration detection portion) functioning as an example of a vehicle state detection portion. 
     The acquisition portion  501  acquires various pieces of information from various sensors, for example, provided at the vehicle  1 . The acquisition portion  501  according to the embodiment acquires the captured image data output from the imaging portions  16   a  to  16   d  provided at the vehicle  1  to capture the images in the surroundings of the vehicle  1  and the acceleration data output from the acceleration sensors  26   a ,  26   b  provided at the vehicle  1 . Further, the acquisition portion  501  acquires information indicating whether or not a mode specified by a switch provided at the operation input portion  10  is an off-road mode. The acquisition portion  501  outputs the acquired information to the angle calculation portion  502  and the image processing portion  504 . 
     The acquisition portion  501  also correlates the captured image data with the acceleration data where time when the image is captured in the captured image data and time when the acceleration is detected in the acceleration data substantially match each other. 
     The angle calculation portion  502  calculates an inclination angle (a pitch angle and a roll angle) of the vehicle  1  based on the acceleration data acquired by the acceleration sensors  26   a ,  26   b  that is an example of the vehicle state detection portion mounted to the vehicle  1 . In the embodiment, an example of calculating the inclination angle of the vehicle  1  in response to the acceleration data outputted by the acceleration sensors  26   a ,  26   b  will be explained. Alternatively, any method can be applied as long as obtaining the inclination angle of the vehicle  1 . 
     The pitch angle (i.e., serving as a second inclination angle) is an angle indicating an inclination of the surroundings of a lateral axis (an axis  412  in  FIG. 4 ) of the vehicle  1 . In a case where the vehicle  1  is present on the lateral plane (ground), the roll angle (i.e., serving as a first inclination angle) is zero degrees. 
     The roll angle is an angle indicating an inclination of the vehicle  1  around a longitudinal axis (axis  411  in  FIG. 4 ) of the vehicle  1 . In a case where the vehicle  1  is present on the lateral plane (ground), the roll angle is zero degrees. In order to calculate the pitch angle and the roll angle, the angle calculation portion  502  first calculates an acceleration a 1  in the front-rear direction and an acceleration a 2  in the right-left direction of the vehicle  1 . 
     The angle calculation portion  502  calculates the acceleration a 1  in the front-rear direction using the following equation (1). The acceleration in the detection direction  401  is specified to be GL 1  and the acceleration in the detection direction  402  is specified to be GL 2 . The pitch angle is calculated from the acceleration a 1  in the front-rear directions and from the acceleration of gravity. The roll angle is calculated from the acceleration a 2  in the right-left directions and the acceleration of gravity.
 
 a 1= GL 1×cos 45 °−GL 2×cos 45°  (1)
 
     Next, the angle calculation portion  502  calculates the acceleration a 2  in the right-left direction using the following equation (2).
 
 a 2=−( GL 1×sin 45°+ GL 2×)sin 45°  (2)
 
     Further, the angle calculation portion  502  calculates a pitch angle PA using the following equation (3).
 
PA=sin −1 ( a 1/1 G )  (3)
 
     Further, the angle calculation portion  502  calculates a roll angle RA using the following equation (4).
 
RA=sin −1 ( a 2/1 G )  (4)
 
     The angle calculation portion  502  correlates the roll angle and the pitch angle calculated from the acceleration data with the captured image data that is correlated to the aforementioned acceleration data. Accordingly, the roll angle and the pitch angle of the vehicle  1  when the captured image data is captured are recognizable. 
     The filtering control portion  503  performs filtering by low-pass filter relative to the roll angle RA and the pitch angle PA calculated by the angle calculation portion  502 . 
     In the embodiment, steep changes of the roll angle RA and the pitch angle PA, in other words, a steep switching of the image data displayed at the display device  8  is restrained by performing the low-pass filter. Accordingly, the driver may comfortably watch the image data displayed at the display device  8 . In the embodiment, an example where digital filter is used by the filtering control portion  503  provided within the surroundings monitoring portion  500  is explained. Nevertheless, for example, analog filter, for example, may be performed relative to a signal output from the acceleration sensor  26 . 
     The image processing portion  504  includes a rotation control portion  521 , a reduction/enlargement control portion  522 , a movement control portion  523  and a composition portion  524  to generate the image data displayed at the display device  8 . 
     The rotation control portion  521  performs a rotation correction on the captured image data capturing the surroundings of a front side of the vehicle  1 . A subject of the rotation correction is not limited to the captured image data captured by the imaging portion  16   a  and may be the captured image data captured by the imaging portion  16   c  capturing the surroundings of a rear side of the vehicle  1 , for example. 
       FIG. 6  is an example of the captured image data captured by the imaging portion  16   a . The captured image data illustrated in  FIG. 6  is captured from the vehicle  1  that is inclined. The driver tends to recognize the image displayed at the display device  8  in an objective way and thus tends to recognize areas in the captured image data displayed at the display device  8 , in a case where the areas include the same heights in a vertical axis direction, include the same heights in reality or heights with a smaller height difference than the actual height difference. In the example illustrated in  FIG. 6 , a region  601  and a region  602  are possibly recognized as the same heights. 
     Thus, the rotation control portion  521  according to the embodiment performs the rotation correction on the captured image data depending on the roll angle obtained by the acceleration sensors  26 . In other words, the rotation control portion  521  performs the rotation correction (control) on the captured image data based on the inclination of the vehicle in the right-left direction relative to the lateral direction serving as the direction included in the lateral plane orthogonal to the direction of gravity calculated from the vehicle state data. For example, the rotation control portion  521  performs the rotation correction (control) so that a lateral line included in a subject captured in the captured image data is substantially parallel to a lateral-direction side at a display region of an output destination. 
     The rotation control portion  521  according to the embodiment performs the rotation correction with an origin at a position coordinate within the display region of the captured image data corresponding to a center of a lens used by the imaging portion  16  for image capturing depending on the roll angle correlated to the aforementioned captured image data. 
       FIG. 7  is a diagram illustrating an example of a two-dimensional orthogonal coordinate system that indicates the display region of the captured image data in a case where the position coordinate corresponding to the center of the lens serves as the origin. For each position coordinate included in the coordinate system illustrated in  FIG. 7 , the rotation control portion  521  converts the position coordinate by an equation (5) indicated below so as to achieve the rotation correction of the captured image data. Here, dx0, dy0 is a coordinate value with the origin at the center of the lens. In addition, θ is the roll angle that is calculated. 
     
       
         
           
             
               
                 
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       FIG. 8  is a diagram illustrating an example of the captured image data obtained after the rotation correction is performed by the rotation control portion  521 . In the example illustrated in  FIG. 8 , the rotation correction is performed so that the lateral line included in the subject (environment outside the vehicle  1 ) captured in the captured image data is substantially in parallel with the lateral-direction side of the display region of the display device  8 . In other words, the rotation correction is performed so that a lower direction of the captured image data corresponds to the direction of gravity of the subject (environment outside the vehicle  1 ) captured in the aforementioned captured image data. At this time, the lower direction and the direction of gravity do not necessarily completely coincide with each other and may coincide with each other so that a height relation within the captured image data is recognizable. 
     For example, as for the region  601  and the region  602  which seem to include the same heights in  FIG. 6 , it is recognizable in  FIG. 8  that the region  602  is present at a higher position than the region  601 . Therefore, the driver may recognize an objective height in the surrounding environments of the vehicle  1 . Accordingly, an appropriate driving is achievable, which may improve safety. 
     The reduction/enlargement control portion  522  functioning as the control portion performs an enlargement processing or a reduction processing relative to the captured image data after the rotation correction is performed by the rotation control portion  521 . The reduction/enlargement control portion  522  converts the position coordinate by an equation (6) indicated below to achieve an enlargement correction or a reduction correction of the captured image data. Here, dx1, dy1 is a coordinate value with the origin at the center of the lens after the rotation correction is performed. Here, magX and magY are lateral and vertical enlargement/reduction rates. The enlargement/reduction rate is decided on a basis of a relationship between a display size of the captured image data and number of pixels of the display region of the display device  8 . 
     
       
         
           
             
               
                 
                   
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     The movement control portion  523  functioning as the control portion performs a control on the captured image data after the enlargement or reduction processing is performed by the reduction/enlargement control portion  522  so that the position coordinate corresponding to the center of the lens moves from the center of the display region of the display device  8 . In the embodiment, the movement control portion  523  performs a control to move the position coordinate corresponding to the center of the lens from the center of the display region of the display device  8  to an upper direction within the display region. 
     That is, in a situation where the vehicle  1  is inclined, the driver tends to desire to confirm the ground conditions. Thus, the movement control portion  523  performs the processing to move the position coordinate corresponding to the center of the lens from the center of the display region of the display device  8  to the upper direction within the display region. Accordingly, conditions upper than the vehicle  1  such as the sky captured in the captured image data, for example, are not displayed and conditions lower than the vehicle  1  are displayed. Thus, the user may recognize the ground conditions around the vehicle  1  by referring to the captured image data displayed at the display device  8 . Accordingly, an appropriate steering assist is achievable. 
     The movement control portion  523  converts the position coordinate by an equation (7) indicated below to achieve the movement of the position coordinate of the captured image data. Here, dx2, dy2 is a coordinate value with the origin at the center of the lens after the enlargement/reduction correction is performed. Here, a destination of the position coordinate of the center of the lens before the movement is (cx, cy). 
     
       
         
           
             
               
                 
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                   7 
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     The composition portion  524  performs a cutout relative to the captured image data after the movement control is performed by the movement control portion  523  so as to conform to the display region of the display device  8  and thereafter combines display information for assisting the steering of the driver. 
       FIG. 9  is a diagram illustrating an example of the image data after the composition is performed by the composition portion  524 . In the example illustrated in  FIG. 9 , conditions around the left front wheel of the vehicle  1  captured by the imaging portion  16   b  is displayed at a display region (a captured image data  901 ). In addition, conditions around the right front wheel of the vehicle  1  captured by the imaging portion  16   d  is displayed at a display region (a captured image data  902 ). Further, information by which the pitch angle and the roll angle of the vehicle  1  are recognizable is displayed at a display region  903 . That is, an inclination of an icon  921  representing the vehicle  1  indicates the roll angle while a distance between a center line  912  passing through the icon  921  and a line  911  indicates the pitch angle. Accordingly, in the embodiment, information by which the roll angle and the pitch angle are recognizable is indicated, however, display method is not limited to the above and other display method is acceptable. 
     Meanwhile, the captured image data after the cutout by the composition portion  524  is displayed at a display region (a captured image data  904 ). In other words, the rotation correction is performed so that a lower direction of the captured image data corresponds to the direction of gravity. Accordingly, the driver may easily and objectively recognize the conditions of the surroundings of the vehicle  1 . 
     However, in a case where the driver tries to recognize the conditions of the surroundings of the vehicle  1  with the captured image data displayed at the display device  8 , it may be difficult to recognize the inclination of the vehicle  1  from the captured image data depending on the conditions of the surroundings of the vehicle  1 . In addition, because a tiltmeter  906  indicating the pitch angle and the roll angle of the vehicle  1  is shown at the display device  8 , the driver is desired to gaze the tiltmeter  906 , or to watch the tiltmeter  906  carefully in order to recognize the pitch angle and the roll angle. In a case where the driver gazes the captured image data, it may be difficult for the driver to recognize what is displayed at the tiltmeter  906 . 
     Here, according to the embodiment, respective background colors of the display regions  903 ,  908  change in response to the inclination angle (the pitch angle or the roll angle) of the vehicle  1 . Accordingly, the driver may recognize the current inclination angle of the vehicle  1  without gazing the tiltmeter  906 . In a case where the driver desires to know the inclination angle further accurately when recognizing the current inclination angle of the vehicle, the tiltmeter  906  is to be watched. Thus, the driver may easily recognize the conditions of the surroundings of the vehicle  1 . 
     Then, the output portion  505  outputs the image data that is composited by the composition portion  524  to the display device  8 . Accordingly, together with the aforementioned captured image data after the correction processing is performed, information by which the roll angle and the pitch angle are recognizable is displayed at the display device  8 . 
     In the example of  FIG. 8 or 9 , an estimated course line  905  of each of the front wheels  3 F is included. The surroundings monitoring ECU  14  (CPU  14   a ) calculates a planned course based on detection results of the steering angle sensor  19  and the tire angle sensor  13   b , for example, and to include (overlap) the estimated course line  905  conforming to the planned course in the output image. The estimated course line  905  is an example of a display element indicating the course that is planned. The surroundings monitoring ECU  14  corrects the display position, size, posture (inclination) and the like of the estimated course line  905  depending on the aforementioned rotation, enlargement/reduction and movement corrections. In addition, in a case where the position of the estimated course line  905  is greatly deviated from a center of the screen, the surroundings monitoring ECU  14  corrects the display region and the estimated course line  905  in a direction where the deviation is reduced. 
     In the example of  FIG. 9 , the inclination of the icon  921  relative to a lateral-direction side of the display region  903  or the display region (the captured image data  904 ) (an upper side or a lower side in  FIG. 9 ) corresponds to the roll angle of the vehicle  1 . Thus, the surroundings monitoring ECU  14  may constitute the tiltmeter  906  (roll angle display portion) using the icon  921  by including an angle scale  906   a  (tilt scale) surrounding the icon  921  in the output image in a manner that an angle of the angle scale  906   a  remains unchanged relative to the display region  903 . For example, only by the display of the display region (the captured image data  904 ), it may be difficult to understand the lateral direction, the vertical direction, and the posture (the roll angle or the pitch angle) of the vehicle  1 . In this point, as in the example of  FIG. 9 , the icon  921  that performs rotation (rolling) and pitching is displayed and the tiltmeter  906  is displayed on the screen depending on the roll angle and the pitch angle so that the lateral direction, the vertical direction and the posture (the roll angle) of the vehicle  1  may be easily understood, regardless of the state of the image of the display region (the captured image data  904 ). Accordingly, the display region (the captured image data  904 ) and the display region (the captured image data  903 ) are displayed together (displayed within the same screen or displayed in parallel with each other) so that the state around the vehicle and the state of the posture of the vehicle may be further easily understood. 
     In addition, the embodiment may not perform the aforementioned rotation, enlargement/reduction and movement corrections on a constant basis and may be specified to perform the aforementioned corrections in a case where the vehicle  1  is brought to the off-road mode. For example, the image processing portion  504  performs the aforementioned rotation, enlargement/reduction and movement corrections at the time of the off-road mode by referring to information acquired by the acquisition portion  501  indicating whether or not the vehicle  1  is in the off-road mode. 
     Here, the off-road mode corresponds to the mode for bringing out a four-wheel driving performance of the vehicle  1  during the off-road driving and the mode for specifying a total transfer gear to be low. That is, in the embodiment, the captured image data displayed at the display device  8  is switched in association with the operation when the off-road driving is performed. At this time, in the embodiment, the switching of the image displayed at the display device  8  is not limited to be performed in a case where the vehicle  1  is switched to the off-road mode. For example, in a case where the vehicle  1  is switched to the four-wheel driving in a two/four wheel drive switching, it may be controlled that the image after the rotation correction is performed is displayed. 
     According to the embodiment, the tiltmeter  906  is not limited to be displayed on a constant basis in the off road mode, and the tiltmeter  906  may be displayed in a case where the inclination angle of the vehicle  1  comes to be equal to or greater than a predetermined angle. According to the embodiment, in a case where the inclination angle of the vehicle  1  is less than, for example, 10 degrees (i.e., serving as a first angle), the output portion  505  outputs an output image data including the captured image data. In a case where the inclination angle of the vehicle  1  comes to be equal to or greater than, for example, 10 degrees, the output portion  505  outputs an output image data in which the captured image data and the tiltmeter  906  are combined. Moreover, in a case where the inclination angle of the vehicle  1  comes to be equal to or greater than, for example, 30 degrees (i.e., serving as a second angle), the composition portion  524  combines the captured image data and the tiltmeter  906  and the output portion  505  changes the display method of the output image data. 
     Next, a display processing at the display device  8  in the surroundings monitoring portion  500  according to the embodiment is explained.  FIG. 10  is a flowchart illustrating procedures of the aforementioned processing in the surroundings monitoring portion  500  according to the embodiment. 
     First, the acquisition portion  501  acquires the captured image data from the imaging portions  16  (step S 1001 ). Next, the acquisition portion  501  acquires the acceleration data from the acceleration sensors  26  (step S 1002 ). 
     Then, the angle calculation portion  502  calculates the roll angle and the pitch angle of the vehicle  1  from the acceleration data (step S 1003 ). 
     Next, the filtering control portion  503  performs filtering by low-pass filter relative to the calculated roll angle and the calculated pitch angle (step S 1004 ). 
     Then, the rotation control portion  521  performs the rotation control relative to the captured image data depending on the roll angle (step S 1005 ). 
     Next, the reduction/enlargement control portion  522  and the movement control portion  523  perform the enlargement control and the movement control on the captured image data after the rotation control is performed (step S 1006 ). 
     Then, the composition portion  524  performs the cutout conforming to the display region displayed at the display device  8  relative to the captured image data after the enlargement control and the movement control are performed (step S 1007 ). 
     Next, the composition portion  524  combines the captured image data indicating the state around the front wheels and the display information by which the pitch angle and the roll angle are recognizable relative to the captured image data that is cut out (step S 1008 ). 
     Then, the output portion  505  outputs the image data after the composition by the composition portion  524  to the display device  8  (step S 1009 ). 
     Next, the composition processing of the image data by the surroundings monitoring portion  500  of the embodiment for being displayed at the display device  8  will be explained. The composition processing is at step S 1008 .  FIG. 11  is a flowchart illustrating the aforementioned processing procedures proceeded by the surroundings monitoring portion  500  of the embodiment. 
     First, the composition portion  524  determines whether the inclination angle (the pitch angle or the roll angle) input from the filtering control portion  503  is equal to or greater than 10 degrees (step S 1101 ). In a case where the composition portion  524  determines that the inclination angle is less than 10 degrees (No in step S 1101 ), the composition portion  524  combines the captured image data captured by the imaging portions  16   a ,  16   b ,  16   c  and generates an output image data (step S 1102 ). 
       FIG. 12  is a view illustrating an example of the output image data generated by the composition portion  524  in step S 1102 . As shown in  FIG. 12 , a captured image data  1201  captured by the imaging portion  16   a , a captured image data  1203  captured by the imaging portion  16   b , and a captured image data  1202  captured by the imaging portion  16   d  are combined. For example, the tiltmeter  906  is not displayed at a display region  1204 . In  FIG. 12 , because the driver only has to refer to the captured image data, the burden for the driver may be reduced. 
     On the other hand, in a case where the composition portion  524  determines that the inclination angle (the roll angle or the pitch angle) input from the filtering control portion  503  is equal to or greater than 10 degrees (Yes in step S 1101 ), the composition portion  524  determines whether the inclination angle (the roll angle or the pitch angle) is equal to or greater than 30 degrees (step S 1103 ). In a case where the composition portion  524  determines that the inclination angle is less than 30 degrees (No in step  1103 ), the composition portion  524  generates an output image data by combining the captured image data and the tiltmeter  906  (step S 1104 ). 
       FIG. 13  is a view illustrating the output image data generated by the composition portion  524  in step S 1104 . As shown in  FIG. 13 , a captured image data  1301  captured by the imaging portion  16   a , a captured image data  1303  captured by the imaging portion  16   b , a captured image data  1302  captured by the imaging portion  16   d  and a tiltmeter  1306  are combined. Display regions  1304 ,  1305  of the output image data shown in  FIG. 13  are displayed with a background color specified for the inclination angles, 10 to 30 degrees, of the vehicle  1 . Any background color, for example, blue, is applicable. 
     On the other hand, in a case where the composition portion  524  determines that the inclination angle (the roll angle or the pitch angle) input from the filtering control portion  503  comes to be greater than 30 degrees (Yes in step S 1103 ), the composition portion combines the captured image data and the tiltmeter  1306  generates an output image data in which the color of the background is changed to a color for warning (step S 1105 ). 
       FIG. 9  illustrates the output image data generated in a case where the inclination angle (the roll angle or the pitch angle) comes to be equal to or greater than 30 degrees. As mentioned above, the composition portion  524  combines the captured image data  901 ,  902 ,  904  and the tiltmeter  906  and the output portion  505  changes the background colors of display regions  907 ,  908  to the color for warning. The color for warning is, for example, red or yellow. 
     According to the embodiment, a brightness value, a color tone and a coloration of the display region displayed at the display device  8  may change in accordance with the inclination angle of the vehicle  1 . 
     As such, because the background color is changed to the color for warning, the driver may recognize the inclination state of the vehicle  1  without gazing the tiltmeter  906 , or without watching the tiltmeter  906  carefully. That is, the driver may recognize the inclination state of the vehicle  1  from the background color of the display device  8  while recognizing the conditions of the surroundings by gazing, or carefully watching the captured image data displayed at the display device  8 . That is, it is difficult for the driver to recognize the current state of the vehicle  1  by referring to only the captured image data displayed at the display device  8 . However, according to the embodiment, because the state of the inclination angle of the vehicle  1  is displayed with the background color when the display device  8  displays the captured image data, the driver may recognize various statuses of the vehicle  1  by only referring to the display device  8 . Accordingly, the burden for the driver when steering may be reduced. 
     As mentioned above, the composition portion  524  of the embodiment composes the output image data that changes the background color in accordance with the conditions of the inclination of the vehicle  1 . Thus, the output portion  505  outputs the output image data that changes the background color in accordance with the inclination angle of the vehicle  1 . 
     A first modified example of the embodiment will hereunder be explained. According to the embodiment, the background color changes, or varies as the display method. However, the display method that changes in accordance with the inclination angle is not limited to the background color. According to the first modified example of the embodiment, the warning sign is displayed as the display method in a case where the inclination angle of the vehicle  1  comes to be equal to or greater than 30 degrees. 
       FIG. 14  is a view illustrating an example of an image data generated by the composition portion  524  in a case where the inclination angle of the vehicle comes to be equal to or greater than 30 degrees. The image data shown in  FIG. 14  illustrates a warning sign  1401  (i.e., serving as an icon) in addition to the combination of the captured image data  901 ,  902 ,  904  and the tiltmeter  906 . In a case where the inclination angle of the vehicle  1  comes to be equal to or greater than 30 degrees, the warning sign  1401  is applied to the image data outputted by the composition portion  524 . 
     According to the first modified example of the embodiment, because the warning sign  1401  is displayed at the display device  8  in addition to the captured image data  901 ,  902 ,  904  and the tiltmeter  906  in a case where the driver refers to the display device  8 , the driver may recognize the conditions of the vehicle  1 . 
     A second modified example of the embodiment will hereunder be explained. According to the embodiment, the background of the display region excluding the captured image data and the tiltmeter  906  changes, or varies in a case where the inclination angle of the vehicle  1  comes to be equal to or greater than 30 degrees. According to the first modified example of the embodiment, the warning sign is displayed at the display region in a case where the inclination angle of the vehicle  1  comes to be equal to or greater than 30 degrees. Alternatively, the display method of the captured image data and of the tiltmeter  906  can be changed. According to the second modified example of the embodiment, the display method of the captured image data captured by the imaging portions  16   b ,  16   d  is changed. 
       FIG. 15  is a view illustrating an example of an image data being generated in a case where the tilt angle of the vehicle  1  comes to be equal to or greater than 30 degrees. Captured image data  904 ,  1501 ,  1502  and the tiltmeter  906  are combined to generate the image data shown in  FIG. 15 . Comparing to a case where the inclination angle is less than 30 degrees, the display method of the captured image data  1501 ,  1502  is changed. As shown in  FIG. 15 , the brightness value of the captured image data  1501 ,  1502  changes in accordance with the height relative to the lateral plane. That is, the darker the portions of the captured image data  1501 ,  1502  are, the lower the height relative to the lateral plane is. The brighter the portions of the captured image data  1501 ,  1502  are, the higher the height relative to the lateral plane is. As shown in  FIG. 15 , the left of the vehicle is positioned at a lower position and the right of the vehicle is positioned at a higher position. Because the display shown in  FIG. 15  is displayed in a case where the inclination angle of the vehicle  1  comes to be equal to or greater than 30 degrees, the driver may recognize the inclination state of the vehicle  1 . 
     According to the second modified example of the embodiment, the output portion  505  outputs the image data that changes the display method (for example, the color tone or the brightness value) of the captured image data captured by the imaging portions  16   b ,  16   d  in a case where the inclination angle comes to be equal to or greater than 30 degrees. Alternatively, the captured image data that changes the display method is not limited to the captured image data captured by the imaging portions  16   b ,  16   d . Alternatively, the display method (for example, the color tone or the brightness value) of the captured image data captured by the imaging portion  16   a  can be changed. 
     A third modified example of the embodiment will hereunder be explained. According to the aforementioned embodiment and the first and second modified examples of the embodiment, the display method is changed in a case where the inclination angle of the vehicle  1  comes to be equal to or greater than 30 degrees. However, according to the aforementioned embodiment and the first and second modified examples of the embodiment, the inclination angle is not specified as the pitch angle or the roll angle. Here, according to the third modified example of the embodiment, the composition portion  524  changes the display method of the display region of the output image data in accordance with the roll angle, and the composition portion  524  changes the display method of the display region of the output image data in accordance with the pitch angle. For example, in a case where the roll angle comes to be equal to or greater than 30 degrees, the color of a predetermined display region of the output image data can be changed red, and in a case where the pitch angle comes to be equal to or greater than 30 degrees, the color of the predetermined display region of the output image data can be changed yellow (i.e., serving as a first display method). In a case where the roll angle comes to be equal to or greater than 30 degrees and the pitch angle is equal to or greater than 30 degrees, a color of the predetermined display region can be changed orange (i.e., serving as a second display method). Thus, the driver may recognize the inclination state of the vehicle  1  without gazing the tiltmeter  906 , or without watching the tiltmeter  906  carefully. 
     According to the aforementioned embodiment and the first, second and third modified examples of the embodiment, in a case where the display device  8  displays the captured image data and the tiltmeter  906 , the display method changes in accordance with the inclination angle of the vehicle  1 . Accordingly, the driver may recognize the inclination state of the vehicle  1  by watching the captured image data without referring to the tiltmeter  906 . Thus, the driver may easily recognize the conditions of the surroundings of the vehicle  1 . That is, because the driver may easily recognize the conditions of the surroundings of the vehicle  1 , the burden for the driver when steering may be reduced. 
     According to the aforementioned embodiment, the vehicle control apparatus includes the first acquisition portion (the acquisition portion  501 ) acquiring the captured image data ( 901 ,  902 ,  904 ,  1201 ,  1202 ,  1203 ,  1301 ,  1302 ,  1303 ,  1501 ,  1502 ) outputted from the imaging portion ( 16 ,  16   a ,  16   b ,  16   c ,  16   d ) that is provided at the vehicle ( 1 ) and that images the surrounding of the vehicle ( 1 ), the second acquisition portion (the angle calculation portion  502 ) acquiring the inclination angle of the vehicle ( 1 ) on a basis of the state information of the vehicle ( 1 ), the state information outputted from the vehicle state detection portion ( 26 ) that is provided at the vehicle ( 1 ), and the output portion ( 505 ) being configured to output the output image data to the display device ( 8 ), the output image data including the captured image data ( 901 ,  902 ,  904 ,  1201 ,  1202 ,  1203 ,  1301 ,  1302 ,  1303 ,  1501 ,  1502 ) and the inclination angle display information indicating the inclination angle of the vehicle ( 1 ), the output portion ( 505 ) changing the display method within the output image data in accordance with the inclination angle of the vehicle ( 1 ) and outputting the output image data. 
     Accordingly, as an example, because the driver recognizes the conditions of the surroundings and the inclination of the vehicle  1  when referring to the display device  8 , the driver may easily recognize the conditions of the surroundings of the vehicle. 
     According to the aforementioned embodiment, the output portion ( 505 ) changes the color in accordance with the inclination angle of the vehicle ( 1 ) as the display method within the output image data. 
     Accordingly, as an example, because the driver may recognize the inclination of the vehicle  1  with color, the burden for the driver when steering can be reduced. 
     According to the aforementioned embodiment, the output portion ( 505 ) outputs the output image data including the captured image data ( 901 ,  902 ,  904 ,  1201 ,  1202 ,  1203 ,  1301 ,  1302 ,  1303 ,  1501 ,  1502 ) that is rotationally controlled on a basis of the inclination angle of the vehicle ( 1 ) relative to the lateral direction or the horizontal direction, the lateral direction that is the direction included in the lateral plane orthogonal to the direction of gravity, by using the inclination angle data of the vehicle ( 1 ), the inclination angle data acquired by the second acquiring portion (the angle calculation portion  502 ). 
     Accordingly, as an example, because the driver may recognize the conditions of the surroundings of the vehicle  1  with the captured image data, the burden for the driver when steering can be reduced. 
     According to the aforementioned embodiment, the output portion ( 505 ) outputs the output image data including the captured image data ( 901 ,  902 ,  904 ,  1201 ,  1202 ,  1203 ,  1301 ,  1302 ,  1303 ,  1501 ,  1502 ) in a case where the inclination angle of the vehicle ( 1 ) is less than the predetermined first angle. The output portion ( 505 ) outputs the output image data including the captured image data ( 901 ,  902 ,  904 ,  1201 ,  1202 ,  1203 ,  1301 ,  1302 ,  1303 ,  1501 ,  1502 ) and the inclination angle display information in a case where the inclination angle of the vehicle ( 1 ) is equal to or greater than the first angle. The output portion ( 505 ) outputs the output image data including the captured image data ( 901 ,  902 ,  904 ,  1201 ,  1202 ,  1203 ,  1301 ,  1302 ,  1303 ,  1501 ,  1502 ) and the inclination angle display information and changes the display method within the display region ( 903 ,  907 ,  908 ,  1204 ,  1304 ,  1305 ) of the output image data in a case where the inclination angle of the vehicle ( 1 ) is equal to or greater than the predetermined second angle that is greater than the first angle. 
     Accordingly, as an example, because the driver may recognize the inclination of the vehicle  1  with the display method displayed at the display device  8  without referring to the inclination angle display information, the driver may easily recognize the conditions of the surroundings of the vehicle  1 . 
     According to the aforementioned embodiment, the inclination angle includes the first inclination angle of the vehicle ( 1 ), the first inclination angle serving as the roll angle, and the second inclination angle of the vehicle ( 1 ), the second inclination angle serving as the pitch angle. The display method includes the first display method and the second display method. The output portion ( 505 ) changes the first display method within the display region ( 903 ,  907 ,  908 ,  1204 ,  1304 ,  1305 ) of the output image data in accordance with the roll angle. The output portion ( 505 ) changes the second display method within the display region ( 903 ,  907 ,  908 ,  1204 ,  1304 ,  1305 ) of the output image data in accordance with the pitch angle. 
     Accordingly, because the display method changes in accordance with the inclination angle of the roll angle or of the pitch angle, the driver may recognize the inclination state of the vehicle  1  without gazing the tiltmeter  906 , or without watching the tiltmeter  906  carefully. 
     According to the aforementioned embodiment, the output portion ( 505 ) changes at least one of the color of the captured image data ( 901 ,  902 ,  904 ,  1201 ,  1202 ,  1203 ,  1301 ,  1302 ,  1303 ,  1501 ,  1502 ), the color of the display region ( 903 ,  907 ,  908 ,  1304 ,  1305 ) excluding the captured image data ( 901 ,  902 ,  904 ,  1201 ,  1202 ,  1203 ,  1301 ,  1302 ,  1303 ,  1501 ,  1502 ) and the inclination angle display information, and the color within the inclination angle display information as the display method. 
     Accordingly, the driver may recognize the conditions of the vehicle  1 . 
     According to the aforementioned embodiment, the display device ( 8 ) displays the output image data outputted from the output portion ( 505 ), the display device ( 8 ) displaying the icon (the warning sign  1401 ) warning the driver with the output image data as the display method. 
     Accordingly, because the icon for warning is displayed with the output image data, the driver may recognize the conditions of the vehicle  1 . 
     According to the aforementioned embodiment, the display device ( 8 ) displays the output image data outputted from the output portion ( 505 ), the display device ( 8 ) displaying the output image data that changes the color at the region within the captured image data ( 1501 ,  1502 ) in accordance with the difference in height relative to the lateral plane as the display method. 
     Accordingly, for example, the driver may recognize the inclination state of the vehicle  1  in a case where the display shows in a manner that the darker the portion of the captured image data is, the lower the height relative to the lateral plane is, and the brighter the portion of the captured image data is, the higher the height relative to the lateral plane is. 
     The principles, preferred embodiment and mode of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims, be embraced thereby.