JP2009147906A - Vehicle periphery monitoring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle periphery monitoring device capable of appropriately performing exposure control of an imaging means when switching a use of the imaging means. <P>SOLUTION: The vehicle periphery monitoring device is installed on a vehicle, performs photometry regarding the inside of a photometric area which is set with respect to an imaging range of an on-vehicle camera that images an image of the periphery of the vehicle, and performs exposure control of the on-vehicle camera based on a result of the photometry, wherein, with respect to the imaging range, a plurality of areas A, B and C different from one another are designated. By changing over a display switch for turning on and off a monitor, any one of the areas A, B and C is set as the photometric area. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle periphery monitoring apparatus that captures an image of the periphery of a vehicle with a camera installed in the vehicle and displays the captured image on a display device installed in the vehicle.

  In recent years, there are automobiles that provide driving assistance using in-vehicle cameras. For example, when the front of the vehicle is imaged with an in-vehicle camera, the vehicle is automatically driven along the white line on the road recognized from the imaging result, or when the vehicle is stopped or traveling at a low speed, the in-vehicle camera is imaged and the imaging result is captured in the vehicle An automobile or the like that allows a driver to grasp the situation around the vehicle by displaying on the monitor is known. When using a vehicle-mounted camera, it is necessary to accurately control the exposure of the vehicle-mounted camera according to the situation around the vehicle in order to make the imaging result of the vehicle-mounted camera clearer.

Patent Document 1 describes an image recognition device that accurately controls the exposure of an in-vehicle camera in accordance with an imaging environment such as daytime or nighttime. In Patent Literature 1, the exposure control of the rear imaging device that images the rear of the vehicle is performed based on the imaging result of the front imaging device that images the front of the vehicle. For example, the front imaging device detects an illuminance value from the result of imaging a certain imaging target. Then, after the vehicle passes through the imaging target, when the rear imaging device images the same imaging target, the exposure control of the rear imaging device is performed based on the illuminance value detected during imaging by the front imaging device. I do. As a result, it is possible to respond quickly to changes in ambient brightness during traveling in a tunnel or at night, and the exposure control of the rear imaging device can be appropriately performed. And the imaging result by the rear imaging device can be made clear, and the driver can accurately grasp the rear of the vehicle by displaying the imaging result on the monitor in the vehicle.
JP 2004-32528 A

  By the way, generally, the use of the in-vehicle camera is determined in advance. For this reason, for example, in the case where the left and right oblique forward directions of the vehicle are monitored at an intersection and when the obstacles immediately before the vehicle are monitored, even in the case of capturing images in substantially the same direction, the on-vehicle camera for each application Is prepared. Therefore, it is desired to use one in-vehicle camera for a plurality of uses from the viewpoint of cost reduction and increase in the number of parts.

  However, in such a case, since the imaging target is different for each application, there is a problem that exposure control according to the imaging target must be appropriately performed when switching the usage of the in-vehicle camera. And in patent document 1 which performs exposure control from the result imaged with a time difference, such a problem cannot be solved.

  The present invention has been made in view of such circumstances, and an object of the present invention is to designate two or more different areas within the imaging range of the imaging means, and to specify one of the designated areas at a predetermined timing. Is set as a photometric area, and the exposure control of the image pickup means is controlled based on the result of the photometry performed in the photometry area, so that the exposure control of the image pickup means is appropriately performed when the use of the image pickup means is switched. An object of the present invention is to provide a vehicle periphery monitoring device.

  Another object of the present invention is to provide a first area corresponding to a predetermined distance forward from the front of the vehicle downward in the imaging range of the imaging means capable of imaging the front of the vehicle, and from the front to the left and right of the vehicle. Correspondingly, by providing a second area different from the first area, it is possible to provide a vehicle periphery monitoring device capable of obtaining clear captured images immediately before the vehicle and in other two directions with a single imaging means. There is to do.

  Another object of the present invention is a configuration in which when an object in front of the vehicle is detected, the display means for displaying the captured image is forced to be switched from OFF to when the object appears in front of the vehicle. Another object of the present invention is to provide a vehicle periphery monitoring device that displays a captured image in front of the vehicle on the display means and warns the driver.

  Another object of the present invention is to take a difference between picked-up images taken with a time difference by the image pickup means and perform object detection based on the result of the difference, so that the vehicle can be used only when the object is reflected on the image pickup means. An object of the present invention is to provide a vehicle periphery monitoring device that displays a forward captured image on a display means.

  The vehicle periphery monitoring device according to the present invention is installed in a vehicle, and includes an imaging unit that images the periphery of the vehicle, a photometric unit that performs photometry in a photometric area set within an imaging range of the imaging unit, and the photometric unit In the vehicle periphery monitoring device comprising an exposure control means for performing exposure control of the imaging means based on the photometric result by the designation means for designating a plurality of different areas within the imaging range, and at a predetermined timing, And a setting means for setting one of the areas designated by the designation means as the photometric area.

  In the present invention, a plurality of different areas are designated within the imaging range of the imaging means, and one of the designated areas is set as a photometric area at a predetermined timing. Then, the exposure control of the imaging means is performed based on the result of the photometry performed within the set area. In other words, a plurality of areas to be set as the photometric areas to be measured when performing exposure control of the imaging means are designated within the imaging range. Thereby, even when one imaging unit is used for a plurality of uses, it is possible to set a region corresponding to each use from a plurality of designated regions as a photometric region.

  In the vehicle periphery monitoring device according to the present invention, the imaging means is installed in the vehicle so that imaging in front of the vehicle is possible, and the designation means corresponds to a predetermined distance forward from the front of the vehicle downward. One region and a second region corresponding to the left and right front from the front of the vehicle and different from the first region are designated in the imaging range.

  In the present invention, the imaging means is capable of imaging the front of the vehicle, corresponds to a first area corresponding to a predetermined distance forward from the front of the vehicle, and corresponds to the left and right front from the front of the vehicle. A second area different from the first area is designated within the imaging range as an area to be set as a photometric area. As a result, it becomes possible to clearly image one of the two areas at a predetermined timing by one imaging means.

  A vehicle periphery monitoring device according to the present invention is installed so that a driver can visually recognize, a display unit that displays a captured image captured by the imaging unit, a switch that turns on and off the display unit, and the first region An object detection means for detecting an object, wherein the setting means sets the second area as the photometric area when the switch is on, and sets the first area when the switch is off. The photometric region is configured to be set, and further includes switch control means for forcibly turning on the switch when the object detection means detects an object when the switch is off.

  In the present invention, when the switch for turning on / off the display unit that displays the captured image captured by the imaging unit is turned on, the photometric region is set to the second region. That is, by turning on the display means, the driver can confirm a clear captured image in areas other than the first region of the vehicle on the display means. In addition, when the switch is off, the photometry area is set to the first area corresponding to the position immediately before the vehicle, and when an object in the first area is detected, the switch is forcibly turned on. Thereby, the driver | operator can confirm the captured image of a 1st area | region with a display means, when the object just before a vehicle is detected.

  In the vehicle periphery monitoring device according to the present invention, the imaging means is installed in the vehicle so that imaging in front of the vehicle is possible, and the designation means includes a paint display provided on the road surface of the road in front of the vehicle. The paint display area is designated within the imaging range.

  In the present invention, the imaging means is capable of imaging in front of the vehicle, and by designating an area including a paint display provided on the road surface of the road within the imaging range, such as “stop” displayed on the road The road information can be clearly imaged.

  A vehicle periphery monitoring device according to the present invention is installed so that a driver can visually recognize, a display unit that displays a captured image captured by the imaging unit, a switch that turns on and off the display unit, and a paint display region. Paint display detection means for detecting paint display, the setting means is configured to set the paint display area as the photometry area when the switch is off, and when the switch is off, It further comprises switch control means for forcibly turning on the switch when the paint display detection detects a paint display.

  In the present invention, by detecting the paint display provided on the road surface of the road, for example, when a paint display that issues a warning in front of an intersection or a curve is detected, the switch of the display means may be forcibly turned on. it can. As a result, the first area that becomes the blind spot of the driver can be confirmed by the display means, and an accident can be avoided in some cases.

  The vehicle periphery monitoring device according to the present invention further includes specifying means for specifying the position of the shadow of the own vehicle, and the setting means sets the specifying means when the photometric area is set to the first area or the paint display area. The photometric area is set to a part or all of the first area or the paint display area according to the position of the shadow specified by.

  In the present invention, by setting the photometric area based on the shadow of the own vehicle, it is possible to prevent the shadow from overlapping the photometric area and to set the photometric area so that the shadow overlaps the entire photometric area. Thereby, the brightness of a photometry area | region can be made substantially equal.

  The vehicle periphery monitoring apparatus according to the present invention is characterized in that the object detection means is configured to take a difference between captured images taken with a time difference by the imaging means and perform object detection based on a result of the difference. To do.

  In the present invention, object detection is performed based on a difference result between captured images captured by the imaging unit with a time difference. In other words, the object is detected when the object is reflected on the imaging means.

  According to the present invention, the imaging means can be used for a plurality of applications by designating a plurality of areas to be set as the photometric area within the imaging range. Then, when switching the usage of the imaging unit, the exposure control of the imaging unit can be appropriately performed by setting any one of the designated areas as the photometric area.

  According to the present invention, it is not necessary to install an imaging unit in each direction or area in the vehicle, and it is possible to prevent an increase in the number of components.

  According to the present invention, when an object such as a person or a vehicle jumping forward in the vehicle is detected, a captured image can be displayed on the display unit even when the switch is off. This can warn the driver that there is an obstacle in the immediately preceding area.

  According to the present invention, the captured image of the immediately preceding region can be displayed on the display unit only when the object is reflected on the imaging unit. Further, it is not necessary to separately provide a sensor for detecting an object, and an increase in the number of parts can be suppressed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
A first embodiment of the present invention will be described. FIG. 1 is a block diagram schematically illustrating functions of the vehicle periphery monitoring device according to the present embodiment.

The vehicle periphery monitoring device according to the present embodiment is a camera ECU (Electronic Control Unit).
10, an in-vehicle camera 20 and a monitor 30 are provided. The camera ECU 10 is connected to the in-vehicle camera 20 and the monitor 30 with a signal cable. In the present embodiment, the camera ECU 10 and the monitor 30 are configured independently. However, the camera ECU 10 and the monitor 30 may be integrated. The monitor 30 is installed in the vehicle so as to be visible to the driver.

  As will be described in detail later, the in-vehicle camera 20 is installed at the front portion of a vehicle including a vehicle periphery monitoring device. And the vehicle-mounted camera 20 can image the range including the left-right side of the front part of a vehicle, and the front direction of a vehicle (refer FIG. 2 mentioned later). The in-vehicle camera 20 includes a plurality of image sensors 21, a photometric calculation unit 22, a signal processing unit 23, an exposure / gain control unit 24, and an output I / F 25.

  When the image sensor 21 senses light through a lens, an electric charge is generated according to the intensity of the light, and the generated electric charge is accumulated. The image sensor 21 sequentially reads the accumulated charges and outputs them as electrical signals to the signal processing unit 23 via the photometric calculation unit 22.

  The photometry calculation unit 22 performs photometry in the photometry area set for the imaging range of the in-vehicle camera 20. Specifically, the photometry calculation unit 22 measures the amount of light taken into the photometry area based on the charge capacity accumulated in the image sensor 21 corresponding to the photometry area. The measurement result obtained by the photometry calculation unit 22 is output to the exposure / gain control unit 24.

  The signal processing unit 23 A / D converts the electrical signal output from the in-vehicle camera 20 into digital data, and outputs the converted data to the camera ECU 10 from the output I / F 25.

  The exposure / gain control unit 24 controls the exposure of the in-vehicle camera 20 based on the photometry result obtained by the photometry calculation unit 22. Here, the exposure control refers to controlling the time for accumulating the generated charges in the image sensor 21 by controlling the operation speed of a so-called electronic shutter. Specifically, the image sensor 21 accumulates electric charges when a voltage is applied. That is, by controlling the time during which the voltage is applied to the image sensor 21, the time for accumulating the charge in the image sensor 21 can be controlled.

  For example, when the amount of light in the photometry area is small from the photometry result obtained by the photometry calculation unit 22, the time for accumulating charges in the image sensor 21 corresponding to the photometry area is lengthened. As a result, the charge capacity accumulated in the image sensor corresponding to the photometric area increases, and a stronger electric signal is output from the in-vehicle camera 20. As a result, in the image processing unit 11 of the camera ECU 10 to be described later, it is possible to acquire digital data in which a portion corresponding to the photometric area becomes clearer.

  The camera ECU 10 includes an image processing unit 11, a parameter control unit (setting unit) 12, a memory 13, a display control unit 14, an input I / F 15, and an external I / F 16. 30 is operated.

  The input I / F 15 is connected to the output I / F 25 of the in-vehicle camera 20 and outputs a signal input from the in-vehicle camera 20 to the image processing unit 11.

  The image processing unit 11 performs predetermined pixel interpolation processing and color conversion processing on the digital data A / D converted by the signal processing unit 23 of the in-vehicle camera 20 and stores the data in the memory 13. In addition, the image processing unit 11 compares two captured images captured by the in-vehicle camera 20 with a minute time difference. Specifically, the image processing unit 11 performs edge extraction processing on two captured images to obtain respective edge extracted images, and obtains a difference between the edge extracted images. Then, as a result of the difference, it is detected whether or not an object has appeared within the imaging range of the in-vehicle camera 20.

  The parameter control unit 12 determines various parameters and controls the in-vehicle camera 20 and the display control unit 14. Specifically, the parameter control unit 12 is connected to an external I / F 16. Further, the external I / F 16 includes a display switch 31 for turning on / off the monitor 30, a speed sensor for detecting the speed of the vehicle, a sensor for acquiring the position of a shift lever for changing gears (none of which are shown), and the like. It is connected. The position of the shift lever is the so-called “R” range or “D” range.

  And the parameter control part 12 sets a photometry area | region with respect to the imaging range of the vehicle-mounted camera 20, for example based on the input value from the external I / F16 or the image processing part 11, and sets the set photometric area to the vehicle-mounted camera 20 Output to. In addition, the display control unit 14 is driven, and the captured image stored in the memory 13 is displayed on the monitor 30.

  The display control unit 14 is controlled by the parameter control unit 12 and outputs the captured image and other images stored in the memory 13 to the monitor 30.

  Next, the imaging range of the in-vehicle camera 20 and the photometric area set for the imaging range will be described.

  2 and 3 are schematic diagrams for explaining a photometric area set for the imaging range of the in-vehicle camera 20, and FIG. 2 (a) is a view seen from above the vehicle. b) is a view from the side of the vehicle. FIG. 3 shows an imaging range viewed from the in-vehicle camera 20, and an image similar to the image shown in FIG. 3 is displayed on the monitor 30.

  The in-vehicle camera 20 can simultaneously image the left and right sides of the front portion of the vehicle 1 and the front direction of the vehicle 1. And the photometry area | region of the vehicle-mounted camera 20 is the area 2 (henceforth the front left area 2) equivalent to the diagonal left front direction of the vehicle 1 in the imaging range of the vehicle-mounted camera 20, as shown in FIG.2 and FIG.3. A region A corresponding to a part, a region B corresponding to a part of an area 3 (hereinafter referred to as the right front area 3) corresponding to the diagonally forward right direction of the vehicle 1, and a predetermined distance from the front portion of the vehicle 1 For example, it is set to a region C corresponding to a part of area 4 (hereinafter referred to as immediately preceding area 4) up to 3 m ahead). Note that the area A, the area B, and the area C are set as imaging ranges by the parameter control unit 12. The position of each region may be determined in advance, or the position may be changeable by the driver.

  Note that the front left area 2, the front right area 3, and the front area 4 are different areas in the imaging range. Further, the immediately preceding area 4 is an area from the front part of the vehicle 1 to the front in a predetermined distance shown in FIG. 2B, and is an area obliquely below the horizontal direction. It is an area.

  More specifically, the photometric area is set to any one of area A, area B, and area C. When the photometric areas are set to the areas A and B, exposure control of the in-vehicle camera 20 is performed according to the illuminance of the left front area 2 and the right front area 3. As a result, for example, the left and right diagonal forward directions of the vehicle 1 that are likely to be a driver's blind spot at an intersection or the like are displayed on the monitor 30 with a clearer image.

  When the photometric area is set to the area C, exposure control of the in-vehicle camera 20 according to the illuminance in the immediately preceding area 4 is performed. As a result, immediately before the vehicle 1 that is likely to become a driver's blind spot with a hood or the like is displayed on the monitor 30 with a clearer image. As described above, it is possible to clearly capture images of different areas of the left front area 2, the right front area 3, and the immediately preceding area 4 with one in-vehicle camera 20.

  In the following description, a mode in which the photometric area is set to the area A and the area B is referred to as a left / right monitoring mode, and a mode in which the photometric area is set to the area C is referred to as a previous mode.

  It should be noted that the position, size, range, and the like of the area designated in advance for the imaging range and set as the photometric area can be changed as appropriate. FIG. 5 is a schematic diagram of another example for explaining a photometric area set for the imaging range of the in-vehicle camera 20. In FIG. 3, the area A and the area B are specified independently for the right diagonal forward direction and the left diagonal forward direction of the vehicle 1, but a single area D may be used as shown in FIG. 5. The region D corresponds to the left front area 2, the right front area 3, and the area sandwiched between the left front area 2 and the right front area 3. Further, as shown in FIG. 5, an area E corresponding to the immediately preceding area 4 immediately before the vehicle 1 may be designated within the imaging range as an area E larger than the area C.

  Next, the operation of the vehicle periphery monitoring device configured as described above will be described. FIG. 4 is a flowchart showing the operation of the vehicle periphery monitoring apparatus. The operation shown in FIG. 4 is started when the engine is turned on.

  First, the camera ECU 10 performs initialization (S1). For example, the camera ECU 10 initializes the contents stored in the memory 13, initializes data, and designates the areas A, B, and C for the imaging range of the in-vehicle camera 20.

  Next, the camera ECU 10 determines whether or not the acquired position of the shift lever is in the “R” range (S2). When the position of the shift lever is in the “R” range (S2: YES), that is, when the vehicle 1 travels back, the process proceeds to S17. Then, it is determined whether or not the engine is turned off (S17). When the engine is turned off (S17: YES), this operation ends. On the other hand, when the engine is not turned off (S17: NO), the process returns to S2.

  When the position of the shift lever is not in the “R” range (S2: NO), the camera ECU 10 determines from the acquired speed whether the vehicle 1 is traveling at a low speed (S3). The low-speed traveling is, for example, traveling at a speed of 15 km / h or less, and includes a stopped state. If the vehicle 1 is not traveling at a low speed (S3: NO), the process proceeds to S17.

  When the vehicle 1 is traveling at a low speed (S3: YES), the camera ECU 10 determines whether or not the display switch 31 is on (S4). Therefore, when the vehicle 1 is traveling at a high speed or when traveling backward, the operation of the display switch 31 is invalidated.

  When the display switch 31 is on (S4: YES), the camera ECU 10 executes the left / right monitoring mode (S5), and when it is not on (S4: NO), the camera ECU 10 executes the previous monitoring mode (S10). In other words, in the present embodiment, in order to ensure safety, when the vehicle 1 is in an idling state or when moving forward at a low speed, either the left / right monitoring mode or the immediately preceding monitoring mode can be executed.

  When the left / right monitoring mode is started (S5), the camera ECU 10 sets the photometric areas to the areas A and B shown in FIG. 3 (S6). And the vehicle-mounted camera 20 performs the photometry about the area | region A and the area | region B which were set in the photometry calculation part 22 (S7). Thereafter, the in-vehicle camera 20 performs exposure control by the exposure / gain control unit 24 based on the photometry result by the photometry calculation unit 22 (S8). Thereafter, the camera ECU 10 performs predetermined pixel interpolation processing and color conversion processing in the image processing unit 11 on the signal output from the in-vehicle camera 20 on which exposure control has been performed, stores the signal in the memory 13, and sequentially monitors 30. (S9). As a result, an image in which the left front area 2 and the right front area 3 are clear is displayed on the monitor 30.

  Next, the camera ECU 10 determines whether or not the engine is turned off (S17). When the engine is turned off (S17: YES), this operation ends. If the engine is not off (S17: NO), the process returns to S2.

  On the other hand, if the display switch 31 is not on in S4 (S4: NO), the camera ECU 10 starts the immediately preceding monitoring mode (S10), and sets the photometric area to the area C shown in FIG. 3 (S11). The in-vehicle camera 20 performs photometry for the region C set in the photometry calculation unit 22 (S12). The in-vehicle camera 20 performs exposure control by the exposure / gain control unit 24 (S13).

  Next, the camera ECU 10 performs an object detection process (S14). Specifically, the camera ECU 10 takes the difference as described above with respect to two captured images captured with a time difference in the image processing unit 11. In this case, the image processing unit 11 calculates a difference between the images corresponding to the photometric area set in the area C. The parameter control unit 12 detects an object based on the difference result. Since the area C is set immediately before the vehicle 1 in the immediately preceding area 4 (for example, 3 m ahead), the camera ECU 10 detects that an obstacle such as a person, an animal, or a ball has jumped out immediately before the vehicle 1. it can. By detecting an obstacle by image processing, it is not necessary to provide a sensor for detecting an object in the vehicle 1, and an increase in the number of components can be prevented.

  Subsequently, the camera ECU 10 determines whether an object has been detected (S15). When an object is detected (S15: YES), the monitor 30 is turned on and a captured image is displayed on the monitor 30 (S16). That is, even if the display switch 31 is off, if an obstacle appears in front of the vehicle 1, the camera ECU 10 forcibly displays the captured image immediately before the vehicle even if the display switch 31 is off. Thereby, the driver can confirm an obstacle by displaying an image on the monitor 30 when leaving the vehicle from a vehicle stopped state or during low speed traveling, and can avoid a collision with the obstacle.

  Thereafter, the process proceeds to S17. On the other hand, when the object is not detected (S15: NO), the process proceeds to S17.

  Note that the operation of FIG. 4 is forcibly terminated when the engine is turned off even during the processing.

  As described above, the vehicle periphery monitoring device of the present embodiment can execute the left and right monitoring mode and the immediately preceding monitoring mode, and a plurality of preset photometric areas for performing photometry according to each mode. Set to one of the areas. Thereby, the vehicle periphery monitoring apparatus does not need to prepare the vehicle-mounted camera 20 for each of a plurality of uses, and can appropriately perform the exposure control of the vehicle-mounted camera 20 for each use.

  Further, when an object is detected in front of the vehicle 1, the driver can be warned that there is an obstacle ahead of the vehicle by turning on the monitor 30 that has been turned off and displaying a captured image in front. it can.

  The preferred embodiments of the present invention have been specifically described above, but each configuration, operation, and the like can be changed as appropriate, and are not limited to the above-described embodiments.

  For example, in the above-described embodiment, when a photometric area is set in the area C (area E), an object in the forward direction of the vehicle 1 is detected, but in the area A and area B (area D), the photometric area is detected. May be detected. In this case, for example, it is possible to detect a jump of a person or a vehicle from the left and right direction at an intersection.

  In the above-described embodiment, the object immediately before the vehicle is detected by taking the difference between the captured images captured by the in-vehicle camera 20 with a time difference. However, a sensor for detecting the object may be separately provided. Further, the exposure control may be control for adjusting the amount of light passing through the lens by restricting the lens.

  Furthermore, in the above-described embodiment, the area A, the area B, and the area C are designated as the area corresponding to the left front area 2 and the right front area 3 and the area corresponding to the immediately preceding area 4, and each area is set as a photometric area. However, the photometric area may be set in other areas. For example, you may make it set a photometry area | region to the front which left | separated predetermined distance from the vehicle 1, and the diagonally right and left front of the vehicle 1. FIG.

(Second Embodiment)
Next, a second embodiment according to the present invention will be described. In the first embodiment, the timing for turning on the monitor 30 is set when the obstacle such as a person, an animal, or a ball jumps out immediately before the vehicle 1 (for example, 3 m ahead). The second embodiment is different from the first embodiment in that the paint display on the road surface of the road is detected. The paint display is, for example, characters such as “stop” or “slow down”. Hereinafter, only the difference will be described, the same reference numerals are used for the same members, and the description will be omitted.

  FIG. 6 is a block diagram schematically illustrating functions of the vehicle periphery monitoring device according to the present embodiment. Similar to the first embodiment, the vehicle periphery monitoring device includes a camera ECU 10, an in-vehicle camera 20, and a monitor 30. In addition to the display switch 31, a time acquisition unit 32, a position / direction detection unit 33, and a weather information acquisition unit 34 are connected to the external I / F 16 provided in the camera ECU 10.

  The time acquisition unit 32 receives a radio signal from the outside and acquires information on the current time. The position / direction detection unit 33 acquires information such as the travel position and travel direction of the vehicle 1 from, for example, a car navigation device, and detects the current position of the vehicle 1 and the direction in which the vehicle 1 is facing. The position / direction detection unit 33 may detect the current position of the vehicle 1 and the direction in which the vehicle 1 is facing based on a received GPS (Global Positioning System) signal, a turning angle acquired from a gyro sensor, or the like. The weather information acquisition unit 34 acquires current weather information of the area where the vehicle 1 exists. The weather information acquisition unit 34 may acquire weather information from the state of the vehicle 1 such as determining that it is raining when the wiper is driven.

  The parameter control unit 12 estimates the position of the sun with respect to the vehicle 1 from the direction of the vehicle 1 detected by the position / direction detection unit 33 and the time acquired by the time acquisition unit 32. The parameter control unit 12 specifies a range in which the shadow of the vehicle 1 is generated from the estimated sun position. And the parameter control part 12 specified, when setting a photometry area | region to the area | region corresponded to a part of the immediately preceding area 4 (refer FIG. 2) from the front part of the vehicle 1 to a predetermined distance ahead (for example, 3 m ahead). Based on the shadow range. For example, when the shadow is located in front of the vehicle and the shadow range is larger than a predetermined range, the parameter control unit 12 sets the shadow portion of the vehicle 1 as the photometric area. On the other hand, when the shadow is located in front of the vehicle and the shadow range is smaller than the predetermined range, the parameter control unit 12 sets the photometric area so that the shadow of the vehicle 1 is removed. Thereby, the brightness of the photometric area becomes substantially equal, and the image processing unit 11 can easily detect the paint display from the image corresponding to the photometric area.

  Next, a photometric area set for the imaging range of the in-vehicle camera 20 according to the present embodiment will be described.

  FIG. 7 is a schematic diagram for explaining a photometric area set for the imaging range of the in-vehicle camera when there is no shadow of the vehicle 1, and FIG. 7A shows a case where a part of the road is a photometric area. , (B) shows a case where the entire road is a photometric area. Here, the case where there is no shadow of the vehicle 1 includes a case where the shadow appears on the side or rear of the vehicle but does not appear on the front of the vehicle.

  In the present embodiment, as in the first embodiment, the photometric area of the in-vehicle camera 20 is an area corresponding to a part of the left front area 2 corresponding to the diagonally left front direction of the vehicle 1 in the imaging range of the in-vehicle camera 20. F, set to a region G corresponding to a part of the front right area 3 corresponding to the right front diagonal direction of the vehicle 1 and a region H corresponding to a part of the immediately preceding area 4 from the front part of the vehicle 1 to a predetermined distance ahead. Is done. As shown in FIG. 7, the region H is set at a position where a paint display provided on the road surface can be detected, and may be set at a part of the road (FIG. 7A). (See FIG. 7B).

  FIG. 8 is a schematic diagram for explaining a photometric area set for the imaging range of the in-vehicle camera when there is a shadow of the vehicle 1, where (a) is a small shadow, and (b) is a shadow. The case where is large. As shown in FIG. 8A, when the shadow is located in front of the vehicle and the shadow range is small, the photometric area is set so that the shadow portion of the vehicle 1 does not overlap. On the other hand, as shown in FIG. 8B, when the shadow range is large, a photometric area is set in the shadow of the vehicle 1. At this time, the photometric area may be set according to the shadow of the vehicle 1 within the range of the area H shown in FIG. 7 set in advance, or set only according to the position of the shadow regardless of the area H. May be. In this way, the brightness of the photometric area becomes substantially equal by avoiding the shadow overlapping only a part of the photometric area. Note that the size of the shadow range may be based on, for example, whether one or more characters in the paint display “stop” are included, or may be based on other conditions.

  Next, the operation of the vehicle periphery monitoring device configured as described above will be described. FIG. 9 is a flowchart showing the operation of the vehicle periphery monitoring apparatus.

  The camera ECU 10 performs initialization (S20). Next, the camera ECU 10 determines whether or not the acquired position of the shift lever is in the “R” range (S21). When the position of the shift lever is in the “R” range (S21: YES), the process proceeds to S29. Then, it is determined whether or not the engine is turned off (S29). When the engine is turned off (S29: YES), this operation ends. On the other hand, when the engine is not turned off (S29: NO), the process returns to S21. When the position of the shift lever is not in the “R” range (S21: NO), the camera ECU 10 determines from the acquired speed whether the vehicle 1 is traveling at a low speed (S22). The low-speed traveling is, for example, traveling at a speed of 15 km / h or less, and includes a stopped state. If the vehicle 1 is not traveling at a low speed (S22: NO), the process proceeds to S29.

  When the vehicle 1 is traveling at a low speed (S22: YES), the camera ECU 10 determines whether or not the display switch 31 is on (S23). When the display switch 31 is on (S23: YES), the camera ECU 10 executes the left / right monitoring mode (S24), and when it is not on (S23: NO), the camera ECU 10 executes the immediately preceding monitoring mode (S30). When the left / right monitoring mode is started (S24), the camera ECU 10 sets the photometry area to the area F and the area G (S25). Then, the in-vehicle camera 20 performs photometry for the region F and the region G set in the photometry calculation unit 22 (S26). Thereafter, the in-vehicle camera 20 performs exposure control by the exposure / gain control unit 24 based on the photometry result by the photometry calculation unit 22 (S27). The camera ECU 10 performs predetermined pixel interpolation processing and color conversion processing in the image processing unit 11 on the signal output from the in-vehicle camera 20 for which exposure control has been performed, stores it in the memory 13, and sequentially displays it on the monitor 30. (S28). As a result, an image in which the left front area 2 and the right front area 3 are clear is displayed on the monitor 30.

  Next, the camera ECU 10 determines whether or not the engine is turned off (S29). When the engine is turned off (S29: YES), this operation ends. If the engine is not off (S29: NO), the process returns to S21. On the other hand, when the display switch 31 is not turned on in S23 (S23: NO), the camera ECU 10 starts the immediately preceding monitoring mode (S30), and the parameter control unit 12 executes a photometric area setting process (S31).

  FIG. 10 is a flowchart showing the operation of the photometric area setting process. The parameter control unit 12 acquires the position and orientation of the vehicle 1 detected by the position / direction detection unit 33 (S41). Next, the parameter control unit 12 acquires weather information from the weather information acquisition unit 34 (S42), and acquires information on the current time from the time acquisition unit 32 (S43). The parameter control unit 12 estimates the position of the sun with respect to the vehicle 1 from the position, orientation, and current time of the vehicle 1 (S44). Subsequently, the parameter control unit 12 identifies the shadow of the vehicle 1 from the estimated sun position (S45).

  The parameter control unit 12 determines whether or not the shadow of the identified vehicle 1 is in the immediately preceding area 4 (S46). If it is determined that the shadow of the identified vehicle 1 is not in the immediately preceding area 4 (S46: NO), the parameter control unit 12 sets a photometric area in the area H shown in FIG. 7 (S50). At this time, if the parameter control unit 12 determines that the current weather is rainy or cloudy from the acquired weather information, the parameter control unit 12 determines that there is no difference in brightness between the shadowed part and the non-shadowed part. A photometric area may be set. Then, the parameter control unit 12 ends this operation.

  If the parameter control unit 12 determines that the shadow of the specified vehicle 1 is in the immediately preceding area 4 (S46: YES), the parameter control unit 12 determines whether the shadow of the vehicle 1 is larger than a predetermined value (S47). When it determines with it being larger than predetermined (S47: YES), the parameter control part 12 sets the shadow part of the vehicle 1 to a photometry area | region (S48). Then, the parameter control unit 12 ends this operation. On the other hand, when it is determined that the shadow range is smaller than the predetermined range (S47: NO), the parameter control unit 12 sets the photometric area so that the shadow of the vehicle 1 is removed (S49). Then, the parameter control unit 12 ends this operation. Thus, by setting the photometry area in consideration of the shadow of the vehicle 1, the brightness of the photometry area becomes substantially equal, and the image processing unit 11 detects the paint display from the image of the portion corresponding to the photometry area. It becomes easy.

  In S31, when the parameter control unit 12 finishes the photometry area setting process, the photometry calculation unit 22 of the in-vehicle camera 20 performs photometry for the set photometry area (S32). The in-vehicle camera 20 performs exposure control by the exposure / gain control unit 24 (S33).

  Next, the camera ECU 10 performs a paint display detection process (S34). The paint display detection process is the same as the object detection process of the first embodiment, and a description thereof will be omitted. Subsequently, the camera ECU 10 determines whether or not a paint display is detected (S35). When the paint display is detected (S35: YES), the monitor 30 is turned on and the captured image is displayed on the monitor 30 (S36). That is, even if the display switch 31 is off, if a paint display appears in front of the vehicle 1, the camera ECU 10 forcibly displays a captured image immediately before the vehicle. Thus, for example, when the paint display “stop” is detected before the intersection, the driver displays an image on the monitor 30 when leaving the vehicle before stopping at the intersection or during low-speed driving. The area 4 immediately before the vehicle 1 can be confirmed, and an accident can be avoided.

  Thereafter, the process proceeds to S29. On the other hand, when the paint display is not detected (S35: NO), the process proceeds to S29. It should be noted that the operation of FIG. 9 is forcibly terminated when the engine is turned off even during the processing.

  As described above, by setting the photometry area in consideration of the shadow of the vehicle 1, the brightness of the photometry area becomes substantially equal, and the image processing of the image corresponding to the photometry area is facilitated. In addition, for example, when a paint display such as “stop” that issues a warning before an intersection is detected, the monitor 30 can be forcibly turned on so that the area 4 immediately before the driver ’s blind spot can be confirmed on the monitor 30. Sometimes accidents near intersections can be avoided.

It is a block diagram which shows typically the function which the vehicle periphery monitoring device concerning an embodiment has. It is a schematic diagram for demonstrating the photometry area | region set with respect to the imaging range of a vehicle-mounted camera, (a) is the figure seen from the vehicle upper direction, (b) is the figure seen from the vehicle side. is there. It is a schematic diagram for demonstrating the photometry area | region set with respect to the imaging range of a vehicle-mounted camera. It is a flowchart which shows operation | movement of a vehicle periphery monitoring apparatus. It is a schematic diagram of another example for demonstrating the photometry area | region set with respect to the imaging range of a vehicle-mounted camera. It is a block diagram which shows typically the function which the vehicle periphery monitoring device concerning this embodiment has. It is a schematic diagram for demonstrating the photometry area | region set with respect to the imaging range of a vehicle-mounted camera, when there is no shadow of a vehicle, (a) makes a part of road a photometry area, (b) The case where the entire road is used as a photometric area is shown. It is a schematic diagram for demonstrating the photometry area | region set with respect to the imaging range of a vehicle-mounted camera in case there exists a vehicle shadow, (a) shows a case where a shadow is small, (b) shows a case where a shadow is large. . It is a flowchart which shows operation | movement of a vehicle periphery monitoring apparatus. It is a flowchart which shows the operation | movement of a photometry area | region setting process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Front left area 3 Front right area 4 Right front area 20 Car-mounted camera 21 Image sensor 30 Monitor A, B, C area | region

Claims (7)

An imaging unit that is installed in a vehicle and that images the periphery of the vehicle, a photometric unit that performs photometry in a photometric area set within an imaging range of the imaging unit, and the imaging unit based on a photometric result by the photometric unit In a vehicle periphery monitoring device comprising exposure control means for performing exposure control of
Designating means for designating a plurality of different areas within the imaging range;
A vehicle periphery monitoring device comprising: setting means for setting one of the areas designated by the designation means to the photometric area at a predetermined timing. The imaging means includes
It is installed in the vehicle so that it can image the front of the vehicle,
The designation means is:
A first area corresponding to a predetermined distance forward from the front of the vehicle and a second area corresponding to the left and right front from the front of the vehicle and different from the first area are designated within the imaging range. The vehicle periphery monitoring device according to claim 1, wherein: A display unit that is installed so as to be visible to the driver and displays a captured image captured by the imaging unit;
A switch for turning on / off the display means;
An object detection means for detecting an object in the first region,
The setting means includes
When the switch is on, the second area is set as the photometry area, and when the switch is off, the first area is set as the photometry area.
The vehicle periphery monitoring device according to claim 2, further comprising switch control means for forcibly turning on the switch when the object detection means detects an object when the switch is off. The imaging means includes
It is installed in the vehicle so that it can image the front of the vehicle,
The designation means is:
The vehicle periphery monitoring device according to claim 1, wherein a paint display area including a paint display provided on a road surface of a road in front of the vehicle is designated within the imaging range. A display unit that is installed so as to be visible to the driver and displays a captured image captured by the imaging unit;
A switch for turning on / off the display means;
And paint display detection means for detecting paint display in the paint display area,
The setting means includes
When the switch is off, the paint display area is set as the photometry area,
The vehicle periphery monitoring device according to claim 4, further comprising switch control means for forcibly turning on the switch when the paint display detection detects a paint display when the switch is off. . A specifying means for specifying the position of the shadow of the own vehicle;
The setting means includes
When the photometric area is set to the first area or the paint display area, the photometric area is set to a part or all of the first area or the paint display area according to the position of the shadow specified by the specifying unit. The vehicle periphery monitoring device according to any one of claims 2 to 5, wherein the vehicle periphery monitoring device is configured as described above. The object detection means includes
The vehicle periphery monitoring apparatus according to claim 3, wherein a difference between captured images captured with a time difference is taken by the imaging unit and detected based on a result of the difference.

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