JP2008230464A - Automatic exposure device for on-vehicle camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide "an automatic exposure device for an on-vehicle camera" capable of making luminosity of an image in a range used in the photographed image of the on-vehicle camera to appropriate luminosity regardless of the traveling state at night of the vehicle provided with a luminous intensity distribution variable type headlight system. <P>SOLUTION: In a light measurement area setting means 38 for setting a light measurement area of the on-vehicle camera 15, the light measurement areas 7, 41 can be changed according to variation of an irradiation area photographing range 40 used for photographing of an irradiation area of the headlight 25 in the photographing range 1 of the on-vehicle camera 15 accompanying with variation of a steering angle of a steering wheel 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an in-vehicle camera automatic exposure device, and more particularly to an in-vehicle camera automatic exposure device suitable for performing automatic exposure of a camera (hereinafter referred to as an in-vehicle camera) mounted on a host vehicle.

  In recent years, as a technology using an in-vehicle camera, vehicle periphery monitoring for displaying a vehicle periphery monitoring image for monitoring a predetermined monitoring range in the vicinity of the host vehicle using a captured image of a road surface or the like by the in-vehicle camera on a display in the vehicle The device came to be adopted.

  As a vehicle-mounted camera used for such a vehicle periphery monitoring device, a camera equipped with a super wide-angle lens such as a fisheye lens is generally used.

  In such a vehicle periphery monitoring device, for example, a range table (image such as a road surface) used for generating a vehicle periphery monitoring image in an image captured by an in-vehicle camera is converted into a conversion table called a mapping table. The vehicle periphery monitoring image is generated by converting (coordinate conversion) from an image on the camera (imaging surface) coordinate system to an image on the display coordinate system.

  Conventionally, in an in-vehicle camera used in such a vehicle periphery monitoring device, when performing auto exposure (AE), an imaging range of the in-vehicle camera (in other words, photoelectric conversion on the CCD light receiving surface is performed). In other words, photometry is performed with the entire imaging range as a photometric area while placing a weight on the center of the effective pixel area. Such a photometric method has been called center-weighted metering.

  For example, when generating a left side view image for monitoring the left front of the host vehicle as an example of a vehicle periphery monitoring image during night driving, for example, the left as an in-vehicle camera attached to a left door mirror or the like Although the side camera has imaged the road surface on the left side of the host vehicle, as shown in FIG. 7, within the imaging range 1 of the left side camera, the left side view image of the road surface, the left side of the host vehicle, etc. In addition to objects necessary for generation, unnecessary objects such as the sky and buildings were sometimes captured.

  Therefore, conventionally, as an irradiation range of the infrared LED illumination mounted on the left side camera, first, the entire imaging range 1 is placed while placing a weight on the central portion 2 (within the broken line frame in FIG. 7) in the imaging range 1 of the in-vehicle camera. The exposure is automatically determined by performing photometry in the photometry area 3, and an object captured in the imaging range 1 is imaged under the determined exposure.

  And among the captured images, an image including the road surface on the left front side of the host vehicle and a part of the host vehicle, that is, an image captured in a part of the imaging range 4 surrounded by a one-dot chain line in FIG. The left side view image is generated by converting the coordinates of the image using a mapping table. The part of the imaging range 4 is distorted into a barrel shape because the distortion of the super wide-angle lens mounted on the left side camera is taken into consideration. On the other hand, images of unnecessary objects such as the sky and buildings in the captured images are discarded.

  However, when the entire imaging range 1 is set to the photometric area 3 as described above, not only the brightness of an unnecessary object such as the sky is considered but also the left side view image is generated when determining the exposure. Metering with sufficient consideration of the brightness of the object (road surface, etc.) used in

  That is, as shown in FIG. 7, when the road surface is imaged at night by the left side camera, a sky that is much darker than the road surface is captured in the imaging range 1, but in such a situation, When photometry is performed with a weight on the central portion 2 of the imaging range 1, the brightness of the object captured in the imaging range 1 is averagely dark (darker than the road surface) because of the darkness of the sky. It was judged.

  As a result, in the case of FIG. 7, the exposure is determined so that the picked-up image of the road surface is brighter (over) than necessary.

  Then, the left side view image generated based on the captured image captured after determining the exposure in this way and displayed on the display is a rough side view image with a very bright road surface as shown in FIG. It was five.

  Therefore, in order to correct such a problem, the applicant of the present application disclosed in Japanese Patent Application No. 2006-133747 an area that matches or approximates the range used for imaging an image in the imaging range of the in-vehicle camera. An auto-exposure device for in-vehicle cameras that sets a photometric area with a range was proposed.

  According to such an on-vehicle camera automatic exposure device, for example, as shown in a region within a solid line frame in FIG. 9, an image (road surface) used for generating a left side view image in the imaging range 1 of the left side camera. By setting a photometric area 7 having an area range that approximates a part of the imaging range 4 used for imaging (such as an image of the image etc.), photometry excluding the brightness of unnecessary objects such as the sky was possible. .

  In FIG. 9, as a minimum unit for setting the photometric area 7, imaging is performed for each pixel group 8 that is a set of pixels of vertical multiple dots (for example, 15 dots) × horizontal multiple dots (for example, 20 dots). Range 1 is demarcated.

JP-A-9-142210

  By the way, in recent years, a headlight system called an AFS (Adaptive Front Lighting System) or a light distribution variable type headlight system has come to be used in vehicles.

  This headlamp system is adapted to follow the direction of headlamp light irradiation (in other words, the direction of the optical axis) in the steering direction of the steering wheel of the vehicle. Even when traveling on a curve, it is possible to maintain a state in which the light of the headlamp is irradiated in front of the traveling direction of the host vehicle.

  Here, in a vehicle equipped with this type of variable light distribution type headlamp system, as shown in FIG. 10, when the vehicle turns left or curves in the left direction, it is within the imaging range 1 of the left side camera. An area (hereinafter referred to as an irradiation area 10) irradiated with light from the headlamp (left headlamp in FIG. 10) may be captured.

  On the other hand, during straight running, the irradiation area 10 is hardly captured in the imaging range 1 of the left side camera.

  Therefore, if the photometry area 7 set during the straight running is applied as it is during the curve running, there is a possibility that the photometry taking into account the brightness of the irradiation area 10 cannot be performed sufficiently, as shown in FIG. There is a possibility that a rough left side view image 11 in which a portion corresponding to the irradiation region 10 is brighter than necessary (overexposed) is generated.

  Therefore, the present invention has been made in view of the above points, and is a range to be used in a captured image of an in-vehicle camera regardless of the running state of the host vehicle equipped with the variable light distribution headlight system at night. It is an object of the present invention to provide an in-vehicle camera automatic exposure device capable of setting the brightness of the image to an appropriate brightness.

  In order to achieve the above-described object, an on-vehicle camera automatic exposure device according to the present invention causes the traveling direction of the host vehicle to follow the irradiation direction of the headlamp light of the host vehicle in accordance with the steering direction of the handle of the host vehicle. An in-vehicle camera that is mounted on a host vehicle equipped with a variable light distribution type headlamp system that maintains a state in which the light of the headlamp is irradiated, and that captures a predetermined area around the host vehicle, A photometric area setting means for setting a photometric area to be used for automatic exposure of the camera, such that an image in a range to be used in a captured image of the in-vehicle camera is an image captured under appropriate exposure; and the handle Steering angle / irradiation direction information acquisition means for acquiring at least one of information regarding the steering angle of the steering wheel and information regarding the irradiation direction of the light of the headlamp corresponding to the steering angle of the steering wheel, and the steering / Based on the acquisition information of the irradiation direction information acquisition means, imaging of the in-vehicle camera with respect to an irradiation area imaging range that is a range used for imaging the area irradiated with the light of the headlamp in the imaging range of the in-vehicle camera Irradiation area imaging range estimation means for estimating the occupation range within the range including the presence / absence of the irradiation area imaging range within the imaging range of the in-vehicle camera, and the photometric area setting means determines the steering angle of the steering wheel The photometric area is formed so as to be changeable according to a change in an estimation result of the irradiation area imaging range estimation means according to a change.

  According to such a configuration, even if there is a change in the occupation range (including presence / absence) of the irradiation area imaging range in the imaging range of the in-vehicle camera with a change in the steering angle of the steering wheel, the change follows. Thus, it is possible to change the photometric area so that the image in the range to be used in the captured image of the in-vehicle camera becomes an image captured under appropriate exposure.

  Further, in another on-vehicle camera automatic exposure apparatus according to the present invention, the photometric area setting means has a ratio of an area of the irradiation area imaging range included in the photometric area to an area of the entire photometric area as the photometric area. It is characterized in that it is formed so as to set a photometric area that is equal to or greater than a predetermined threshold.

  And according to such a structure, it becomes possible to set the photometry area | region which fully considered the brightness of the irradiation area | region.

  Furthermore, in the other on-vehicle camera automatic exposure device according to the present invention, the image of the used range is used to generate a vehicle periphery monitoring image for monitoring a predetermined monitoring range around the host vehicle. It is characterized by being a range image.

  According to such a configuration, the vehicle periphery monitoring image in the captured image of the in-vehicle camera regardless of the change in the occupation range of the irradiation region imaging range in the imaging range of the in-vehicle camera due to the change in the steering angle of the steering wheel. It is possible to maintain a state in which an image in a range used for generating the image becomes an image captured under appropriate exposure.

  Furthermore, in another automatic exposure device for an in-vehicle camera according to the present invention, the in-vehicle camera is a side camera attached to a side portion of the own vehicle, and the vehicle periphery monitoring image is a front side of the own vehicle. It is characterized by being a side view image for monitoring.

  According to such a configuration, the side view image of the captured image of the in-vehicle camera is not affected by the change in the occupation range of the irradiation region imaging range in the imaging range of the in-vehicle camera due to the change in the steering angle of the steering wheel. It is possible to maintain a state in which an image in a range used for generation is an image captured under appropriate exposure.

  Further, in the other in-vehicle camera automatic exposure device according to the present invention, when the photometry area setting means obtains an estimation result corresponding to the straight traveling state of the own vehicle by the irradiation area imaging range estimation means. The photometric area is set to a photometric area having an area range that matches or approximates a range used for imaging an image of the used range in the imaging range of the in-vehicle camera, and the irradiation area imaging range estimation means When the estimation result corresponding to the curved traveling state of the host vehicle is obtained, the irradiation area imaging range is compared with the photometric region when the estimation result corresponding to the straight traveling state of the host vehicle is obtained. It is characterized in that it is formed so as to set a photometric area shifted in the direction.

  And according to such a structure, in order to make the image of the range used for the production | generation of the side view image in the picked-up image of a vehicle-mounted camera become an image imaged under appropriate exposure, it is still more suitable photometry area | region Can be set.

  According to the automatic exposure device for an in-vehicle camera according to the present invention, even if there is a change in the occupation range (including presence / absence) of the irradiation area imaging range in the imaging range of the in-vehicle camera with a change in the steering angle of the steering wheel, Following this variation, the photometry area can be changed so that the image in the range used in the image captured by the in-vehicle camera becomes an image captured under proper exposure. As a result, the variable light distribution type headlamp system Regardless of the driving state of the vehicle equipped with the vehicle at night, the brightness of the image in the used range in the captured image of the in-vehicle camera can be set to an appropriate brightness.

  In addition, according to the other on-vehicle camera automatic exposure device according to the present invention, it is possible to set a photometric area that sufficiently considers the brightness of the irradiation area. The brightness of the can be further moderated.

  Furthermore, according to the other on-vehicle camera automatic exposure device according to the present invention, the on-vehicle camera can be used regardless of the change in the occupancy range of the irradiation area imaging range within the imaging range of the on-vehicle camera accompanying the change of the steering angle of the steering wheel. As a result, it is possible to maintain a state in which the image in the range used for generating the vehicle periphery monitoring image in the captured image becomes an image captured under appropriate exposure, and as a result, a favorable vehicle having no brightness abnormality such as overexposure A peripheral monitoring image can be obtained.

  Furthermore, according to the other on-vehicle camera automatic exposure device according to the present invention, the vehicle-mounted camera can be used regardless of the change in the occupying range of the irradiation area imaging range within the imaging range of the on-vehicle camera accompanying the change of the steering angle of the steering wheel. As a result of maintaining the state in which the image in the range used for generating the side view image in the captured image of the camera becomes an image captured under appropriate exposure, there is no abnormality in brightness such as overexposure A view image can be obtained.

  Further, according to another on-vehicle camera automatic exposure device according to the present invention, an image in a range used for generating a side view image in a captured image of the in-vehicle camera is an image captured under appropriate exposure. As a result, a more suitable photometry area can be set, and as a result, a better side view image can be obtained.

  Hereinafter, an embodiment of an automatic exposure device for a vehicle-mounted camera according to the present invention will be described with reference to FIGS.

  Note that portions that have the same or similar basic configuration as those in the related art will be described using the same reference numerals.

  FIG. 1 shows a vehicle periphery monitoring device 14 equipped with an in-vehicle camera automatic exposure device in the present embodiment.

  The vehicle periphery monitoring device 14 includes a left side camera 15 attached to a left side portion (for example, a left door mirror) of the host vehicle as an in-vehicle camera, and the left side camera 15 is a self-portrait around the host vehicle. An object existing in a region within a predetermined viewing angle (view angle) around the left side of the vehicle is imaged. The left side camera 15 constitutes a part of an in-vehicle camera automatic exposure device.

  An ECU (Electronic Control Unit) 16 is connected to the left side camera 15 via a communication connection means 17 such as a cable. A display 20 is connected to the ECU 16 via a communication connection means 18 such as a cable. It is connected.

  The ECU 16 is input with data of a captured image of the left side camera 15.

  Then, the ECU 16 generates and generates a left side view image for monitoring the left front (front side) of the host vehicle as a vehicle periphery monitoring image based on the captured image data input from the left side camera 15. The displayed left side view image is displayed on the display 20.

  Further, as shown in FIG. 1, a steering angle detection sensor 22 disposed on the handle 21 of the host vehicle is connected to the ECU 16 via communication connection means 23 such as a cable. 22 detects the steering angle of the steering wheel 21.

  Furthermore, a left headlamp 25 and a right headlamp 26 are connected to the ECU 16 via communication connection means 24 such as a cable.

  Next, FIG. 2 shows the configuration of FIG. 1 in more detail. As shown in FIG. 2, the ECU 16 has a left side camera image input unit 27. This left side camera image The left side camera 15 is connected to the input side of the input unit 27. Data of the captured image of the left side camera 15 is input to the left side camera image input unit 27 as analog data. The left side camera image input unit 27 performs A-D conversion on the input image data of the left side camera 15 and outputs the converted image data to the ECU 16.

  A camera image acquisition unit 28 is connected to the output side of the left side camera image input unit 27, and the camera image acquisition unit 28 receives data of the captured image of the left side camera 15 from the left side camera image input unit 27. To get to.

  A left side view image generation unit 30 is connected to the output side of the camera image acquisition unit 28, and the left side view image generation unit 30 captures an image of the left side camera 15 acquired by the camera image acquisition unit 28. Image data is input.

  A data storage unit 31 is connected to the left side view image generation unit 30, and the data storage unit 31 describes the correspondence between the coordinates of the pixels of the captured image of the left side camera 15 and the left side view image. Stored mapping table is stored.

  Then, the left side view image generation unit 30 reads the mapping table stored in the data storage unit 31 and performs coordinate conversion on the captured image of the left side camera 15 using the read mapping table. A left side view image is generated.

  In the mapping table, the image in the range used for generating the left side view image among the captured images of the left side camera 15 is defined as a state in which the coordinates of the pixels on the camera (imaging plane) coordinate system are designated. The captured image of the left side camera 15 that is not described in the mapping table is discarded without being used for generating the left side view image.

  The display 20 described above is connected to the output side of the left side view image generation unit 30, and data of the left side view image generated by the left side view image generation unit 30 is output to the display 20. It is like that.

  In this way, the left side view image is displayed on the display 20.

  The ECU 16 also has an AFS control unit 34. The steering angle detection sensor 22 described above is provided on the input side of the AFS control unit 34, and the left headlight 25 and the right headlamp described above are provided on the output side. 26 are connected to each other.

  As shown in FIG. 2, the left headlamp 25 is driven by the left headlamp actuator 25a connected to the AFS control unit 34, and the left headlamp actuator 25a changes the light irradiation direction to the left and right (vehicles). And a left headlamp body 25b deflected in the width direction.

  Similarly, the right headlamp 26 includes a right headlamp actuator 26a connected to the AFS control unit 34, and a right headlamp body 26b that is driven by the right headlamp actuator 26a to deflect the light irradiation direction to the left and right. And is composed of.

  The steering angle detection sensor 22, the left headlamp 25, the right headlamp 26, and the AFS control unit 34 constitute an AFS as a variable light distribution type headlamp system.

  In other words, the steering angle data of the steering wheel 21 detected by the steering angle detection sensor 22 (hereinafter referred to as steering angle data) is input to the AFS control unit 34 from the steering angle detection sensor 22 side. Yes.

  Based on the steering angle data, the AFS control unit 34 drives the headlamp actuators 25a and 26a so that the light irradiation directions of the headlamps 25 and 26 follow the steering direction of the handle 21 ( In the following, the head drive actuators 25a and 26a are driven and controlled according to the determined actuator drive amount.

  Thereby, irrespective of the change of the steering angle of the steering wheel 21, it is possible to maintain the state in which the lights of the headlamps 25 and 26 are irradiated in front of the traveling direction of the host vehicle.

  An AFS information acquisition unit 36 as a steering angle / irradiation direction information acquisition unit is connected to the AFS control unit 34, and the AFS information acquisition unit 36 receives information from the AFS control unit 34 as information regarding the steering angle of the handle 21. The steering angle data is acquired.

  Note that the AFS control unit 34 provides information regarding the irradiation direction of the lights of the headlamps 25 and 26 corresponding to the steering angle of the handle 21 from the AFS information acquisition unit 36 together with or instead of the steering angle data. The actuator drive amount data described above may be acquired.

  The AFS information acquisition unit 36 is connected to an irradiation region imaging range estimation unit 37 that constitutes a part of the irradiation region imaging range estimation unit. The irradiation region imaging range estimation unit 37 includes the AFS information acquisition unit 36. Acquisition information is entered.

  The irradiation region imaging range estimation unit 37 is connected to the data storage unit 31 described above, and the data storage unit 31 is irradiated with light of the left headlamp 25 in the imaging range of the left side camera 15. 10 (refer to FIG. 10), irradiation area imaging range data (hereinafter referred to as irradiation area imaging range data), which is a range used for imaging, is stored as a state (for example, a table) having a correspondence relationship with the steering angle data. Yes. Such a data storage unit 31 constitutes an irradiation region imaging range estimation unit together with the irradiation region imaging range estimation unit 37.

  The data storage unit 31 may store the irradiation area imaging range data in a state having a corresponding relationship with the actuator drive amount data, or the irradiation area imaging range data may be stored in the actuator. It may be stored as a state having a correspondence with only the driving amount data.

  In this way, the irradiation area imaging range estimation means configured by the irradiation area imaging range estimation unit 37 and the data storage unit 31 is based on the acquisition information input from the AFS information acquisition unit 36 and the left side camera 15. The occupying range of the irradiation region imaging range within the imaging range 1 (in other words, the size, shape, and position occupied by the irradiation region imaging range with respect to the entire imaging range 1) is estimated.

  The estimation of the occupation range of the irradiation region imaging range includes estimation of the existence or nonexistence of the irradiation region imaging range within the imaging range of the left side camera 15 (that is, the presence or absence of the occupation range).

  The irradiation area imaging range estimation means will be described in more detail. When the steering angle data is input from the AFS information acquisition unit 36, the irradiation area imaging range estimation unit 37 reads and reads the irradiation area imaging range data from the data storage unit 31. The emitted irradiation area imaging range data is compared with the steering angle data input from the AFS information acquisition unit 36.

  Based on the result of this comparison, the irradiation region imaging range estimation unit 37 estimates the occupation range of the irradiation region imaging range within the imaging range of the left side camera 15 including the presence or absence thereof.

  And the irradiation area imaging range estimation part 37 outputs the data of the estimation result of the occupation range of such an irradiation area imaging range.

  The irradiation area imaging range estimation unit 37 compares the irradiation area imaging range data read from the data storage unit 31 with the actuator driving amount data input from the AFS information acquisition unit 36 to thereby determine the left side. The occupation range of the irradiation area imaging range within the imaging range of the camera 15 may be estimated.

  A photometric area setting unit 38 as a photometric area setting unit is connected to the output side of the irradiation area imaging range estimation unit 37, and the photometric area setting unit 38 outputs the irradiation area imaging range estimation unit 37. The estimation result data is input.

  The photometric area setting unit 38 is used to generate a left side view image in the captured image of the left side camera 15 as a photometric area used for automatic exposure of the left side camera 15 based on the input estimation result data. The photometric area is set so that the image in the range to be captured is an image captured under appropriate exposure.

  Further, the photometric area setting unit 38 changes the photometric area to be set in accordance with the change in the estimation result of the irradiation area imaging range estimation unit 37 accompanying the change in the steering angle of the handle 21.

  More specifically, the photometry area setting unit 38 according to the present embodiment receives the estimation result data corresponding to the straight running state of the host vehicle from the irradiation area imaging range estimation unit 37, as shown in FIG. As shown in a), a photometric area 7 having an area range that approximates a part of the imaging range 4 used for imaging an image used for generating a left side view image in the imaging range 1 of the left side camera 15 is shown. It is supposed to be set. In this embodiment, the estimation result of the irradiation area imaging range estimation unit 37 corresponding to the straight traveling state of the host vehicle is within the imaging range 1 of the left side camera 15 as shown in FIG. The estimation result indicates that the imaging range will not exist, in other words, that the irradiation area 10 will not be captured within the imaging range 1 of the left side camera 15.

  On the other hand, the photometric area setting unit 38 receives from the irradiation area imaging range estimation unit 37 data of estimation results corresponding to a curve traveling state (for example, a left turn or a leftward curve traveling) of the host vehicle. When input, as shown in FIG. 3B, the photometric area 41 shifted in the direction of the irradiation area imaging range 40 is set with respect to the photometric area 7 shown in FIG. It has become. In the present embodiment, the estimation result of the irradiation area imaging range estimation unit 37 corresponding to the curved traveling state of the host vehicle is within the imaging area 1 of the left side camera 15 as shown in FIG. The imaging range 40 will exist in a predetermined occupation range corresponding to the steering angle, in other words, the irradiation region 10 having a predetermined size and shape at a predetermined position in the imaging range 1 of the left side camera 15. It is assumed that the estimation result indicates that will be captured. The photometric area setting unit 38 may set the photometric area 41 as shown in FIG. 3B after confirming the lighting state of the left headlamp 25.

  Therefore, according to the present embodiment, even if a change occurs in the occupation range (including presence / absence) of the irradiation region imaging range 10 in the imaging range 1 of the left side camera 15 with a change in the steering angle of the handle 21, Following this change, the photometric area can be changed so that the image in the range used for generating the left side view image in the captured image of the left side camera 15 becomes an image captured under appropriate exposure.

  Furthermore, in the present embodiment, the ratio of the area of the irradiation area imaging range 40 included in the photometric area 41 to the total area of the photometric area 41 in the photometric area 41 in the curved traveling state of the host vehicle is equal to or greater than a predetermined threshold. A photometric area 41. This threshold value can be appropriately changed according to the concept. In FIG. 3B, the irradiation area imaging range 40 is completely included in the photometry area 41.

  Therefore, according to the present embodiment, it is possible to set the photometric area 41 that fully considers the brightness of the irradiation area 10.

  By the way, the occupation range of the irradiation area imaging range 40 in the imaging range 1 of the left side camera 15 described above, that is, the position and size of the irradiation area 10 in the imaging range 1 of the left side camera 15 are determined by the steering angle of the handle 21. It continuously fluctuates according to the change of.

  For example, at the time of a left turn, the irradiation region imaging range 40 shows a continuous fluctuation that gradually moves to the left in the imaging range 1 as the handle 21 is turned to the left.

  Therefore, in order to cope with the continuous variation of the occupation range of the irradiation region imaging range 40, the photometry region setting unit 38 follows the continuous variation of the irradiation region imaging range 40 for the photometry region 41 to be set. And it is supposed to change continuously.

  Thereby, it is possible to set the photometric area 41 in which the brightness of the irradiation area 10 is more fully considered.

  In the present embodiment, the photometry area setting unit 38 outputs the photometry area data set in this way to the left side camera 15.

  Next, the left side camera 15 will be described in detail. As shown in FIG. 4, the left side camera 15 has a super-wide-angle lens 46, and the super-wide-angle lens 46 collects light incident from the outside. It is supposed to be.

  The left side camera 15 has a CCD (Charged Coupled Device) 47, and the light collected by the super wide-angle lens 46 is coupled to the light receiving surface of the CCD 47. Yes.

  The CCD 47 photoelectrically converts the light coupled to the light receiving surface into RAW data (raw data) and outputs it further to the left side camera 15.

  An AFE (Analog Front End) 49 is connected to the output side of the CCD 47, and RAW data output from the CCD 47 is input to the AFE 49.

  The AFE 49 includes a CDS (Cor-related Double Sampling) circuit 53, an AGC (Auto Gain Control) circuit 54 connected to the subsequent stage of the CDS circuit 53, and an A / D converter ( A / D 55) and a TG (Timing Generator) 56.

  The CDS circuit 53 performs a process for removing noise from the RAW data input from the CCD 47 and outputs the processed RAW data to the AGC circuit 54.

  The AGC circuit 54 performs automatic exposure of the left side camera 15 by controlling the input gain when the A / D 55 in the subsequent stage performs A / D conversion of the RAW data to a value corresponding to the determined exposure. It has become.

  The A / D 55 performs A / D conversion of the RAW data under the control of the input gain by the AGC circuit 54 and outputs it from the AFE 49.

  The TG 56 drives a horizontal CCD in the CCD 47.

  A digital signal processor (DSP) 50 is connected to the AFE 49, and the A / D-converted RAW data output from the A / D 55 is input to the DSP 50.

  The DSP 50 converts the RAW data into a YUV signal and outputs it by performing signal processing and correction (γ correction, etc.) on the input RAW data.

  The DSP 50 is configured to receive the photometry area data output by the photometry area setting unit 38. The DSP 50 performs photometry using the photometry area according to the input photometry area data to determine exposure, and information about the determined exposure (hereinafter referred to as exposure information) is used for the AGC circuit 54 of the AFE 49. To output.

  Here, since the exposure determined by the DSP 50 is based on the photometry area set by the photometry area setting unit 38, an image in a range used for generating the left side view image in the captured image of the left side camera 15 is selected. The exposure is such that an image can be taken under appropriate exposure. Specifically, the exposure determined by the DSP 50 faithfully reflects the actual brightness of the road surface in consideration of the brightness of the irradiation region 10 when imaging the road surface in FIGS. 3 (a) and 3 (b). The exposure can be reflected.

  A video encoder 51 is connected to the output side of the DSP 50, and the YUV signal output from the DSP 50 is input to the video encoder 51.

  The video encoder 51 converts the input YUV signal into an NTSC (National Television Standards Committee) signal by DA conversion and outputs it to the ECU 16. This NTSC signal is the image data of the left side camera 15.

  In addition, in the present embodiment, a V-Driver 57 is connected between the TG 56 of the AFE 49 and the CCD 47, and the V-Driver 57 converts the voltage level of the output voltage of the TG 56 and uses the converted voltage. Thus, the vertical CCD in the CCD 47 is driven.

  Next, the operation of this embodiment will be described.

  First, as shown in FIG. 5 (a), when the host vehicle 60 is traveling on a straight road 61 with the headlamps 25 and 26 turned on, the user does not show a push button or a remote controller, for example. It is assumed that an input operation for displaying the left side view image is performed on the ECU 16 by using the input device.

  By this input operation, the AFS information acquisition unit 36 acquires the steering angle data from the AFS control unit 34, and outputs the acquired steering angle data to the irradiation region imaging range estimation unit 37.

  Next, when the steering angle data output from the AFS information acquisition unit 36 is input, the irradiation region imaging range estimation unit 37 reads the irradiation region imaging range data from the data storage unit 31 and reads the read irradiation region imaging range. The data is compared with the steering angle data input from the AFS information acquisition unit 36.

  Next, based on the result of this comparison, the irradiation area imaging range estimation unit 37 estimates the occupation range of the irradiation area imaging range within the imaging range of the left side camera 15 including the presence or absence thereof.

  At this time, since the host vehicle 60 is in a straight running state, it is estimated that there is no irradiation area imaging range in the imaging range 1 of the left side camera 15 as shown in FIG.

  Then, the irradiation area imaging range estimation unit 37 outputs estimation result data indicating that such an irradiation area imaging range does not exist to the photometry area setting unit 38.

  Next, the photometric area setting unit 38, based on the estimation result data output from the irradiation area imaging range estimation unit 37, the left side view image in the imaging range 1 of the left side camera 15 as shown in FIG. A photometric area 7 having an area range that approximates a part of the imaging range 4 used for imaging an image used for generating the image is set.

  Next, the photometry area setting unit 38 outputs the set data of the photometry area 7 to the DSP 50 of the left side camera 15.

  Next, the DSP 50 performs photometry using the photometry area 7 according to the data of the photometry area 7 output from the photometry area setting unit 38 to determine the exposure, and uses the exposure information of the determined exposure as the AGC circuit 54 of the AFE 49. Output to.

  Next, the AGC circuit 54 controls the value of the input gain when A / D converting the RAW data input from the CCD 47 according to the exposure information output by the DSP 50.

  Thereby, the automatic exposure in the straight running state of the own vehicle 60 is performed.

  Next, the A / D 55 outputs the RAW data after performing the A / D conversion under such automatic exposure to the DSP 50.

  Next, the DSP 50 converts the RAW data output from the A / D 55 into a YUV signal and outputs the YUV signal to the video encoder 51.

  Next, the video encoder 51 converts the RAW data output from the DSP 50 into an NTSC signal, and outputs this to the ECU 16 as data of a captured image of the left side camera 15.

  Data of the captured image of the left side camera 15 output from the left side camera 15 to the ECU 16 is input to the left side camera image input unit 27 and is A / D converted by the left side camera image input unit 27.

  Next, the camera image acquisition unit 28 acquires data of the captured image of the left side camera 15 from the left side camera image input unit 27 and outputs the acquired data to the left side view image generation unit 30.

  Next, the left side view image generation unit 30 reads the mapping table from the data storage unit 31 when the data of the captured image of the left side camera 15 output from the camera image acquisition unit 28 is input.

  Then, the left side view image generation unit 30 uses the mapping table read from the data storage unit 31 to perform coordinate conversion on the captured image of the left side camera 15 input from the camera image acquisition unit 28 side. The left side view image is generated, and the generated left side view image is displayed on the display 20.

  Thereby, the left side view image of moderate brightness can be displayed on the display 20 in the straight traveling state of the host vehicle 60.

  Next, as shown in FIG. 5B, when the host vehicle 60 is traveling on the left curve road 62 with the headlamps 25 and 26 turned on, the user uses an input device (not shown). Assume that an input operation for displaying the left side view image is performed on the ECU 16.

  By this input operation, the AFS information acquisition unit 36 acquires the steering angle data from the AFS control unit 34, and outputs the acquired steering angle data to the irradiation region imaging range estimation unit 37.

  Next, when the steering angle data output from the AFS information acquisition unit 36 is input, the irradiation region imaging range estimation unit 37 reads the irradiation region imaging range data from the data storage unit 31 and reads the read irradiation region imaging range. The data is compared with the steering angle data input from the AFS information acquisition unit 36.

  Next, based on the result of this comparison, the irradiation area imaging range estimation unit 37 estimates the occupation range of the irradiation area imaging range within the imaging range of the left side camera 15 including the presence or absence thereof.

  At this time, since the host vehicle 60 is in a curved traveling state, as shown in FIG. 3B, the irradiation area imaging range 40 of a predetermined occupation range corresponding to the steering angle within the imaging range 1 of the left side camera 15. Is presumed to exist.

  Then, the irradiation area imaging range estimation unit 37 outputs estimation result data indicating that such an irradiation area imaging range 40 exists to the photometry area setting unit 38.

  Next, the photometry area setting unit 38 is based on the estimation result data output from the irradiation area imaging range estimation unit 37, and the irradiation area imaging range is higher than the photometry area 7 in the straight traveling state as shown in FIG. The photometric area 41 shifted to the 40 side is set.

  Since the operation of the vehicle periphery monitoring image 14 after the photometric area 41 is set is the same as that in the case of the straight running state, detailed description is omitted, but the automatic exposure using the photometric area 41 set in this way is omitted. By taking an image below and using the captured image for generating the left side view image, the display 20 is appropriately reflected in the brightness of the actual road surface where the irradiation area 10 as shown in FIG. The left side view image 64 that is bright can be displayed.

  As described above, according to the present embodiment, even if the occupation range of the irradiation area imaging range within the imaging range 1 of the left side camera 15 varies with the change in the steering angle of the handle 21, this variation occurs. Following this, the photometric area can be changed so that the image in the range used for generating the left side view image in the captured image of the left side camera 15 becomes an image captured under appropriate exposure.

  As a result, the brightness of the image used for generating the left side view image can be set to an appropriate brightness regardless of the night driving state of the vehicle equipped with the AFS, and as a result, the brightness of the overexposure etc. A good left side view image without any abnormality can be obtained.

  In addition, this invention is not limited to embodiment mentioned above, A various change is possible as needed.

  For example, in the above-described embodiment, the left side view image is cited as an example of the vehicle periphery monitoring image. However, the present invention is not limited to such a configuration. For example, as the vehicle periphery monitoring image, You may make it employ | adopt the right side view image etc. for monitoring the right front (front side) of the own vehicle produced | generated based on the captured image of the right side camera (not shown) attached to the right door mirror of the own vehicle. .

  The present invention is also applied to automatic exposure when capturing an image used for purposes other than the vehicle periphery monitoring image such as an image for notifying the traffic information center or the like of the situation near the accident site. be able to.

1 is a schematic diagram showing a vehicle periphery monitoring device provided with an in-vehicle camera automatic exposure device in an embodiment of an in-vehicle camera automatic exposure device according to the present invention. Block diagram showing the detailed configuration of FIG. In embodiment of the automatic exposure apparatus for vehicle-mounted cameras which concerns on this invention, (a) is explanatory drawing which shows the setting method of the photometry area | region in the straight running state of the own vehicle, (b) is the curve running state of the own vehicle It is explanatory drawing which shows the setting method of the photometry area | region in. The block diagram which shows the detailed structure of a left side camera in embodiment of the automatic exposure apparatus for vehicle-mounted cameras which concerns on this invention. In embodiment of the automatic exposure apparatus for vehicle-mounted cameras which concerns on this invention, (a) is explanatory drawing which shows the straight running state of the own vehicle in the lighting state of a headlamp, (b) is lighting of a headlamp. It is explanatory drawing which shows the curve driving | running | working (left curve driving | running | working) state of the own vehicle in a state. FIG. 3 is an explanatory view showing a left side view image corresponding to the photometric area of FIG. 3B in the embodiment of the on-vehicle camera automatic exposure device according to the present invention. Explanatory drawing which shows the setting state of the photometry area of the left side camera on the road at night by the center photometry Explanatory drawing which shows the left side view image corresponding to the photometry area | region of FIG. Explanatory diagram showing the setting state of the photometry area excluding the brightness of unnecessary objects Explanatory drawing which shows the capture state of the irradiation area | region within the imaging range of the left side camera by the influence of AFS Explanatory drawing which shows the problem caused by the capture state of the irradiation area | region within the imaging range of the left side camera by the influence of AFS shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging range 15 Left side camera 21 Handle 25 Left headlamp 31 Data storage part 36 AFS information acquisition part 37 Irradiation area imaging range estimation part 38 Photometric area setting part 40 Irradiation area imaging range 41 Photometric area

Claims (5)

A variable light distribution front that maintains the state in which the headlight light is irradiated in the traveling direction of the host vehicle by causing the steering direction of the headlamp of the host vehicle to follow the steering direction of the steering wheel of the host vehicle. It is installed in a host vehicle equipped with a lighting system,
An in-vehicle camera that images a predetermined area around the host vehicle;
As a photometric area used for automatic exposure of this in-vehicle camera, a photometric area setting means for setting a photometric area such that an image in a range used in an image captured by the in-vehicle camera is an image captured under appropriate exposure;
Steering angle / irradiation direction information acquisition means for acquiring at least one of information regarding the steering angle of the steering wheel and information regarding the irradiation direction of light of the headlamp corresponding to the steering angle of the steering wheel;
Based on the acquisition information of the steering angle / irradiation direction information acquisition means, the in-vehicle on the irradiation area imaging range which is a range used for imaging the area irradiated with the light of the headlamp in the imaging range of the in-vehicle camera. Irradiation area imaging range estimation means for estimating the occupation range within the imaging range of the camera, including the presence or absence of the irradiation area imaging range within the imaging range of the in-vehicle camera,
The in-vehicle camera, wherein the photometric area setting means is configured to be able to change the photometric area in accordance with a change in an estimation result of the irradiation area imaging range estimation means accompanying a change in a steering angle of the steering wheel. Automatic exposure device. The photometric area setting means is
The photometric area is formed such that a ratio of the area of the irradiation area imaging range included in the photometric area to the area of the entire photometric area is set to a predetermined threshold value or more. The automatic exposure apparatus for vehicle-mounted cameras of Claim 1.   The image of the range that is used is an image of a range that is used to generate a vehicle periphery monitoring image for monitoring a predetermined monitoring range around the host vehicle. The automatic exposure apparatus for vehicle-mounted cameras of Claim 2. The in-vehicle camera is a side camera attached to a side portion of the host vehicle,
The on-vehicle camera automatic exposure device according to claim 3, wherein the vehicle periphery monitoring image is a side view image for monitoring a front side of the host vehicle. The photometric area setting means is
When the estimation result corresponding to the straight traveling state of the host vehicle is obtained by the irradiation area imaging range estimation unit, the photometric area is used to capture an image of the used range in the imaging range of the in-vehicle camera. Set a photometric area with an area range that matches or approximates the range to be used,
When the estimation result corresponding to the curved traveling state of the host vehicle is obtained by the irradiation region imaging range estimation unit, the photometric region when the estimation result corresponding to the straight traveling state of the host vehicle is obtained. The in-vehicle camera automatic exposure device according to claim 4, wherein the photometric area shifted in the direction of the irradiation area imaging range is set.