JP2007223342A - Rear monitoring camera of vehicle and driving support device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving support device capable of maintaining sufficient accuracy for performing a three-dimensional distance measurement without damaging vehicle design. <P>SOLUTION: In the driving support device, the driving support is performed by using a rear monitoring camera of a vehicle composed by having a plurality of cameras, and image information taken by the rear monitoring camera. The plurality of cameras are fixed to a common one member, and are provided on the place which is in the range of the recessed part of a vehicle body wherein a license plate of the rear part of the vehicle is mounted through the member, and which is not projected with respect to the vehicle body. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an in-vehicle camera device mounted on a vehicle such as an automobile and a driving support device that supports driving using the on-vehicle camera device, and more particularly to a device that supports driving behind the vehicle.

  In recent years, when a vehicle is moving backward, such as turning around or parking in a parking lot, the situation behind the vehicle is photographed with an in-vehicle camera provided at the rear of the vehicle, and the blind spot from the driver behind the vehicle is provided by providing it to the driver. Vehicles equipped with a driving support device called a back view monitor that assists driving by reducing the number of vehicles are becoming popular. Recently, the driving support device has a function of supporting driving by not only displaying a rear image but also highlighting a parking lot line on the image or displaying a predicted course of a vehicle based on a steering angle. Has also been realized.

  For example, Japanese Patent Laid-Open No. 2002-321581 discloses a parking assistance device that displays an image of the traveling direction of a vehicle, predicts the course of the vehicle based on the steering angle, and avoids contact with an object such as a parked vehicle. Is disclosed. In such a driving support device, the determination of the actual parking location is performed by the driver in advance, whether there is an obstacle in the destination area or whether there is enough space for parking. Judgment was left to the driver.

  In contrast to such a conventional driving support device, for example, Japanese Patent Application Laid-Open No. 2003-2138 detects an obstacle using an image captured by a stereo camera including two cameras, and alerts the driver. Alternatively, a driving assistance device that performs a brake assist operation is disclosed.

JP 2002-321581 A JP 2003-2138 A

  Japanese Patent Application Laid-Open No. 2003-2138 discloses that two cameras constituting a stereo camera are installed on the body near the ceiling at both corners of the rear window. When the camera is provided at such a position, depending on the shape of the vehicle, the projection of the camera unit may significantly impair the vehicle design, and the optical axes of the two cameras are displaced from each other due to the distortion of the body. The accuracy of distance measurement may be reduced.

  Although the stereo camera is an expensive device, the use opportunity is limited when the vehicle is parked or retreated, and there is a problem that the operation rate is low and the stereo camera cannot be used effectively. Furthermore, in order to perform high-precision control, a high-resolution image sensor is required. However, the size of the pixel is proportional to the sensitivity. The three-dimensional distance measurement performance is degraded. An image pickup device having the same pixel size and a large optical size is very expensive, and there is a problem of cost as a vehicle-mounted component.

  In order to solve the above-described problem, the driving support device according to the present invention is a vehicle driving support device configured to include a plurality of cameras, and the plurality of cameras are fixed to a common member, It is a range of the recessed part of the vehicle body in which a vehicle rear number plate is attached, Comprising: It is provided in the place which does not protrude with respect to a vehicle body.

  Preferably, the plurality of light sources that illuminate the imaging range of the camera are fixed to the same member as the member to which the plurality of cameras are fixed. The plurality of light sources emit light having the same wavelength as the sensitivity wavelength of the image sensor included in the camera, and the amount of light is adjusted independently.

  A driving support device capable of maintaining sufficient accuracy to perform three-dimensional distance measurement without impairing the vehicle design can be realized.

  FIG. 1 is a schematic block diagram illustrating a configuration of a driving support apparatus according to an embodiment of the present invention.

The driving support device includes a rear monitoring stereo camera 10, a first light source 11, a second light source 12, a control unit 13, an accelerator control device 14, a steering control device 15, a brake control device 16, a vehicle speed sensor 17, and an R range detection. The means 18 includes a steering angle sensor 19, a navigation system 20, an active headrest device 21, and an air bag device 22.

  The control unit 13 may be connected to a front monitoring camera (not shown) that detects a white line or a vehicle.

  Each of these devices and means is connected to each other via communication means such as CAN.

  FIG. 2 is a block diagram showing the configuration of the rear monitoring stereo camera. The rear monitoring stereo camera 10 includes a first camera 110, a second camera 120, and a processing unit 130.

  The first camera 110 and the second camera 120 have the same configuration, and an optical system 111 configured by a lens or the like, and an image sensor 112 that converts an image obtained through the optical system 111 into an electrical signal, An AD converter 113 that converts an analog electrical signal obtained by the image sensor 112 into a digital signal is included. Although not shown, the optical system 111 includes a lens, a deflection filter, a visible light cut filter, and the like.

  For example, it is preferable to use a high-resolution image sensor 112 having a resolution of 380,000 pixels or more. By using a high-resolution image sensor, high-accuracy image processing can be performed, three-dimensional distance measurement accuracy can be improved, and a correction white balance provided for errors in the installation of the apparatus and optical axis misalignment due to changes over time. Can be increased.

  The AD converter 113 is an AD converter for an image sensor having a resolution of 10 bits or more, and has functions such as correlated double sampling (CDS), programmable gain control (PGA), and timing generator (TG). . If a CMOS sensor in which these functions are integrated on the image sensor 112 and one semiconductor chip is used, the device can be miniaturized.

  The processing unit 130 includes an image processing LSI 131, a CPU 132, a CAN driver 133, a memory 134, a first light source driving circuit 135, and a second light source driving circuit 146.

  The image processing LSI 131 is an LSI that takes in digital video output output from the first camera 110 and the second camera 120, performs processing such as extraction of video feature values, and three-dimensional distance measurement based on parallax of the two cameras. It is.

  The CPU 132 controls the shutters and gains of the first camera 110 and the second camera 120, and obtains information such as obstacles and approaching vehicles behind the vehicle obtained based on the result of image processing by the image processing LSI 131, CAN. The data is transferred to the host control unit 13 through communication means such as a driver 133 and a CAN bus. In addition, the light quantity restriction, on / off control, and the like for the first light source 11 and the second light source 12 are performed.

  The memory 134 stores a buffer and a program for temporarily storing image data. The image processing LSI 131, the CPU 132, the memory 134, and the like may be integrated into one chip by a multichip module or the like for miniaturization.

  The first light source drive circuit 135 and the second light source drive circuit 136 perform DUTY control and current control in order to control the on / off of the corresponding light source and the amount of light, respectively. The light emission wavelengths of the first light source drive circuit 135 and the second light source drive circuit 136 are based on the sensitivity characteristics of the image sensor 112, and have a peak of the light emission wavelength according to the wavelength at which the sensitivity of the image sensor is high. . As a result, it is possible to efficiently acquire video information in terms of light quantity, and it is possible to compensate for a decrease in sensitivity due to higher resolution of the image sensor 112.

  FIG. 3 is an external view of the stereo camera 10 according to the embodiment of the present invention.

  The stereo camera 10 includes a stay 201 and left and right camera mechanism units 202.

  The first camera 110 is disposed on one side of the left and right camera mechanism unit 202, and the second camera is disposed on the other side. The camera mechanism unit 202 is configured to maintain the positional relationship between the optical system 111 and the image sensor 112 of each of the first and second cameras.

  The stay 201 fixes the optical axes of the left and right camera mechanism sections 202 in an appropriate direction for measuring a three-dimensional distance. The stay 201 is made of a highly rigid material that is resistant to vibration and impact in order to maintain the accuracy of three-dimensional distance measurement.

  In addition to the camera mechanism 202, the first light source 11 and the second light source 12 are disposed on the left and right sides of the stay 201, respectively. That is, the first and second light sources 11 and 12 are provided in pairs on the left and right. The stay 201 is also used as a housing for fixing a printed circuit board on which a circuit that implements the processing unit 130 or the like is mounted.

  FIG. 4 is a partial external view of the vehicle showing the mounting position of the stereo camera 10.

  Many passenger cars have a license plate installed in the trunk at the rear of the vehicle or in a recess where a hatch door opener is provided. FIG. 4 shows a partial appearance of a so-called sedan type passenger car as viewed from the rear. A number plate 402 is attached to the recess 400 and a trunk opener 601 is provided.

  In the present embodiment, the rear monitoring stereo camera 10 is incorporated in the upper part of the license plate 402 of the recess 400 so as to be inside the trunk or hatch surface. By installing the rear monitoring stereo camera 10 in this way, the body line of the vehicle is not damaged, and it is possible to make it less susceptible to direct influences from rain, direct sunlight, dirt from mud splashes, and the like. At this time, adjustment is made so that at least a part of the bumper of the host vehicle is included in a part of the region photographed by the first and second camera devices 110 and 120.

  The first light source 11 provided in the rear monitoring stereo camera 10 mainly irradiates a long distance, and is controlled to be always lit at night in conjunction with a small light or the like. Moreover, it is comprised so that the emitted light may be guide | induced to the license plate 402 with a reflector etc., and a license plate is irradiated simultaneously with a distant place. If it is necessary to acquire a farther image at night, it is possible to control the first light source driving circuit 135 to adjust the light amount.

  The second light source 12 is configured as a light source that irradiates a wider angle range although it is a short distance than the first light source 11. The second light source 12 is turned on when the R range detecting means 18 detects that the shift lever is put in the reverse position (R range). The second light source 12 may not only illuminate a short distance, but may also be used as a back lamp.

  FIG. 5 is a flowchart showing a flow of processing performed by the control unit 13. When the ignition key is turned on, the control unit 13 is supplied with power and starts its processing.

  When activated, the control unit 13 first performs initialization processing such as clearing various setting values (step S100).

  After the initialization process, the control unit 13 captures an image from the rear monitoring stereo camera 10 and determines whether or not an object recognized as a bumper of the host vehicle by edge extraction, color determination, etc. is within a predetermined range. The rear monitoring stereo camera 10 is checked for abnormalities such as contamination of the camera lens and optical axis deviation. When an abnormality is detected in this determination, the control unit 13 determines whether or not the correction is possible by correction such as correction of the origin of image capture (steps S101 and S103). If it is determined that the video is not normal as a result of these determinations, the control unit 13 issues a warning indicating that the system operation is not possible to the driver (step S102).

  In step S104, the control unit 13 determines whether or not it has been confirmed by the R range detection means 18 that the shift lever position is set to the R range. If the shift lever is set to the R range, the navigation system 20 captures information near the current position of the host vehicle (step S105). It is determined from the information captured from the navigation system 20 whether there is a home or a parking lot near the current position of the host vehicle (step S106). If there is no home or parking lot near the current position of the host vehicle, the process returns to step S104. When a home or a parking lot exists near the current position of the host vehicle, the control unit 13 shifts to the parking driving support mode (step S107). When parking is finished, the parking driving support mode is finished, and the processing after S104 is continued.

  In the parking assistance mode, while using information obtained from the rear monitoring stereo camera 10, the vehicle speed sensor 17, the steering steering angle sensor 19, the accelerator control device 14, and the steering control device 15, the parking lot line highlight display, steering It provides assistance to the driver, such as displaying the predicted course of the vehicle based on the corners. A known technique can be applied to such driving assistance, and detailed description thereof is omitted here.

  In step S104, when the shift lever is not in the R range, the control unit 13 shifts the operation mode to the rear monitoring mode (step S108). In the rear monitoring mode, first, based on information from the rear monitoring stereo camera 10, it is determined whether there is an approaching vehicle from the rear (step S109). If an approaching vehicle from the rear is not detected, the process returns to step S104.

  When there is an approaching vehicle from behind and a collision is predicted, the control unit 13 controls the airbag device 22 and the active headrest device 21 to protect the occupant from the impact caused by the collision (steps S110 and 111).

  The determination of the approaching vehicle in step S109, the control of the airbag device 22 in step S110, and the control of the active headrest device 21 in step S111 are the rear monitoring stereo camera 10, the vehicle speed sensor 17, the steering steering angle sensor 19, and the accelerator control device 14. , Based on information from the steering control device 15, a known technique can be applied to these processes, and a detailed description thereof will be omitted here.

  6 and 7 are image diagrams for explaining a pixel range to be used.

  Assuming that the effective pixel range of the image sensor is X × Y, the X0 and Y0 regions located outside the broken line 610 of the image in FIG. 6 are corrections for correcting an optical axis shift due to an incorporation error or a change with time. Used as white.

  For functions such as parking assistance, a wide range of video information is required. For example, when the vehicle speed is a relatively slow vehicle operation of 10 km / h or less, all of the effective pixels X × Y to the X0 and Y0 areas are excluded. A region X1 × Y1 (a region surrounded by a broken line 610) is used. As information of a wide angle of view is processed, time is required for data transfer, video data processing, etc., but there is no particular problem in parking assistance with a relatively low vehicle speed.

  On the other hand, prediction of a vehicle collision approaching from behind requires processing in a shorter time, but can be sufficiently performed if there is video information in a relatively narrow range. For this reason, the video area to be used is limited to, for example, an area of X2 × Y2 (area surrounded by a broken line 620 in FIG. 7) to save time required for data transfer, video data processing, and the like. In the present embodiment, a wide range of video is used in the parking assistance mode, and the pixel range is switched so as to limit the video area to be used in the rear monitoring mode.

  According to the embodiment described above, the two cameras constituting the vehicle rear monitoring device are fixed to one common member and arranged on both sides of the trunk of the vehicle and the opener of the hatch door. In addition, it is provided in a place where it does not protrude from the vehicle body within the range of the recess having the rear number plate. Thereby, it can prevent impairing the design of a vehicle.

  In addition, it is possible to adjust the amount of light for each light source, and since multiple light sources whose wavelengths of emitted light are substantially the same as the sensitivity wavelength of the image sensor are used, video is acquired at high resolution even at night. It is possible to realize a high-performance backward driving support device that can perform at a low cost.

  In addition, the monitoring function and parking support function for vehicles approaching from the back can be realized with a single device, and since the rear monitoring camera is used not only during back travel but also during normal travel, more expensive cameras can be used more effectively. be able to.

It is a schematic block diagram which shows the structure of the driving assistance device in one Embodiment of this invention. It is a block diagram which shows the structure of the stereo camera for back monitoring. 1 is an external view of a stereo camera 10 for rear monitoring. 1 is a partial external view of a vehicle showing a mounting position of a rear monitoring stereo camera 10; FIG. 4 is a flowchart showing a flow of processing performed by a control unit 13. It is an image figure for demonstrating the pixel range used. It is an image figure for demonstrating the pixel range used.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Stereo camera for back monitoring, 11 ... 1st light source, 12 ... 2nd light source, 13 ... Control unit, 14 ... Accelerator control apparatus, 15 ... Steering control apparatus, 16 ... Brake control apparatus, 17 ... Vehicle speed sensor, DESCRIPTION OF SYMBOLS 18 ... R range detection means, 19 ... Steering steering angle sensor, 20 ... Navigation system, 21 ... Active headrest apparatus, 22 ... Air bag apparatus, 110 ... First camera, 111 ... Optical system, 112 ... Imaging element, 113 ...
AD converter, 120 ... second camera, 130 ... processing unit, 131 ... image processing LSI, 132 ... CPU, 133 ... CAN driver, 134 ... memory, 135 ... first light source driving circuit,
136: second light source driving circuit, 201: stay, 202 ... camera mechanism, 401 ... rear door opener, 402 ... license plate.

Claims (8)

In a driving support device having a vehicle rear monitoring camera including a plurality of cameras and a control device that performs driving support using video information captured by the rear monitoring camera,
The plurality of cameras are fixed to a common member, and are provided in a region of a concave portion of the vehicle body to which a license plate at the rear of the vehicle is attached via the member, and does not protrude from the vehicle body. A driving assistance device characterized by   The driving support apparatus according to claim 1, further comprising a light source that is fixed to the member and illuminates an area photographed by the plurality of cameras.   The driving support device according to claim 2, wherein a plurality of the light sources are provided.   The driving support apparatus according to claim 3, further comprising a light source driving circuit that independently adjusts the light amount of each of the plurality of light sources.   5. The driving support apparatus according to claim 2, wherein a wavelength of light emitted from the light source is the same as a sensitivity wavelength of an image sensor included in the plurality of cameras.   6. The driving support device according to claim 2, wherein the light source is controlled to be lit when the shift lever is set to the R range.   The driving support device according to claim 2, wherein the light source is controlled to be turned on / off in conjunction with a small light switch. The driving support device according to claim 2, wherein the control device switches the number of pixels of an image captured by the plurality of cameras according to a set position of a shift lever.

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