JP2007334760A - Drive recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive recorder which will not decide to start recording that uses an acceleration sensor so that the recording of images do not start erroneously, even when a vehicle travels on a road having many irregulaties or on a rail road crossing, and when the vehicle oscillates. <P>SOLUTION: A plurality of cameras 5-8 are mounted on a vehicle, and the periphery of the vehicle is photographed extending to 360°; distance up to an object in the periphery of the vehicle is computed, based on the images which are picked up with the cameras 5-8; and the distance to the object in the periphery of the vehicle is also acquired with a plurality of sonars 10-14. When the distance up to the object in the periphery of the vehicle becomes smaller than a prescribed distance, the images picked up with the camera 5-8 are recorded to a nonvolatile memory 24. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drive recorder that can capture an image of the periphery of a vehicle using a camera mounted on the vehicle and record an image captured by the camera when the vehicle collides.

  Conventionally, a drive recorder capable of recording various data of a vehicle at the time of a vehicle collision has been put into practical use. The drive recorder records various data of the vehicle in a predetermined time of several seconds to several tens of seconds before and after the time when the collision occurs. The data to be recorded includes, for example, the collision time, the vehicle speed at the time of the collision, the acceleration, the operation angle of the steering wheel, the depression amount of the accelerator pedal, the operation of the brake, the operation of the direction indicator, or the light on / off. In addition, when a camera for imaging the periphery of the vehicle is mounted on the vehicle, there are some that can record an image captured by the camera. By recording these data by the drive recorder, there is an advantage that when a traffic accident occurs, the cause of the accident can be determined more accurately.

  In Patent Document 1, any of the presence / absence of the operation of an ABS (Anti-lock Break System) or the sudden steering of the steering wheel, the presence / absence of contact of the vehicle and other objects by the touch sensor, and the presence / absence of the collision by the high G sensor. There has been proposed a vehicle data recording device that records vehicle data for a predetermined period when it is detected. This vehicle data recording device eliminates useless recording by keeping the vehicle data recording period different according to the type of the recording start factor, and reliably holds the desired recording in a small memory capacity. can do.

In Patent Literature 2, the collected traveling by detecting the vibration state of the vehicle and starting and ending the backup of the data related to the traveling state from the nonvolatile memory to the mass storage medium according to the detected vibration state. An in-vehicle electronic device and a drive data recording method that can reliably back up data relating to a situation have been proposed.
JP 7-277230 A JP 2004-139204 A

  In the conventional drive recorder, an acceleration sensor is mounted in a device or a vehicle, and the acceleration detected by the acceleration sensor is often used as a trigger for starting recording of vehicle data. However, when the vehicle travels on a rough road surface or railroad crossings, the vehicle vibrates and the acceleration sensor detects acceleration, which may cause the drive recorder to malfunction. When this malfunction occurs, there is a problem that the vehicle data is recorded in a recording means such as a non-volatile memory or a hard disk mounted on the drive recorder, and the recording capacity of the recording means decreases due to unnecessary data.

  The vehicle data recording device described in Patent Document 1 is configured to detect the presence or absence of a collision between the vehicle and other objects by the high G sensor and start recording the vehicle data according to the detection result. have. Moreover, since the vehicle-mounted electronic device and the drive data recording method described in Patent Document 2 are configured to detect the vibration state of the vehicle and back up data related to the driving state from the nonvolatile memory to the large-capacity storage medium. Has similar problems.

  The present invention has been made in view of such circumstances, and an object of the present invention is to mount an imaging unit such as a camera on a vehicle and calculate a distance to an object captured in the captured image. Then, when the calculated distance is closer than the predetermined distance, recording of the image without using an acceleration sensor is started by recording the image captured by the imaging unit on a recording unit such as a nonvolatile memory or a hard disk. An object of the present invention is to provide a drive recorder.

  Another object of the present invention is to temporarily store the image captured by the imaging unit and record the stored image on the recording unit when the distance to the object is shorter than a predetermined distance. Thus, an object of the present invention is to provide a drive recorder that can record an image before a vehicle collision.

  In addition, another object of the present invention is to provide a configuration in which an image captured at a predetermined time before and after the time when it is determined that the distance to the object is closer than the predetermined distance is recorded in the recording unit. An object of the present invention is to provide a drive recorder capable of reliably recording images before and after a vehicle collision necessary for investigating the cause of the vehicle.

  Another object of the present invention is that the distance to the object is based on the imaging position of the same object in a plurality of images captured by the imaging means after a certain period of time and the moving distance of the vehicle. Is to provide a drive recorder capable of calculating the distance to the object with a single imaging means.

  Another object of the present invention is to image the same object from different positions with a plurality of imaging means, and the imaging positions of the same object in the images respectively captured by the plurality of imaging means, By calculating the distance to the object based on the distance between the imaging means, the distance to the object can be reliably calculated even when the vehicle is not moving. It is to provide a drive recorder.

  Another object of the present invention is to arrange the imaging means on the front side, the rear side, and the left and right sides of the vehicle so that the imaging is performed over 360 ° in the horizontal direction of the vehicle. It is an object of the present invention to provide a drive recorder capable of reliably recording a captured image even when a collision occurs in any of the above locations.

  Another object of the present invention is to detect the distance to the object using sonar, and to record the image on the recording means when the distance to the object is shorter than a predetermined distance. It is to provide a drive recorder that can record an image more reliably by using both of them.

  A drive recorder according to a first aspect of the present invention is a drive recorder that is mounted on a vehicle and includes an imaging unit that images the periphery of the vehicle, and a recording unit that records an image captured by the imaging unit. A calculation unit that calculates a distance to the object captured in the image; and a determination unit that determines whether or not the distance calculated by the calculation unit is shorter than a predetermined distance, and the distance to the target is a predetermined distance The recording means records the image picked up by the image pickup means when the determination means determines that the distance is closer.

  In the present invention, an imaging unit such as a camera is mounted on the vehicle, the distance from the image captured by the imaging unit to the object is calculated, and when the distance to the object is closer than a predetermined distance, the captured image is It records in recording means, such as a non-volatile memory or a hard disk. When the distance to the object is shorter than the predetermined distance, the possibility that the vehicle will collide with the object is high. Therefore, the distance to the object can be used as a trigger for starting image recording. Since image recording can be started only from the distance to the object, it is not necessary to mount an acceleration sensor, and malfunctions can be reduced. Further, recording can be started before the vehicle collides with the object.

  The drive recorder according to the second aspect of the invention comprises storage means for temporarily storing images picked up by the image pickup means, and when the determination means determines that the distance to the object is closer than a predetermined distance, An image stored by the storage unit is provided to the recording unit, and the recording unit records an image captured by the imaging unit supplied from the storage unit.

  In the present invention, the image picked up by the image pickup means is temporarily stored, and when the distance to the object is shorter than a predetermined distance, the stored image is recorded in the recording means. By accumulating the captured images for a certain period, when a vehicle collision occurs, the image before the collision can be recorded in the recording means.

  In the drive recorder according to the third aspect of the invention, the recording unit records images taken at a predetermined time before and after the determination unit determines that the distance to the object is closer than a predetermined distance. It is characterized by being.

  In the present invention, when it is determined that the distance to the object is shorter than the predetermined distance, images captured within a predetermined time before and after this point are recorded in the recording means. Since the images before and after the collision of the vehicle are useful for investigating the cause of the collision, the images within this time are recorded reliably.

  In the drive recorder according to the fourth aspect of the invention, the calculation unit may determine the imaging position of the same object in a plurality of images captured by the imaging unit at different time points, and the moving distance of the vehicle between the different time points. Based on the above, the distance to the object is calculated.

  In the present invention, the distance to the object is based on the imaging position of the same object captured in a plurality of images captured by the imaging means at a certain time and the distance the vehicle has moved within the certain time. Is calculated. The distance traveled by the vehicle is detected using a wheel speed sensor or the like. Thereby, the distance to a target object can be acquired with one imaging means, and the number of imaging means mounted on the vehicle can be reduced.

  In the drive recorder according to the fifth aspect of the present invention, a plurality of the image pickup means are provided and arranged in the vehicle at a predetermined distance, and the plurality of image pickup means can pick up the same object from different positions. The calculating means calculates the distance to the object based on the imaging position of the same object in the images captured by the plurality of imaging means and the predetermined distance. It is characterized by being.

  In the present invention, a plurality of imaging means images the same object from different positions. The distance to the object is calculated based on the imaging position of the same object captured in the images captured by the plurality of imaging means and the distance between the imaging means. When calculating the distance from an image captured by a single imaging means, it is necessary to obtain the amount of movement of the vehicle, but when calculating the distance from images captured by a plurality of imaging means, the amount of movement of the vehicle is required. Therefore, the distance can be easily and reliably calculated even when the vehicle is stopped.

  In the drive recorder according to the sixth aspect of the present invention, the imaging means is disposed on the front side, the rear side, and the left and right sides of the vehicle, respectively, and images the periphery of the vehicle in the horizontal direction over 360 °. It is characterized by being.

  In the present invention, imaging means are disposed on the front side, the rear side, and the left and right sides of the vehicle, respectively. By using all the imaging means, the image of the periphery of the vehicle in the horizontal direction is taken over 360 °. Since a vehicle collision may occur on the front side, the rear side, or the left and right sides of the vehicle, it is possible to more reliably investigate the cause of the collision by imaging the surrounding area over 360 ° and recording this image. It can be performed.

  Further, a drive recorder according to a seventh aspect of the present invention includes a detection unit that detects a distance to an object using sonar, and a determination unit that determines whether the distance detected by the detection unit is closer than a predetermined distance, When the determination unit determines that the distance to the object is closer than a predetermined distance, the recording unit records an image captured by the imaging unit.

  In the present invention, the drive recorder further includes a sonar. The distance to the object is detected by the sonar, and when the distance to the object is closer than the predetermined distance, the image captured by the imaging unit is recorded in the recording unit. By using both the calculation of the distance to the object based on the image captured by the imaging means and the detection of the distance to the object by sonar, the distance to the object can be obtained more reliably, Images can be recorded more reliably.

  In the case of the first invention, the image pickup means is mounted on the vehicle, the distance to the object shown in the image picked up by the image pickup means is calculated, and the image pickup means picks up the image when the calculated distance is closer than the predetermined distance. With the configuration in which the image is recorded in the recording unit, it is possible to determine the start of image recording without using an acceleration sensor, so that a malfunction due to erroneous determination of the acceleration sensor does not occur. In addition, since the image recording can be started before the vehicle collides with the object, the image recording can be performed more reliably. Therefore, the reliability of the drive recorder can be improved.

  According to the second aspect of the invention, the image picked up by the image pickup means is temporarily stored, and when the distance to the object is closer than a predetermined distance, the stored image is recorded in the recording means. When a vehicle collision occurs, the image before the collision can be recorded in the recording means, so that the cause of the vehicle collision can be surely determined based on the image, and the drive recorder can be effectively used. Can be used.

  Further, in the case of the third invention, the cause of the collision is investigated by configuring the recording means to record images taken within a predetermined time before and after the time point when it is determined that the distance to the object is closer than the predetermined distance. It is possible to reliably record images before and after a vehicle collision that is useful for the vehicle, so that it is possible to more reliably investigate the cause of a vehicle collision based on the image, and to use the drive recorder more effectively. it can.

  Further, in the case of the fourth invention, the distance to the object is calculated based on the imaging position of the same object in a plurality of images taken by the imaging means after a certain period of time and the moving distance of the vehicle. By adopting the configuration, the distance to the object can be acquired with one image pickup means, and the number of image pickup means mounted on the vehicle can be reduced. Therefore, the distance to the object based on the image picked up by the image pickup means It is possible to suppress an increase in the cost of the drive recorder by installing a function for calculating the.

  Further, in the case of the fifth invention, the same object is imaged from different positions by the plurality of imaging means, and the imaging position of the same object in the images respectively captured by the plurality of imaging means, and the plurality of imaging means By calculating the distance to the object based on the distance between the two, the distance to the object can be calculated easily and reliably even when the vehicle is stopped. The accuracy of the recorder can be increased and the reliability of the drive recorder can be increased.

  In the case of the sixth invention, the image pickup means is arranged on the front side, the rear side, and the left and right sides of the vehicle, and is configured to take an image over 360 ° in the horizontal direction of the vehicle. Even when a collision occurs at a location, the captured image can be reliably recorded, so that the cause of the vehicle collision can be reliably determined based on the image, and the drive recorder can be effectively Can be used.

  According to the seventh aspect of the invention, the image pickup means picks up the image by detecting the distance to the object using sonar and recording the image on the recording means when the distance to the object is closer than the predetermined distance. The reliability of the drive recorder can be improved because the calculation of the distance to the object based on the captured image and the detection of the distance to the object by sonar can be used together to record the image more reliably. Can do.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. FIG. 1 is a schematic plan view showing a configuration of a vehicle equipped with a drive recorder according to the present invention. In the figure, reference numeral 1 denotes a vehicle. The vehicle 1 is equipped with four cameras 5 to 8 for imaging the periphery, and five sonars (SONAR: Sound Navigation And Ranging) for detecting obstacles existing in the vicinity. 10-14 are installed. In FIG. 1, (a) illustrates the imaging range of the cameras 5 to 8 as a region surrounded by a broken line, and (b) illustrates the obstacle detection range of the sonars 10 to 14 as a region surrounded by a broken line. It is shown.

  A camera 5 that captures the front is mounted on the front of the vehicle 1, and a camera 6 that captures the rear is mounted on the rear. The left and right door mirrors of the vehicle 1 are equipped with cameras 7 and 8 that image the left and right sides of the vehicle 1. The cameras 5 to 8 are cameras having an angle of view of 180 ° or more, and by mounting the four cameras 5 to 8 on the four sides of the vehicle 1, the horizontal periphery of the vehicle 1 extends over 360 °. An image can be taken. By using these cameras 5 to 8, for example, the captured image is displayed on a display disposed in the vicinity of the driver's seat of the vehicle 1, and the driver indirectly visually observes a blind spot around the vehicle 1. Driving.

  A sonar 10 for detecting an obstacle ahead of the vehicle 1 is mounted on the front portion of the vehicle 1. By using the sonar 10, for example, it is possible to perform control such as measuring the distance between the vehicle and another vehicle traveling ahead, giving a warning to the driver, or automatically adjusting the traveling speed of the vehicle 1. In addition, sonars 11 and 12 for detecting obstacles in front of the left and right sides of the vehicle 1 are mounted on the left and right front corners of the vehicle 1, respectively. Similarly, sonars 13 and 14 for detecting obstacles on the left and right rear sides of the vehicle 1 are mounted on the left and right corners of the vehicle 1, respectively. By using the sonars 11 to 14, for example, when the vehicle 1 travels on a narrow road, enters a garage, or performs parallel parking, the driver is informed of the presence or absence of obstacles around the vehicle 1. I can inform you.

  The vehicle 1 is equipped with a drive recorder that records images captured by the cameras 5 to 8 for several seconds to several tens of seconds before and after the collision when a collision accident occurs. The cameras 5 to 8 and the sonars 10 to 14 mounted on the vehicle 1 can be used for the purpose of assisting the driver as described above and constitute components of the drive recorder. FIG. 2 is a block diagram showing the configuration of the drive recorder according to the present invention.

  The drive recorder mounted on the vehicle 1 detects a collision of the vehicle 1 based on the imaging unit 9 having the cameras 5 to 8, the ultrasonic detection unit 19 having the sonars 10 to 14, and data given from these. And a control unit 20 that performs processing for recording the image captured by the imaging unit 9.

  The cameras 5 to 8 of the imaging unit 9 each have an imaging element in which image sensors by CCD or CMOS are arranged in a matrix, and one or a plurality of lenses for condensing light on the imaging element. It is an apparatus that performs imaging at a frequency of about 30 times per second by detecting light collected by a lens by an image sensor of an imaging device. As the lenses of the cameras 5 to 8, lenses having a wide angle of view such as wide-angle lenses or fish-eye lenses are used. The imaging unit 9 is connected to an I / F (interface) unit 25 of the control unit 20, and gives an image around the vehicle 1 captured by the imaging elements of the cameras 5 to 8 from the I / F unit 25 to the control unit 20. It is like that.

  The sonars 10 to 14 of the ultrasonic detection unit 19 emit ultrasonic waves in a predetermined direction of the vehicle 1, and detect reflected waves reflected by obstacles existing in the ultrasonic emission direction, thereby detecting each of the sonars. It is a device that obtains the distance to an obstacle and is a so-called active sonar. The ultrasonic detection unit 19 is connected to the I / F unit 26 of the control unit 20, and gives the control unit 20 the presence / absence of the obstacle and the distance to the obstacle acquired by the sonars 10 to 14. .

  The control unit 20 temporarily stores an image captured by the CPU 21 that performs processing such as calculation and control, a ROM 22 that stores programs and data executed by the CPU 21, and the cameras 5 to 8 of the imaging unit 9. A volatile memory 23 stored in the vehicle, a non-volatile memory 24 for recording an image when a collision of the vehicle 1 occurs, an I / F unit 25 to which the imaging unit 9 is connected, and an I / F to which the ultrasonic detection unit 19 is connected. The F unit 26 is connected to each other via a bus 27 so that data can be exchanged between them.

  The volatile memory 23 is a memory constituted by SRAM, DRAM, or the like, and images taken by the cameras 5 to 8 are sequentially given from the imaging unit 9 and the given images are accumulated for a predetermined time. In this case, an image that has passed a predetermined time is overwritten with a newly provided image. The volatile memory 23 is characterized in that the stored image is lost when the power supply is cut off, but the capacity is large and the image can be stored at high speed.

  The non-volatile memory 24 is a memory composed of a flash memory or the like, and can retain recorded data even when the power supply is cut off. It is small and has a feature that data recording is slow. The non-volatile memory 24 is provided with an image accumulated from the volatile memory 23 when a collision of the vehicle 1 occurs, and records the given image. Thereby, even when the vehicle 1 breaks down due to a collision and the power supply to the drive recorder is cut off, the image captured by the imaging unit 9 is not lost, and is used for investigating the cause of the collision. be able to.

  The ROM 22 is configured by a mask ROM, EEPROM, flash memory, or the like, and stores in advance a program executed by the CPU 21 and various data necessary for execution. The CPU 21 controls the operation of each part of the drive recorder by reading and executing the program stored in the ROM 22. The CPU 21 controls the above-described processing for backing up an image from the volatile memory 23 to the non-volatile memory 24, and whether or not to perform the backup is calculated based on the image captured by the imaging unit 9. The distance to the object around the vehicle 1 and the distance to the object around the vehicle 1 obtained by the ultrasonic detector 19 are set.

  FIG. 3 is a schematic diagram for explaining a distance calculation method performed by the drive recorder according to the present invention. In the following, the case of the camera 5 mounted on the front portion of the vehicle 1 will be described, but the same applies to the cases of the other cameras 6 to 8. In FIG. 3, the installation position of the camera 5 is the origin O, the optical axis direction of the camera 5 and the traveling direction of the vehicle 1 is the z direction, the left and right direction of the vehicle 1 is the x direction, and the vertical direction of the vehicle 1 is y. A directional xyz coordinate system is shown. When the focal length of the camera 5 is f, a uv coordinate system (hereinafter referred to as an image plane coordinate system) is provided at a position away from the origin O in the z direction in the z direction, and the u axis of the image plane coordinate system is The x axis is parallel, the v axis is parallel to the y axis, and the intersection with the z axis is the origin O ′ of the image plane coordinate system.

Point T object in _n positions the point D _n of (a stationary object to) (x _n, y _n, z _n) and, when T point the position of the object in the _{n + 1 D n + 1 (} x n + ₁ , y _{n + 1} , z _{n + 1} ). The image point of the object at time T _n is P _n (u _n , v _n ), and the image point of the object at time T _{n + 1} is P _{n + 1} (u _{n + 1} , v _{n + 1} ). . Further, the distance traveled by the vehicle 1 from the time point _Tn to the time point _{Tn + 1} , that is, the distance between the point Dn and the point Dn _{+ 1 in} the z direction is _denoted by ΔD.

Furthermore, if the intersection of the perpendicular line drawn from the point D _n to the xy plane and the xy plane is a point G, the point D _{n + 1} exists on the line segment D _n G. Further, if the intersection point of the perpendicular line segment D _n G drawn from the origin O ′ to the line segment D _n G is F, the image points P _n and P _{n + 1} exist on the line segment O′F. Further, an angle formed by the line segment OD _n and the z axis is θ, and an angle formed by the line segment OG and the x axis is φ. Further, the length of the line segment OD _n is r, and the length of the line segment OP _n is | P |.

Under the above conditions, the length | P _n F | of the line segment P _n F can be obtained as follows.

Similarly, the length | P _{n + 1} F | of the line segment P _{n + 1} F can be obtained as follows.

Assuming that the distance between the image point P _n and the image point P _{n + 1} is Δd, from the expressions (1) and (2), Δd is as follows.

The coordinates of the point D _n are expressed using r, θ, and φ as follows.
(X _n , y _n , z _n ) = (r cos φ sin θ, r sin φ sin θ, r cos θ) (4)
Further, the coordinates of the point D _n are expressed using u _n and v _n as follows.

  By comparing the z components of the equations (4) and (5), the following equation (6) can be derived.

(3) from the equation, and (6), when determining the length r of the line segment OD _n, as follows.

  Further, the following expressions (8) and (9) are established.

Therefore, from the equations (5), (7), (8), and (9), the coordinates (x _n , y _n , z _n ) of the point D _n are expressed as in the following equation (10). Can do.

(10) from the equation, the moving distance ΔD the vehicle, and the focal length f of the camera 5, and a image point P _n and P _{n + 1} in the coordinates of the image plane coordinate system, the position of the object at time T _n It can be seen that the coordinates of the point D _n can be calculated. The travel distance ΔD of the vehicle can be detected based on the wheel speed obtained from a wheel speed sensor (not shown) mounted on the vehicle.

FIG. 4 is a schematic diagram for explaining a method of acquiring the coordinates of the image points P _n and P _{n + 1 in} the image plane coordinate system. FIG. 4A illustrates an image 51 captured by the camera 5. (B) illustrates the image plane coordinate system. The image 51 captured by the camera 5 has a st coordinate system (hereinafter referred to as an image coordinate system) in which the upper left is the origin O ″, the horizontal direction is the s axis, and the vertical direction is the t axis.

The offset amount of the s-axis with respect to the optical axis is L1, and the offset amount of the t-axis with respect to the optical axis is L2. The length of the image 51 in the s-axis direction is W, and the length in the t-axis direction is H. The imaging position of the target object at the time point T _n is set as a point Q _n (s _n , t _n ), and the imaging position of the target object at the time point T _{n + 1} is set as a point Q _{n + 1} (s _{n + 1} , t _{n + 1} ). And In addition, the length in the u-axis direction of the image plane 52 in the image plane coordinate system corresponding to the image 51 captured by the camera 5 is w, and the length in the v-axis direction is h. At this time, the image point P _n (u _n , v _n ) in the image plane coordinate system can be expressed by the following equations (11) and (12). Note that the image point P _{n + 1} (u _{n + 1} , v _{n + 1} ) is a similar expression and will not be described.

By extracting the coordinates of the same object from the two images captured by the camera 5 at the time T _n and the time T _{n + 1 according} to the above expressions (10) to (12), the coordinates of the object, The distance from the camera 5 to the object can be calculated.

  The drive recorder according to the present embodiment calculates the distances from the images captured by the cameras 5 to 8 of the imaging unit 9 to the object captured in each image. In addition, the distance to the object can be acquired by the sonars 10 to 14 of the ultrasonic detector 19. In the drive recorder according to the present embodiment, the distance to the target obtained from either the cameras 5 to 8 of the imaging unit 9 or the sonars 10 to 14 of the ultrasonic detection unit 19 is a predetermined value. When the distance is shorter than the distance (for example, several centimeters to several tens of centimeters), the collision between the object and the vehicle 1 is expected, so the images captured by the cameras 5 to 8 of the imaging unit 9 and stored in the volatile memory 23 Is recorded in the nonvolatile memory 24. At this time, a predetermined time before and after the time when it is determined that the distance to the object is approached, for example, an image of a total of 20 seconds from 10 seconds before to 10 seconds after the determination time is recorded in the nonvolatile memory 24. . The non-volatile memory 24 has a capacity capable of recording, for example, 10 times = 200 seconds of images when images of several times to several tens of times, that is, images of 20 seconds at a time are recorded. When the image is continuously recorded and reaches the capacity, and further recording is performed, the oldest image is overwritten and recorded.

  FIG. 5 is a flowchart showing the procedure of the image recording process performed by the CPU 21 of the control unit 20 of the drive recorder according to the present invention. First, the CPU 21 checks the recording state of the nonvolatile memory 24 and acquires the recording start address of the nonvolatile memory 24 when recording is performed next time (step S1). The recording start address is the head address of the area when an unused area is left in the nonvolatile memory 24, and the area where the oldest image is recorded when the unused area is not left. Is the first address of.

  After acquiring the recording start address, the detection result of the vicinity of the vehicle 1 by the sonars 10 to 14 of the ultrasonic detection unit 19 is acquired (step S2), and whether or not the distance to the obstacle around the vehicle 1 is equal to or less than a predetermined distance. (Step S3). When the distance to the obstacle is not less than the predetermined distance (S3: NO), the surroundings of the vehicle 1 are imaged by the cameras 5 to 8 of the imaging unit 9 (step S4), and the captured images are stored in the volatile memory 23. (Step S5). Next, the image captured and accumulated last time is read from the volatile memory 23 (step S6), and the distance to the object is calculated by the above-described equations (10) to (12) (step S7). It is checked whether or not the distance to the object is equal to or less than a predetermined distance (step S8).

  When the distance to the obstacle based on the detection result of the ultrasonic detection unit 19 is equal to or smaller than the predetermined distance in step S3 (S3: YES), or to the object calculated from the image captured by the imaging unit 9 in step S8. When the distance is equal to or smaller than the predetermined distance (S8: YES), all the images captured before the predetermined time are read out from the images accumulated in the volatile memory 23 (step S9), and the read images are nonvolatile. All the data is recorded in the memory 24 (step S10), and thereafter, the image captured by the imaging unit 9 is recorded in the nonvolatile memory 24 for a predetermined time (step S11). Thereafter, the process returns to step S1, the recording start address for recording the image next time is acquired, and the above-described processing is repeated.

  In step S8, if the distance from the image captured by the imaging unit 9 to the calculated object is not equal to or smaller than the predetermined distance (S8: NO), it is checked whether an instruction to end the recording process is given (step S12). The end instruction is given to the CPU 21 when, for example, the engine of the vehicle 1 is stopped or when the user operates the operation stop switch of the drive recorder. If the end instruction has not been given (S12: NO), the process returns to step S2, and the above-described processing is repeated. If the end instruction has been given (S12: YES), the process ends.

  In the drive recorder having the above configuration, the distance to the object around the vehicle 1 is acquired using the cameras 5 to 8 of the imaging unit 9 and the sonars 10 to 14 of the ultrasonic detection unit 19, and according to this distance. By configuring the image to be recorded in the non-volatile memory 24, it is not necessary to mount an acceleration sensor on the drive recorder, so that the drive recorder may malfunction when the vehicle 1 travels on a rough road surface or railroad crossing. Absent. In addition, by adopting a configuration that records images of a predetermined time before and after the time point when it is determined that the distance to the object is equal to or less than the predetermined distance, the collision of the vehicle 1 is determined based on the images before and after the collision. The cause investigation can be performed reliably. In addition, by adopting a configuration in which images are taken over 360 ° in the horizontal direction of the vehicle 1 by the cameras 5 to 8, an image can be reliably obtained even when a collision occurs in any place around the vehicle 1. Can be recorded. In addition, it is possible to record an image more reliably by adopting a configuration in which the distance to the object is acquired by the two types of means of the cameras 5 to 8 of the imaging unit 9 and the sonars 10 to 14 of the ultrasonic detection unit 19. it can.

  In the present embodiment, the drive recorder has a configuration in which four cameras 5 to 8 are mounted. However, the present invention is not limited to this, and three or less cameras or five or more cameras may be mounted. However, it is desirable that the surroundings of the vehicle 1 can be imaged over 360 °. The positions where the cameras 5 to 8 are mounted on the vehicle 1, the imaging range, and the like are examples, and are not limited thereto. Similarly, the drive recorder has a configuration in which five sonars 10 to 14 are mounted. However, the present invention is not limited to this, and four or less or six or more sonars may be mounted, and further, no sonar is mounted. It may be a configuration. Further, the mounting positions and detection ranges of the sonars 10 to 14 are examples, and are not limited thereto.

  In addition, the image captured by the image capturing unit 9 is always stored in the volatile memory 23, and the image is recorded in the nonvolatile memory 24 when the distance to the object is equal to or less than the predetermined distance. For example, the imaging unit 9 may capture the image only when the distance to the object is equal to or less than a predetermined distance and record the image in the nonvolatile memory 24. The captured image is always recorded in the non-volatile memory 24, and the recording is stopped when the distance to the object is equal to or less than a predetermined distance, and the recording is not performed thereafter.

  Further, the nonvolatile memory 24 may be a memory other than a flash memory, for example, an MRAM or an FRAM. Furthermore, instead of the configuration in which the image is recorded in the non-volatile memory, a configuration in which the image is recorded in, for example, a hard disk may be employed.

(Modification)
FIG. 6 is a block diagram showing a configuration of a drive recorder according to a modification of the present invention. The imaging unit 109 of the drive recorder according to the modification includes eight cameras 5R, 5L, 6R, 6L, 7R, 7L, 8R, and 8L. Although illustration is omitted, the cameras 5R and 5L are mounted at a predetermined distance on the front portion of the vehicle 1 and both are configured to image the front of the vehicle 1. Similarly, the cameras 6 </ b> R and 6 </ b> L are mounted at a predetermined distance on the rear part of the vehicle 1, and both are configured to image the rear of the vehicle 1. The cameras 7 </ b> R and 7 </ b> L are mounted on the left part of the vehicle 1 with a predetermined distance, and both are configured to image the left side of the vehicle 1. The cameras 8 </ b> R and 8 </ b> L are mounted on the right part of the vehicle 1 with a predetermined distance, and both are configured to image the right side of the vehicle 1. In this way, one camera is imaged in two directions, and the periphery of the vehicle 1 in the horizontal direction is imaged over 360 °.

  FIG. 7 is a schematic diagram for explaining a distance calculation method performed by the drive recorder according to the modification of the present invention. In the following, the case of the cameras 5R and 5L mounted on the front portion of the vehicle 1 will be described, but the same applies to the case of other cameras. The CPU 121 of the control unit 120 of the drive recorder according to the modified example is different in the imaging position where the same object imaged simultaneously by the two cameras 5R and 5L appears on the images obtained by the respective cameras, that is, parallax. Accordingly, the distance to the object is calculated, and so-called stereo side distance calculation is performed.

The two cameras 5R and 5L are separated from each other at the front of the vehicle 1 by a predetermined distance b so that their imaging directions, that is, the optical axes are substantially parallel and the distances from the road surface are substantially equal. It is installed. In FIG. 7, the arrangement position of the camera 5R is the origin O, the imaging direction of the camera 5R is the z direction, the direction from the camera 5L to the camera 5R is the x direction, and the direction perpendicular to the z direction and the x direction is y. In the case of the direction, the position of the object D with respect to the origin O is represented by (x _d , y _d , z _d ). The cameras 5R and 5L are mounted on the vehicle 1 so that the z direction and the x direction are orthogonal to each other.

Further, when the focal length of the cameras 5R and 5L is f, a u ₁ v ₁ coordinate system (hereinafter referred to as the right image plane) is located at a position away from the installation position (origin O) of the camera 5R in the z direction. Coordinate system), the u ₁ axis of the right image plane coordinate system is parallel to the x axis, the v ₁ axis is parallel to the y axis, and the intersection with the z axis is the origin O ₁ of the right image plane coordinate system. . Similarly, a u ₂ v ₂ coordinate system (hereinafter referred to as a left image plane coordinate system) is provided at a position that is away from the installation position of the camera 5L in the z direction by the focal length f, and the u ₂ axis of the left image plane coordinate system is The x axis is parallel, the v ₂ axis is parallel to the y axis, and the intersection with the z axis is the origin O ₂ of the right image plane coordinate system. In this case, the predetermined range of the right image plane coordinate system is the image plane 52R of the camera 5R, and the predetermined range of the left image plane coordinate system is the image plane 52L of the camera 5L. The image point of the object D with respect to the camera 5R is P _R (u _R , v _R ), and the image point with respect to the camera 5L is P _L (u _L , v _L ).

Under the above conditions, the distance to the object D is z _d and can be calculated by the following equation (13). Therefore, the distance b between the camera 5R and 5L, the focal length f of the camera 5R and 5L, based on the coordinates of the image point P _R and P _L of the image plane coordinate system, the distance z to the object D _d can be calculated, and the distance from the vehicle 1 equipped with the cameras 5R and 5L to the object D can be acquired. Note that the coordinate transformation from the image coordinate system of the images captured by the cameras 5R and 5L to the image plane coordinate system can be performed using the above-described equations (11) and (12), and thus the description thereof is omitted. .

  The drive recorder according to the modification calculates the distance to the object ahead of the vehicle 1 based on the images captured by the cameras 5R and 5L of the imaging unit 109, and the vehicle 1 based on the images captured by the cameras 6R and 6L. The distance to the object behind the vehicle is calculated, the distance to the left object of the vehicle 1 is calculated based on the images captured by the cameras 7R and 7L, and the vehicle is calculated based on the images captured by the cameras 8R and 8L. The distance to the object on the right side of 1 is calculated. The distance to the object is acquired by the sonars 10 to 14 of the ultrasonic detector 19. When the distance to the target object obtained from either of them is closer than a predetermined distance, a collision between the target object and the vehicle 1 is expected, so that the image is captured by the imaging unit 109 and stored in the volatile memory 23. The stored image is recorded in the nonvolatile memory 24.

  In the drive recorder according to the modified example of the above configuration, the vehicle 1 is not moving by adopting a configuration in which each of the front, rear, left and right directions of the vehicle 1 is imaged by two cameras and the distance to the object is calculated. Even in this case, since the distance to the object can be calculated, the image can be recorded more reliably.

1 is a schematic plan view showing a configuration of a vehicle equipped with a drive recorder according to the present invention. It is a block diagram which shows the structure of the drive recorder which concerns on this invention. It is a schematic diagram for demonstrating the method of distance calculation which the drive recorder which concerns on this invention performs. It is a schematic diagram for demonstrating the acquisition method of the image point _Pn and the coordinate of _{Pn + 1 in} an image surface coordinate system. It is a flowchart which shows the procedure of the image recording process which CPU of the control part of the drive recorder which concerns on this invention performs. It is a block diagram which shows the structure of the drive recorder which concerns on the modification of this invention. It is a schematic diagram for demonstrating the method of distance calculation which the drive recorder which concerns on the modification of this invention performs.

Explanation of symbols

1 vehicle 5, 6, 7, 8 camera (imaging means)
DESCRIPTION OF SYMBOLS 9 Image pick-up part 10, 11, 12, 13, 14 Sonar 19 Ultrasonic detection part 20 Control part 21 CPU (calculation means, determination means)
22 ROM
23 Volatile memory (storage means)
24 Nonvolatile memory (recording means)

Claims (7)

In a drive recorder that is mounted on a vehicle and includes an imaging unit that images the surroundings of the vehicle, and a recording unit that records an image captured by the imaging unit.
Calculating means for calculating a distance to an object captured in an image captured by the imaging means;
Determination means for determining whether the distance calculated by the calculation means is closer than a predetermined distance,
The drive recorder, wherein the recording unit records an image captured by the imaging unit when the determination unit determines that the distance to the object is closer than a predetermined distance. A storage unit that temporarily stores an image captured by the imaging unit;
When the determination unit determines that the distance to the object is closer than a predetermined distance, the image stored by the storage unit is provided to the recording unit;
2. The drive recorder according to claim 1, wherein the recording means records an image captured by the imaging means provided from the storage means.   3. The recording device according to claim 1, wherein the recording unit records an image captured at a predetermined time before and after the determination unit determines that the distance to the object is closer than a predetermined distance. 4. Drive recorder.   The calculating means is a distance to the object based on an imaging position of the same object in a plurality of images taken by the imaging means at different time points and a moving distance of the vehicle between the different time points. The drive recorder according to any one of claims 1 to 3, wherein the drive recorder is calculated. The imaging means is a plurality, and is disposed in the vehicle at a predetermined distance,
The plurality of imaging means are capable of imaging the same object from different positions,
The calculation means calculates a distance to the object based on an imaging position of the same object in an image captured by each of a plurality of imaging means and the predetermined distance. The drive recorder as described in any one of Claim 3.   6. The image pickup device according to claim 1, wherein the image pickup means is arranged on each of a front side, a rear side, and a left and right side of the vehicle, and picks up an image of the periphery of the vehicle over 360 degrees. The drive recorder as described in one. Detection means for detecting the distance to the object by sonar;
Determination means for determining whether the distance detected by the detection means is shorter than a predetermined distance,
7. The recording device according to claim 1, wherein when the determination unit determines that the distance to the object is closer than a predetermined distance, the recording unit records an image captured by the imaging unit. Drive recorder described in 1.

Images