JP5478159B2 - Drive recorder - Google Patents

Description

  The present invention relates to a drive recorder, and more particularly to a drive recorder that stores video information taken before and after an impact generated in a vehicle.

  In recent years, drive recorders that continuously record information related to vehicle conditions, such as forward video and speed history, have been widely adopted by transportation companies as an effective means of analyzing the situation at the time of an automobile accident. . The drive recorder incorporates a CCD (Charge Coupled Device) camera, an acceleration sensor, a card-like storage medium, and the like, and always stores an image of the vehicle and the surrounding situation from the viewpoint of the driver. In general, video that has been shot and temporarily stored is set so as to save only video related to an impact that exceeds a preset abnormality level in order to save the storage capacity of the storage medium (memory).

  In order to effectively use the limited memory resources, it is necessary to correctly distinguish between an impact related to an accident such as a collision and other impacts and to store only video information related to the accident or the like. However, on the other hand, there is a request to store other video information at the time of occurrence of an impact for accident prevention and analysis, and conventionally, a drive recorder that can set the impact determination level low has been proposed (for example, , See Patent Document 1).

  For example, in the drive recorder disclosed in Patent Document 1, the acceleration detected by the acceleration sensor is distinguished between the gravity direction and the horizontal direction (traveling direction), the horizontal acceleration exceeds a predetermined threshold, and the gravity direction When the acceleration of the vehicle does not exceed a predetermined threshold, it is determined as an “impact” to be stored together with the determination regarding the presence or absence of the vehicle in the front image.

JP 2007-83964 A

  In practice, however, the seams and steps of road surfaces are very different in size and shape, and it is difficult to set appropriate thresholds. In practice, impacts (noise) and collisions associated with passage of seams, etc. are difficult. There was a problem that it was not possible to effectively distinguish the impact to be stored.

  In the drive recorder disclosed above, typical collisions such as rear-end collisions on flat lanes are reliably preserved. There is a problem that video information that should be saved as a shock case similar to a collision is judged to be noise and is not saved.

  As described above, the conventional drive recorders have a problem that the acceleration in the direction of gravity cannot be properly used for noise determination, and erroneous recording and recording omission due to erroneous determination cannot be completely eliminated.

  By the way, it is known that the vertical impact caused by the passage of road joints and the like frequently generated during driving is accompanied by the vertical displacement at the FOE (Focus of Expansion) point of the front image.

  Here, the FOE point is also referred to as an infinite point. For example, the FOE point can be set at a point where extension lines obtained by extending a pair of white lines located on both sides of the own lane on the road surface on which the own vehicle should travel intersect. it can. Although the forward image of the camera mounted on the traveling vehicle changes from moment to moment, a velocity vector (optical flow) can be obtained by connecting the same corresponding points with straight lines in the images at time t and time t + Δt. All optical flows appear radially from one point in the image. This one point is the FOE point.

  It is expected that more accurate noise determination can be performed if the amount of displacement of the FOE point is determined together with the acceleration in the direction of gravity.

  The present invention has been made in view of the above-described circumstances, and its object is to prevent erroneous recording by accurately identifying an impact accompanied by acceleration in the direction of gravity, such as when passing through a seam on a road surface. An object of the present invention is to provide a drive recorder that can reduce wastefulness.

In order to achieve the above-mentioned object, the drive recorder according to the present invention is characterized by the following ( 1 ).
(1) An imaging unit that is mounted on a vehicle and generates video information obtained by imaging the periphery of the vehicle;
Processing the video information acquired from the imaging means, white line detecting means for detecting a pair of white lines located on both sides of the own lane on the road surface on which the host vehicle should travel;
FOE setting means for setting an intersection point formed by an extension of the pair of white lines detected by the white line detection means as a FOE (infinite point);
Impact detecting means for detecting acceleration generated in the vehicle;
A collision determination unit that determines whether or not the video information is a storage target based on the acceleration detected by the impact detection unit and the displacement amount of the FOE point of the video information;
Control means for storing the video information determined by the collision determination means to be stored in a storage medium and prohibiting overwriting of a storage area of the storage medium in which the video information is stored;
With
The collision determination means includes
The image when the horizontal acceleration is larger than a predetermined set value, and when the horizontal acceleration is equal to or lower than the predetermined set value, the acceleration in the gravitational direction is larger than the predetermined set value, and before and after the acceleration is detected When the displacement amount of the FOE point of information is larger than a predetermined set value, the video information is determined as a storage target,
When the acceleration in the horizontal direction is less than or equal to a predetermined set value and the acceleration in the gravitational direction is less than or equal to a predetermined set value, and when the acceleration in the horizontal direction is less than or equal to a predetermined set value and the acceleration in the gravitational direction is a predetermined set value When the displacement amount of the FOE point of the video information before and after detecting the acceleration is larger than a predetermined set value, it is determined that the video information is not a storage target .

According to the drive recorder having the above configuration (1), for the impact detected by the impact detection means, when the acceleration in the horizontal direction is equal to or lower than a predetermined set value and the acceleration in the gravitational direction is greater than the predetermined set value, The collision determination means calculates the displacement amount of the FOE point of the video before and after the detected impact, and determines whether the video information related to the impact is a storage target based on the magnitude of the displacement amount. When it is determined that the image is to be saved, the control means saves the video information before and after the detected impact in the storage medium and prohibits overwriting the storage area in which the video information is stored. Since the video information recorded on the storage medium as a storage target is not overwritten, important information is not erased.
Further , the collision determination means determines whether or not the displacement amount of the FOE point of the image before and after the impact is smaller than a predetermined setting value. If the displacement amount is smaller than the predetermined setting value, the detected impact is a road joint. It is an impact that occurs when the vehicle passes, and is determined not to be a collision.

As described above, according to the drive recorder of the present invention, since it is determined whether or not there is a collision (impact to be stored) using both the acceleration and the displacement amount of the FOE point, when the road joint passes. It is possible to prevent erroneous recording of noise. Therefore, the memory capacity can be used effectively.
Further, when the displacement amount of the FOE point is smaller than a predetermined set value, it is determined that the detected impact is noise, so that erroneous recording of noise such as when a road joint passes is prevented with high accuracy. be able to. Therefore, the memory capacity can be used effectively.
In addition, when the impact generated on the vehicle is the impact to be stored, overwriting of the video information stored in the storage medium is prohibited, so that important video information is prevented from being erased by overwriting. it can. Therefore, it is not necessary to increase the capacity of the storage medium, and the cost can be reduced.

  The present invention has been briefly described above. Further, details of the present invention will be further clarified by reading through the modes for carrying out the invention described below with reference to the accompanying drawings.

It is a figure which shows the basic composition of the drive recorder which concerns on this invention. It is a block diagram which shows an example of schematic structure of a drive recorder. It is a flowchart which shows an example of the process outline | summary which concerns on this invention which CPU of FIG. 2 performs. It is a flowchart which shows an example of the process outline | summary of the FOE setting process in the flowchart of FIG. It is a flowchart which shows an example of the process outline of the collision detection process in the flowchart of FIG.

  Hereinafter, an embodiment of a drive recorder according to the present invention will be described with reference to the drawings of FIGS.

  First, FIG. 2 is a configuration diagram showing an example of a schematic configuration of the drive recorder of FIG. As is well known, the drive recorder 1 is attached to the inner surface of the windshield of the vehicle at, for example, substantially the same position as the rearview mirror so as not to disturb the driver's view.

  As shown in FIG. 2, the drive recorder 1 includes a central processing unit (CPU) 30 that performs various processes and controls according to a predetermined program, and a ROM 31 that is a read-only memory that stores programs for the CPU 30 and the like. The RAM 32 is a readable / writable memory that stores various data and has an area necessary for the processing operation of the CPU 30.

  The CPU 30 is also connected to an electrically erasable / rewritable read-only memory 33 that can retain the stored contents even while the apparatus main body is in an off state. The memory 33 is photographed by cameras 10a to 10n described later. And a temporary storage area for storing video information such as images in a time-sequential manner over a predetermined desired range.

  The CPU 30 described above determines whether or not the detected impact is to be stored, the white line detecting means 30a for detecting a pair of white lines positioned on both sides of the own lane on which the host vehicle should travel, the FOE setting means 30b for setting the FOE. Collision determining means 30c for determining, overwrite prohibiting means 30d for setting prohibition of overwriting on video information to be saved, storage control means for controlling whether or not to perform storage in a storage medium depending on whether or not it is to be saved Work as 30e.

  The drive recorder 1 further includes cameras 10a to 10n, acceleration sensors 20a to 20n, a card insertion unit 40, and the like. The cameras 10a to 10n are connected to the CPU 30 via interface circuits (I / F) 11a to 11n, respectively.

  The cameras 10a to 10n correspond to the imaging means in the claims, and various cameras such as a CCD (Charge Coupled Device) camera, a digital camera, a video camera, and an infrared camera can be used. The cameras 10a to 10n constantly take pictures of the surroundings of the vehicle, and the taken video signals are converted and compressed by the interface circuits 11a to 11n and input to the CPU 30 as video information.

  The CPU 30 stores the input video information in the memory 33 in time series. Note that the video information is arbitrarily determined according to the configuration, specifications, etc. of the drive recorder such as moving images and still images.

  In addition, the cameras 10b to 10n can be placed at any location of the vehicle so as to photograph the rear, the periphery, the driver of the vehicle, the driver of the vehicle for business use, the passenger, the inside of the vehicle, the door for getting on and off, etc. Is provided. As described above, by arranging the plurality of cameras 10b to 10n at desired locations of the vehicle, it is possible to collect video information that contributes to the cause analysis of the impact. In the present embodiment, a case where a plurality of cameras 10a to 10n are used will be described. However, various forms such as a single camera 10a may be used.

  The acceleration sensors 20a to 20n correspond to the impact detection means in the claims, and are formed by triaxial acceleration sensors that detect acceleration, inclination, impact, etc. in the triaxial (X, Y, Z) directions. As is well known, the triaxial acceleration sensor supports a weight by a thin silicon beam (beam), the weight is moved by acceleration, the beam is distorted, and this distortion is applied to a piezoresistive element or the like formed on the beam. The acceleration is detected by resistance change. The acceleration sensors 20a to 20n output the acceleration signals in the triaxial directions indicating the detected accelerations to the CPU 30, respectively.

  In the present embodiment, the acceleration sensors 20a to 20n are installed corresponding to the cameras 10a to 10n described above, the acceleration sensor 20a is provided inside the housing, and the acceleration sensors 20b to 20n are respectively connected to the cameras 10b to 10n. It is installed in the vicinity of the place where 10n is installed. By installing the acceleration sensors 20a to 20n in this way, it is possible to collect video information corresponding to the impact generated at the location where the cameras 10a to 10n are installed, and further contribute to the cause analysis of the impact generated on the vehicle. be able to.

  The card insertion unit 40 writes and reads various data designated by the CPU 30 with respect to the loaded card 50. The card 50 is manually inserted into the insertion section 40, and the card 50 is automatically discharged by a discharge mechanism (not shown) in the card insertion section 40 in accordance with the operation of the discharge key.

  In the present embodiment, the case where the card 50 inserted into the card insertion unit 40 is a storage medium in the claims will be described, but the present invention is not limited to this, and the storage medium of the present invention It is possible to adopt various forms such as the memory 33 or a newly built hard disk device.

  The ROM 31 described above stores various programs for causing the CPU 30 (computer) to function as the white line detection means, FOE setting means, collision determination means, overwrite detection means, and storage control means described in the claims. The ROM 31 also stores determination conditions for determining whether or not the impact is to be saved. This determination condition is held as acceleration determination threshold data for the X axis, the Y axis, and the Z axis for each of the acceleration sensors 20a to 20n.

  As described above, the memory 33 has a video information storage area for storing video information in time series, and a video information storage area for storing video information when overwriting on the card 50 is prohibited. . The video information storage area is sequentially stored from the top address every time video information is detected, and when the area is stored up to the end address, the video information is overwritten and stored again from the top address. By using the overwrite function in this way, a limited storage area is efficiently used.

  The card 50 uses a memory card such as a CF card, for example. As is well known, the card 50 has a memory whose stored contents are not erased even if it is not energized, and a controller circuit that handles external input and output. . As the card 50, various types of memory cards can be used depending on the system configuration.

  The card 50 has a video information storage area for recording video information temporarily stored in the memory 33. The size of the video information storage area is set according to a predetermined time range before and after detecting an impact in the vehicle. Similarly to the video information storage area of the memory 33, the video information storage area is also overwritten and stored.

  In the present embodiment, a description will be given of a case where the overwriting condition is that overwriting is performed from the top address every time an impact is detected. However, as the overwriting condition, the amount of data to be stored is the free space in the video information storage area. It is possible to adopt various forms such as a larger case. Note that save mode information indicating whether or not to overwrite the card 50 is stored in the memory 33, and the initial setting indicates overwrite save.

  Next, an example of the processing outline of the present invention executed by the CPU 30 of the drive recorder 1 will be described. FIG. 3 is a flowchart showing an example of a processing outline according to the present invention executed by the CPU of FIG. Here, in order to simplify the description, the case where the camera 10a and the acceleration sensor 20a correspond to each other will be described. However, the basic processing is the same for the other cameras 10b to 10n and the acceleration sensors 20b to 20n.

  When power is supplied via the power cable and the CPU 30 is started and initial processing is executed, predetermined initial values are set in various areas of the RAM 32, and the storage mode information in the memory 33 is set to the initial values. A certain overwrite save is set.

  First, video information (frame F0) ahead of the vehicle at time 0 is captured from the camera 10a, and the video information is stored in the memory 33 so that the captured cameras 10a to 10n can be identified (step S01). In addition, as a method of identifying the cameras 10a to 10n, for example, a storage area corresponding to the cameras 10a to 10n is set in the memory 33 in advance and stored in the corresponding area, or the cameras 10a to 10n are included in the video information. It is possible to adopt various forms such as a method of associating the identification data.

  Next, the CPU 30 sets the FOE point (initial value) in the frame F0 for the video information of the frame F0 stored in the memory 33 (step S02). As will be described later, the FOE point can be set by detecting a pair of white lines included in the image of the frame F0 and obtaining an intersection formed by the extension lines of the white lines.

Thereafter, the camera 10a captures video information (frame F _t ) ahead of the vehicle at an arbitrary time t, stores it in the memory 33 (step S03), and performs FOE point setting processing at F _t (step S04).

FIG. 4 is a flowchart showing an example of the processing outline of the FOE setting process in the flowchart of FIG. First, CPU 30 (white line detection unit 30a), for a video frame F _t, the vehicle by utilizing techniques well-known image processing to detect a pair of white lines located on both sides of the own traffic lane should travel (step S21 ). Then, CPU 30 (FOE setting means 30b) is to draw the extension line of the detected white line, the extension line to set the point of intersection as FOE point _{P t} in the frame _{F t} (step S22). The position information according to the set P _t are also temporarily stored in the memory 33. The FOE point setting process is performed by the above procedure. It should be noted that methods relating to white line detection and FOE point setting are well known, and therefore detailed description thereof is omitted.

Returning to the flowchart of FIG. 3, then, CPU 30 (collision determining means 30c) determines the collision determining whether an impact has been detected in response to a frame F _t obtained is an impact in which to store the object, such as a collision Processing is performed (step S05).

  FIG. 5 is a flowchart illustrating an example of a process outline of the collision determination process in the flowchart of FIG. 3. First, the acceleration signal input from the acceleration sensor 20a is acquired as acceleration information indicating acceleration, tilt, impact, etc. in the three-axis (X, Y, Z) directions (step S31). Next, the CPU 30 determines whether or not the acceleration in the X-axis direction and the Y-axis direction (acceleration in the horizontal direction of the vehicle) Gh of the acceleration information stored in the memory 33 exceeds a predetermined value. Is determined (step S32).

  When Gh does not exceed the predetermined value (N in Step S32), the CPU 30 then determines that the acceleration in the Z-axis direction (acceleration in the gravity direction) Gv of the acceleration information stored at the time t stored in the memory 33 is in advance. It is determined whether or not the set predetermined value is exceeded (step S33).

If Gv exceeds the predetermined value (Y in step S33), then, CPU 30, for location _{P t} of FOE point at time t stored in the memory 33, the frame _{F t-1} of the immediately preceding It is determined whether or not the displacement amount | P _t −P _t−1 | from the position information P _t−1 exceeds a predetermined value set in advance (step S34).

If the amount of displacement does not exceed the predetermined value (Y in step S34), CPU 30 may impact by the frame shock corresponding to F _t, that is, the acceleration by the acceleration sensor 20a detects the seam and the step of path passing such It is determined that it is (noise) (step S35).

On the other hand, if the amount of displacement exceeds the predetermined value (N in step S34), CPU 30 determines that an impact corresponding to the frame F _t is the impact of storage target of collision (step S36). Also, if the Gv does not exceed the predetermined value in step S33 (N in step S33), CPU 30 may impact corresponding to the frame _{F t} is determined not to correspond to the collision with minute (step S37). Moreover, even if Gh exceeds the predetermined value in step S32 (Y in step S32), CPU 30 is (determining the impact corresponding to the frame F _t is the great impact of storage object such as a collision S36).

  Finally, the CPU 30 outputs the presence / absence of a collision (a shock to be stored) (step S38).

Returning to the flowchart of FIG. 3, next, the CPU 30 (storage control means 30e) determines whether or not there is a collision (impact to be stored) (step S06). If the impact is to be saved (Y in step S06), the CPU 30 (overwrite prohibiting means 30d) sets the overwrite prohibition flag for the video information from the frame F _{t -m} to the frame F _t temporarily stored in the RAM 32. (Step S07). On the other hand, if it is not an impact to be stored (N in step S06), the CPU 30 (overwrite prohibiting means 30d) does not set the overwrite prohibition flag. The range for storing video information (or the range for setting the overwrite prohibition flag) can be configured to store video information after detection of impact according to the specifications of the drive recorder.

Next, the CPU 30 (storage control means 30e) stores (writes) video information in a predetermined range stored in the RAM 32 into the video storage area at the time of the collision of the card 50 via the card insertion unit 40. already it determines whether the total data size of the video information according to the frame and the frame F _t stored exceeds the memory capacity of the card 50 (step S08).

If it does not exceed the memory capacity (N in step S08), and writes the image information according to the frame F _t to the free memory area (step S09). On the other hand, (Y in step S08) if it exceeds the memory capacity, the frame data overwrite protection flag is not set to overwrite the image information according to the frame F _t in the memory area written (step S10).

  As described above, the video information related to the impact that is not the storage target is recorded, but can be overwritten and deleted thereafter. Since only necessary video information is finally stored in the card 50, unnecessary video information is not stored in the card 50. Further, the video information to be saved is prevented from being erased by overwriting. In the present embodiment, the video information to be stored in the card 50 has been described. However, the present invention is not limited to this, and the video information may be stored in the memory 33. Further, it may be stored in the card 50 at the beginning, and when the storage capacity of the card 50 is insufficient, the storage area of the memory 33 may be borrowed.

  Next, the CPU 30 increments the time t (step S11), and repeats the procedure from step S03 to step S10 for the incremented time. Therefore, while the drive recorder 1 is being activated, the video around the vehicle and the collision determination are continuously executed.

  According to the drive recorder 1 described above, for the impact detected by the acceleration sensor 20a, when the horizontal acceleration is smaller than a predetermined set value and the acceleration in the gravitational direction is larger than the predetermined set value, the collision determination means 30c calculates the displacement amount of the FOE point of the video before and after the detected impact, determines whether the video information related to the impact is a storage target based on the magnitude of the displacement amount, and stores the video information of the storage target Since only video data is stored in the card 50, unnecessary video information can be prevented from being stored in the storage medium. Accordingly, video information corresponding to the impact level desired by the user can be stored in the card 50 without increasing the storage capacity of the card 50.

  The above-described embodiments are merely representative examples of the present invention, and the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the present invention. be able to.

1 Drive recorder 10a to 10n Imaging means (camera)
20a to 20n Impact detection means (acceleration sensor)
30 CPU
30a White line detection means (CPU)
30b FOE setting means (CPU)
30c Collision judging means (CPU)
30d Overwrite prohibition means (CPU)
30e Storage control means (CPU)
31 ROM
32 RAM
33 Memory 40 Card insertion section 50 Storage medium (card)

Claims (1)

An imaging means mounted on the vehicle for generating video information obtained by imaging the vehicle periphery;
Processing the video information acquired from the imaging means, white line detecting means for detecting a pair of white lines located on both sides of the own lane on the road surface on which the host vehicle should travel;
FOE setting means for setting an intersection point formed by an extension of the pair of white lines detected by the white line detection means as a FOE (infinite point);
Impact detecting means for detecting acceleration generated in the vehicle;
A collision determination unit that determines whether or not the video information is a storage target based on the acceleration detected by the impact detection unit and the displacement amount of the FOE point of the video information;
Control means for storing the video information determined by the collision determination means to be stored in a storage medium and prohibiting overwriting of a storage area of the storage medium in which the video information is stored;
With
The collision determination means includes
The image when the horizontal acceleration is larger than a predetermined set value, and when the horizontal acceleration is equal to or lower than the predetermined set value, the acceleration in the gravitational direction is larger than the predetermined set value, and before and after the acceleration is detected When the displacement amount of the FOE point of information is larger than a predetermined set value, the video information is determined as a storage target,
When the acceleration in the horizontal direction is less than or equal to a predetermined set value and the acceleration in the gravitational direction is less than or equal to a predetermined set value, and the acceleration in the horizontal direction is less than or equal to a predetermined set value and the acceleration in the gravitational direction is a predetermined set value A drive recorder characterized in that if the displacement amount of the FOE point of the video information before and after detecting the acceleration is larger than a predetermined set value, the video information is determined not to be stored .

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