JP3004570B2 - Road surface crack detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road surface crack detecting device having a continuous road surface image acquiring function for detecting cracks in road surface property measurement.

[0002]

2. Description of the Related Art Conventionally, crack detection in road surface property measurement has been performed by a method as shown in FIG. This figure 4
Is a method in which a rope (mesh rope) of, for example, 50 cm is installed on a road surface 41, and a crack on the road surface in the rope is sketched by a person (measurer) 43 on a sketch board 44 and evaluated. there were.

[0003]

The above-described conventional crack detection method is time-consuming because a net is laid on a road surface and a person transcribes a road surface condition (cracked), so that restrictions such as traffic rules on roads and the like are imposed. There was a problem that occurred.

[0004] There is also a problem that there is a variation in measurement accuracy due to individual differences in measurement and human fatigue. The present invention has been made in view of the above points, and an object of the present invention is to provide a road surface crack detection device capable of performing crack detection in road surface property measurement without requiring traffic regulation and the like, and that can be performed quickly and accurately. It is in.

[0005]

SUMMARY OF THE INVENTION The present invention relates to an image pickup means (road image pickup means) for acquiring and outputting a road image every predetermined time and a traveling distance of a vehicle in order to quickly measure cracks on the road surface. A configuration in which a distance measuring unit that measures and outputs distance data and a distance data capturing unit that captures distance data from the distance measuring unit in synchronization with the image acquisition timing of the imaging unit is mounted on a measurement vehicle, Based on each road surface image acquired by the imaging unit at regular intervals and the corresponding distance data captured by the distance data capturing unit, the amount of overlap of the road surface between successive road surface images is calculated, and the amount of overlap is calculated. A video editing unit that edits a road surface image while cutting the overlapped portion, and cracks on the road surface by performing image processing on the image edited by this video editing unit Characterized by being configured to include an image processing means for output.

Here, the video editing means cuts the road surface data acquired by the imaging means, that is, the video data of the frame, at an arbitrary position corresponding to each frame (a position determined by the overlapping amount), and cuts the necessary data. The video portion is stored in a separately prepared video frame for editing, and a blank portion in the frame further stores a video cut at an arbitrary position from the next video frame, and when one frame is filled, It has an editing function of storing the part of the video that was added immediately before that that could not be stored (cannot be additionally stored) in the next video frame for editing.

In the above configuration, the road surface image pickup means such as a two-dimensional CCD camera mounted on the measuring vehicle converts the road surface image at a constant time interval (for example, every 1/30 second) in the running state of the vehicle. Acquired and output as video data (video frame data).

[0008] Similarly to the road surface image capturing means, the distance data capturing means mounted on the measuring vehicle captures distance data from the distance measuring means in each case in synchronization with the image acquisition timing of the road surface capturing means.

[0009] Since the road surface imaging means obtains one image at regular intervals, the image frame data output from the road surface imaging means has an overlap of images that change depending on the traveling speed of the vehicle.

Therefore, the video editing means (the overlap amount detecting means therein) uses the distance data fetched by the distance data fetching means at the acquisition timing of each video, that is, the distance data of each video, based on the distance data of each video and the immediately preceding video. Video (previous video)
Is calculated (overlap width, overlap amount). Then, the video editing means determines, in one video (road surface video frame), a portion overlapping with the previous video,
The video clip is cut (cut) based on the calculated amount of overlap, and the remaining video portion is stored in a video frame for editing.

The video editing means also stores a non-overlapping portion in an editing video frame (editing screen frame) based on the amount of overlap with respect to a subsequent video (next video), and one editing video frame. Is satisfied, it is stored in the next editing video frame.

[0012] As described above, the image acquired at regular intervals by the imaging means mounted on the measuring vehicle is edited into a continuous image of the road surface by the image editing processing of the image editing means. Therefore, this edited video (continuous road surface video)
Is subjected to image processing by the image processing means, whereby cracks on the road surface are extracted with high accuracy.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration of a road surface crack detection device according to an embodiment of the present invention, and FIG. 2 is a diagram showing a processing flow in the embodiment.

The road surface crack detecting device according to the present embodiment includes a measuring unit shown in FIG. 1A and a processing unit shown in FIG. 1B. First, the configuration and operation of the measurement unit in FIG. 1A will be described with reference to the upper part (steps 201 to 207) of the processing flow in FIG.

The measuring section shown in FIG. 1 (a) fixes a CCD camera (two-dimensional CCD camera) 1 as a road surface image pickup means to a measuring vehicle 12 toward the road surface and travels in order to acquire a road surface image. The CCD camera 1 is operated at regular intervals, for example, 1
/ One image (road surface image) is acquired every 30 seconds.

Each video (signal) acquired by the CCD camera 1 every 1/30 second includes a video acquisition timing signal every 1/30 second (hereinafter referred to as a 1/30 second signal). It is output to a video recording VTR (video tape recorder) 2 as a video recording means mounted on the vehicle 12 (step 201).

VTR 2 is 1/3 from CCD camera 1
The video (video frame data) every 0 seconds is recorded on a storage medium (B) 5 such as an 8 mm tape or a VHS tape mounted on the VTR 2 according to a 1/30 second signal (step 202). At the same time, VTR2
A 30-second signal is output to the computer 3 as distance data capturing means (control device) mounted on the vehicle 12.

A distance meter 4 is mounted on the vehicle 12.
The distance meter 4 measures the traveling distance of the vehicle 12 and outputs distance data e (step 203). Calculator 3
Is connected to the distance meter 4 and is 1/30
Every time a second signal is received, the distance data e output from the distance meter 4 at that time, that is, the distance data e corresponding to one frame every 1/30 second recorded on the storage medium (B) 5, At the time t (step 20).
4) The distance data e is recorded on the storage medium (A) 6, such as a floppy disk or a magneto-optical disk (step 205). Note that the time t in the present embodiment is not an actual time but a relative time (elapsed time) based on the measurement start time.

At the end of a series of measurement processes while the vehicle 12 is running (step 206), the computer 3 sets the time t acquired at that time as the measurement end time (final time) t to the storage medium (A) 6 (Steps 207 and 20)
5).

Next, the configuration and operation of the processing unit shown in FIG. 1B will be described with reference to the lower part of the processing flow shown in FIG.
01 to 313) as needed. FIG.
The processing unit in (b) acquires the road surface image every 1/30 second (in the storage medium (B) 5) and the corresponding (in the storage medium (A) 6) acquired by the measurement unit in FIG. A) a function of acquiring an image of a continuous road surface based on the distance data, extracting a corresponding crack on the road surface from the continuous road image by image processing, and outputting the result.

Here, the frame number of the road image (road image screen frame) recorded in the storage medium (B) 5 is M, and the dimensions of the actual road surface of the road image (road image screen frame M) are shown in FIG. As shown in FIG. 3A, a measurement width w and a traveling direction length h are set. In addition, the length (overlap amount) of a portion that overlaps with the video one frame before is d (dm in the case of the road surface video screen frame M as described later).

In this embodiment, since a screen frame for editing (editing screen frame) is used in correspondence with a road surface image frame to edit a road surface image,
The frame number of the edit screen frame is L, and the dimensions of the actual road surface of the edit screen frame L are a measurement width w and a traveling direction length h, as shown in FIG. Also, let P be the length of the blank portion (the length of the blank portion of the edit screen) of the image that is the unedited portion (unrecorded portion) of the edit screen frame L.

In the processing section shown in FIG. 1B, first, an image of the road surface every 1/30 seconds is recorded by the measuring section (the recording VTR 2 therein) of FIG. 1A. B) 5 is mounted on a reproduction VTR 8 as a video reproduction means to perform video reproduction processing.

Then, the road surface video recorded on the storage medium (B) 5 is reproduced every 1/30 second, and the reproduced video (video frame data) is used for both image editing (video editing) and image processing. Is output to the image editing / processing device 9 having

The video frame output from the reproduction VTR 8 to the image editing / processing device 9 overlaps the video one frame before. Therefore, in the processing unit of FIG. 1B, the storage medium (A) in which the distance data e corresponding to each image (road surface image) is recorded by the measuring unit (the computer 3 therein) of FIG. 1A. Based on the data of No. 6, the computer 7 (as an overlap amount calculating means) calculates the overlap amount of each video frame (road surface video screen frame).

Here, the overlap amount d of the m-th (m = M) road picture frame is dm, the distance data e corresponding to the m-th road picture frame (M) is em, and the immediately preceding distance d is em. The (m-1) th road surface image screen frame (M-
Assuming that the distance data e corresponding to 1) is em-1, the m-th overlap amount dm is calculated by the following equation.

Dm = h- (em-em-1) In this way, the computer 7 calculates the value of 1 by the reproduction VTR 8.
In synchronization with the reproduction output of the road image every 30 seconds, the overlap amount dm of the road image screen frame is calculated (step 303). The overlap amount dm calculated by the computer 7 is output to the image editing / processing device 9.

First, the image editing / processing device 9 sets the margin length P of the editing screen to the traveling direction length h (on the actual road surface) of the editing screen, the frame number M of the road surface video screen frame, and the editing screen frame. Are initialized to 1 (step 301).

The image editing / processing device 9 includes a storage medium (A)
As long as the value obtained by dividing the last time t recorded in No. 6 by 1/30 second is equal to or greater than the current value of M (the frame number of the road surface video screen frame) (step 302), the last time t
Assuming that the image editing processing up to the road image screen frame has not been completed, the following image editing operation is repeated every 1/30 second in synchronization with the reproduction output of the road image by the reproduction VTR 8.

First, the image editing / processing device 9 sets the playback VT
Frame number M reproduced by R8 (M = M
From the road surface image frame of 1), that is, from a road surface image having a width w and a length h (hereinafter referred to as a road surface image (w, h)),
The width w, which is obtained by cutting the video portion indicated by the overlap amount dm in the frame (calculated by the computer 7)
An image having a length h-dm (the image of the portion not shaded in FIG. 3A), that is, an image (w, h-dm) is created (step 304).

Next, the image editing / processing device 9 determines the margin length P (P = h at the beginning) of the current editing screen frame whose frame number is L (L = 1 at the beginning) and the image created at step 304 (P = h). w, h-dm) is compared with the length h-dm (step 305).

As a result of this comparison, if the length h-dm of the video (w, h-dm) is less than or equal to the margin length P of the editing screen frame L, the image editing / processing device 9 sets the (width w) ,
The video (w, h-dm) is set in the margin of the edit screen frame L (having a length h) (step 306).

In this case, the image editing / processing device 9 subtracts the margin length P of the editing screen frame L from the current P by the length h-dm of the video fitted in step 306.
-(H-dm) is updated (step 307).

Then, the image editing / processing device 9 advances the frame number M of the road surface image frame by one (step 308), and thereafter returns to step 302. If the new road surface video screen frame M does not exceed the frame at the last time t, the image editing / processing device 9 outputs the last time t
It is assumed that the image editing process up to the road surface video screen frame has not been completed,
, The video (w, h-dm) obtained by cutting the video portion indicated by the overlap amount dm in the new road surface video frame M reproduced by the reproduction VTR 8 (calculated by the computer 7). Create

If the created video (w, h-dm)
Is longer than the margin length P of the current editing screen frame L (step 305), the image editing / processing device 9 converts the entire video (w, h-dm) into the editing screen frame L. It is determined that the image cannot be fitted in the margin.

In this case, first, the image editing / processing device 9
Edit screen frame L from created video (w, h-dm)
Then, the video portion (w, P) corresponding to the margin length P is cut, and the video portion (w, P) is fitted into the margin portion of the length P of the editing screen frame L (step 309). As a result, the editing screen frame L is filled with the video having the width w and the length h.

Next, the image editing / processing device 9 outputs the remaining video portion (w, (h-dm) of the video (w, h-dm) created.
) -P) is inserted into the next edit screen frame L + 1 (step 310).

Then, the image editing / processing device 9 advances the frame number L of the editing screen frame by 1 and increases the margin length P of the editing screen frame L from the current P in steps 309 and 310 in the video portion (w , P),
The total length of (w, (h-dm) -P), that is, the length h-dm of the video (w, h-dm) created in step 304
Is updated to P- (h-dm) (Step 3)
11).

Next, the image editing / processing device 9 advances the frame number M of the road surface image frame by 1 (step 308), and returns to step 302. Eventually, when the value obtained by dividing the last time t recorded in the storage medium (A) 6 by 1/30 second becomes smaller than the value of M updated in step 308 (step 302), the image editing / processing device 9 sets It is determined that the image editing processing up to the road surface video screen frame at the last time t has been completed. At this time, the storage medium (B) 5
Each of the road surface images (images of M road surface image screen frames from frame number 1 to the current M) recorded in
Overlapping portions are cut on each of the L editing screen frames from frame number 1 to the current L, and edited into a continuous road surface video (continuous road surface video).

Therefore, the image editing / processing device 9 uses the image processing function to perform image processing for each of the road surface images of the L edit screen frames having the frame numbers 1 to L on a frame-by-frame basis. Is extracted (step 312).

Here, the crack is calculated based on the data of the two-dimensional coordinates (x, y) based on the position of the white line drawn at the measurement start point, and the two-dimensional coordinates (x, y) are used as the crack detection result ( Is output to the output device 10 together with, for example, a continuous road surface image (step 313). The continuous road surface image and the result of the crack detection are recorded in the storage device 11.

[0042]

As described above in detail, according to the present invention, an image pickup means for acquiring a road image at regular intervals and a distance for taking distance data from the distance measuring means in synchronization with the acquisition timing of the road image. By mounting the measurement unit provided with the data capturing means on the vehicle, the measurement can be performed while the vehicle is running by itself, so that traffic regulation and the like can be eliminated.

Further, according to the present invention, the amount of road surface overlap between road surface images is determined based on each road surface image acquired by the imaging means at regular intervals and the corresponding distance data acquired by the distance data acquisition means. By calculating and editing the road surface image while cutting out the overlapping part based on the amount of overlap, the road surface condition was acquired as a continuous road surface image, and it was processed to extract cracks. Accurate data can be obtained without any individual difference that occurs in a human sketch or the like, unlike the crack detection method, and with no variation in accuracy. That is, according to the present invention, crack detection in road surface property measurement does not require traffic regulation and the like,
Moreover, it can be performed quickly and with high precision.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a road surface crack detection device according to an embodiment of the present invention. FIG. 1 (a) is a block configuration diagram of a measurement unit, and FIG. 1 (b) is a block configuration of a processing unit. FIG.

FIG. 2 is a view showing a processing flow in the embodiment.

FIG. 3 is a diagram showing dimensions (on an actual road surface) and an overlap amount of a road image of a road image screen frame and a dimension (on an actual road surface) and a margin length of a road image of an edit screen frame in the embodiment. .

FIG. 4 is a view for explaining a crack detection method in a conventional road surface property measurement.

[Description of Signs] 1 ... CCD camera (imaging means), 2 ... VTR (recording VTR), 3 ... Computer (control device, distance data capturing means), 4 ... Distance meter, 5 ... Storage medium (B), 6 ... storage medium (A), 7 ... computer (overlap calculation means), 8 ... VTR (reproduction VTR), 9 ... image editing / processing device, 10 ... output device, 11 ... storage device, 12 ... vehicle (for measurement) vehicle).

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01B 11/00-11/30 102 G01B 21/00-21/32 G06T 1/00-7/00 E01C 21 / 00-23/16

Claims (1)

(57) [Claims] An imaging unit for acquiring a road surface image at predetermined time intervals; a distance measurement unit for measuring a traveling distance of a vehicle and outputting distance data; and synchronizing with an image acquisition timing of the imaging unit. A distance data capturing means for capturing distance data from the distance measuring means is mounted on the vehicle for measurement, and each road surface image acquired at regular intervals by the image capturing means and corresponding distance data captured by the distance data capturing means. Video editing means for calculating the amount of overlap of the road surface between the road images based on the overlap amount, and editing the road surface image while cutting off the overlapping portion based on the amount of overlap, and converting the image edited by the image editing means into an image. An image processing means for detecting a crack on a road surface by processing the road surface.