JP2004219130A - Pipe inner wall face image photographing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe inner wall face image photographing device capable of photographing to obtain a clear pipe inner wall face image having a suppressed image distortion. <P>SOLUTION: On the hull (floating body) 4 of the pipe 19 inner wall face image photographing device, an omnidirectional mirror 1, a still camera 2, a stroboscopic light emitting device 3, a tilt angle detector 7, a laser pointer 8, and an information processing device 9 for controlling image photographing, are loaded. The pipe inner wall face image photographing device is equipped with an information processing device 7 of the hull 4, an image processing device 10, a recording device 11, a rotation detector 14, a data input device 16, an information processing device 17, and an image display device 13. The on-board information processing device 9 acquires a pitching angle α and a rolling angle β of the hull 4 by the tilt angle detector 7, and if each angle is not near 0°, waiting is required until the time (to) comes or until the angles approach near 0°. When the elapsed time T reaches the time (to) or when each angle approaches near 0°, the still camera 2 drives the stroboscopic light emitting device 3, and photographs sequentially therewith. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pipe wall image capturing apparatus that captures image information for investigating the state of the inner wall surface of a pipe such as a sewer.
[0002]
[Prior art]
In pipes such as sewers, it is necessary to investigate the state of deterioration of pipe inner walls. For example, in the sewer of a small diameter pipe, the running water is stopped, and a person operates a photographing machine, or a photographing machine equipped with an interchangeable lens, a fisheye lens, or the like, performs a remote operation or the like to take a picture while moving the inside of the pipe to check the state of the inner wall of the pipe. is investigating.
[0003]
The large-diameter sewer main line is always used for the small-diameter sewer, so it is difficult to stop the flowing water even if the running water level in the pipe can be lowered to some extent.
[0004]
As an in-pipe inspection system that is used at all times and is capable of investigating a large-diameter sewage trunk line in which it is difficult to stop flowing water in an in-pipe, there is an "inspection method and an in-pipe underground pipe" described in Patent Document 1.
[0005]
The technique described in Patent Document 1 is a technique in which a television camera is mounted on a hull and an inner wall surface of a pipe is photographed while being floated in flowing water.
[0006]
Patent Literature 2 describes “Processing apparatus and method of sewer inner surface image”. The technique described in Patent Document 2 uses a video camera equipped with a fish-eye lens or the like to simultaneously image 360 ° around the inner wall surface of a pipe, and converts an image taken on the entire circumference into an image developed on a plane to convert the image into a plane. This is a technique for observing the wall surface.
[0007]
[Patent Document 1]
JP-A-7-216972 [Patent Document 2]
JP 2000-331168 A
[Problems to be solved by the invention]
However, in the techniques described in Patent Literatures 1 and 2, since a television camera (video camera) is used, the standard photographing cycle is 1/30 second, which lacks sharpness. There is a problem that the image is blurred or distorted due to the sway of the hull due to the pulsation of the flowing water due to the presence of the water.
[0009]
Therefore, at the time of evaluating the inner wall surface of the pipe, it is necessary to visually select a clear image from a plurality of captured images and evaluate the wall surface based on the selected image.
[0010]
In other words, in the conventional technology, since the resolution of the video camera at the time of image capturing is low and the depth of the subject cannot be deepened, an enormous amount of image capturing is required in order to obtain an image in which the state of the inner wall surface of the tube can be observed well. However, there is a problem that the amount of editing work and the like become enormous.
[0011]
For this reason, it takes a long time before the evaluation result of the inner wall surface of the pipe is obtained.
[0012]
An object of the present invention is to realize a pipe wall surface image capturing apparatus that is capable of capturing a pipe wall surface image that is sharp and has reduced image distortion.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is configured as follows.
(1) an omnidirectional sensor, a still image photographing means for photographing an image obtained through the omnidirectional sensor, and a floating body mounted with the omnidirectional sensor and the still image photographing means and floating on a fluid, In the pipe inner wall surface image capturing device that captures an image of a pipe inner wall surface, a posture state measuring unit that measures a posture state of the floating body, a position detecting unit that detects a position of the floating body in a tube axis direction, and a position measured by the posture state measuring unit. When the posture state of the floating body matches the set condition and the position of the floating body in the tube axis direction detected by the position detecting means matches the set condition, the still image photographing means captures an inner wall surface image of the pipe. Image capturing control means.
[0014]
(2) Preferably, in the above (1), there is provided a pipe radial position detecting means mounted on the floating body to detect a radial position of the floating body, and the floating body detected by the pipe radial position detecting means is provided. Based on the position in the tube radial direction, the inner wall surface image captured by the still image capturing unit is corrected.
[0015]
(3) Preferably, in the above (1) or (2), the floating body is pulled by a rope, and the rope is wound by a rope winding means, so that the floating body is in the pipe axial direction. The position detection means detects the position of the floating body in the pipe axis direction by measuring the number of rotations of the winding means or by measuring a scale marked on a rope.
[0016]
(4) Preferably, in (1) above, the posture state is represented by a rolling angle and a pitching angle of the floating body.
[0017]
(5) Preferably, in the above (1), the still image photographing means photographs a plurality of images in the tube axis direction, and a part of images adjacent to each other overlaps with each other.
[0018]
(6) Preferably, in (1), the still image photographing means has a light emitting means for emitting light to a photographing target area.
[0019]
Preferably, the still image photographing means having the light emitting means is mounted on the floating body, and when the image is blurred due to the swing of the floating body, the shutter speed of the still image photographing means can be increased by the light emission of the light emitting means.
[0020]
Further, when the posture state of the floating body matches the set posture condition, the still image photographing means causes the inner wall surface image to be photographed.
[0021]
Thereby, a clear image with a deep depth of field can be obtained. By arranging the images thus photographed in the order of the photographing range, a practical and clear image can be obtained.
[0022]
Furthermore, regarding the distortion of the image due to the change in the water level and the deviation of the horizontal distance between the photographing position and the tube wall, for example, the position of the floating body is measured by the tube radial position detecting unit having a laser pointer, and from there, each floating unit from the photographing unit is measured. The image can be corrected by changing the compression ratio of the image in accordance with the angle expected to the wall element.
[0023]
[Practical mode of the invention]
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an overall schematic configuration diagram of a tube inner wall surface image capturing apparatus according to an embodiment of the present invention.
[0024]
In FIG. 1, an apparatus for photographing the inner wall surface of a pipe in a sewer pipe 19 includes a hull (floating body) 4, an omnidirectional mirror (omnidirectional sensor) 1, a still camera (still image photographing means) 2, and a strobe light emitting device 3. A hull 4 is provided with an inclination angle detector (posture state measuring means) 7, a laser pointer 8, and an information processing device (photographing control means) 9 for controlling image photographing.
[0025]
Further, the pipe inner wall surface image photographing apparatus includes wires (cord) 5a, 5b for pulling the hull 4 on water, winches (cord winding means) 6a, 6b, and image information data from the information processing device 9 of the hull 4. And a cable 18 for transmitting the data.
[0026]
Further, the tube inner wall surface image photographing device includes an image processing device 10 for processing a photographed image, a recording device 11 for recording image data, a rotation detector 14 for measuring the number of rotations of the winch 6a, and setting of image photographing. A data input device 16 for inputting values, an information processing device (shooting control means, position detecting means) 17 for transmitting image shooting information to the hull 4, and an image display device 13 are provided.
[0027]
The omnidirectional mirror 1 mounted on the hull 4 has a function of introducing the entire circumference (360 degrees) of the inner wall surface of the sewer pipe into the still camera 2. In addition, the strobe light emitting device 3 with a large amount of light serves as a light source for obtaining a clear image in a dark sewer.
[0028]
The hull 4 configured as above is floated in flowing water in the pipe 19, and the winch 6a is installed near the manhole 12a on the upstream side. Also, the winch 6b is installed near the downstream manhole 12b, and the wire 5b is wound around the downstream winch 6b while loosening the wire 5a wound around the upstream winch 6a. As a result, the hull 4 moves downstream from the upper stream of the water flow.
[0029]
In this case, the hull 4 moves in the sewer pipe 19 by synchronizing the rotational speed or the drawing length of the wire 5a or the drawing length of the wire 5b between the upstream winch 6a and the downstream winch 6b. It is possible to advance while restraining the course.
[0030]
Further, by measuring the number of rotations of the winch 6a by the rotation detector 14 or reading the scaled wire 5a, the position of the hull 4 in the sewer pipe 19 in the pipe axial direction can be known.
[0031]
The omnidirectional mirror 1 can reflect an image in a range of 360 degrees in the entire circumference of the inside of the tube 19, and when photographed along the tube axis at the center of the tube axis, the image is developed by image processing to eliminate distortion. It can be corrected to a rectangular planar image as shown in FIG. 4A (actually, since the omnidirectional mirror 1 is disposed on the hull 4, The walls are not shown).
[0032]
FIG. 4B shows a photographed image and a developed image when photographed at a position shifted from the tube axis.
[0033]
The imaging range of the omnidirectional mirror 1 capable of capturing an image of 360 ° around the circumference of the sewer pipe 19 is usually dark. For this reason, the still camera 2 captures an image at a shutter speed that is not affected by the sway of the hull 4. In this case, a large amount of light is emitted by the strobe light emitting device 3 in conjunction with the shutter of the still camera 2.
[0034]
Thereby, the depth of field of the camera 2 can be set deep, and a clear image of the angle-of-view range L (shown in FIG. 1) of the omnidirectional mirror 1 can be obtained.
[0035]
The laser pointer 8a is installed vertically upward with respect to the axis of the hull 4, and the laser pointers 8b and 8c are installed vertically and horizontally with respect to the axis of the hull 4. Then, the diametrical position Y of the pipe 19 in the direction perpendicular to the pipe 19 axis and the depth direction position Z of the water surface of the hull 4 of the hull 4 are determined by laser light from the laser pointer 8a, the laser pointers 8b and 8c. Can be measured.
[0036]
That is, the point indicated by the laser pointers 8a to 8b in the image of the pipe wall is image-processed by the image processing device 10, so that the position Y in the diametric direction of the hull 4 and the position Z in the depth direction of the water surface (Y, Z Indicates the position in the pipe radial direction). Note that the pipe diameter position measuring means (laser pointer 8, image processing device 10) of the hull 4 can be substituted by using a laser distance meter utilizing reflection of laser light from a measurement target.
[0037]
The inclination of the hull 4 in the pipe axis direction (pitching angle α) and the inclination in the pipe width direction (rolling angle β) are measured by an inclination angle detector 9 mounted on the hull 4 and transmitted to the information processing device 7.
[0038]
The image data and the tilt angle detection data collected in the information processing device 7 mounted on the hull 4 are transmitted to an image processing device 10 on the ground via a cable 18, and after image processing, are sent to an image display device (monitor) 13. The image is confirmed by the recording device 11 and the image is recorded.
[0039]
Next, with reference to FIG. 2, the overall processing operation of image capturing will be described.
In FIG. 2, information from the rotation detector 14, the tilt angle detector 9, and the data input device 15 are processed by the information processing device 7, and a photographing permission signal is transmitted to the still camera 2. The still camera 2 to which the photographing permission signal has been transmitted captures the image of the wall surface and the irradiation image of the laser pointer on the wall surface, and transmits the image to the image processing device 10 via the image transfer processing device 16.
[0040]
The image processing device 10 first performs an image recognition process 10d on the laser pointer image, converts the irradiation position on the inner wall surface of the tube into a coordinate value, and converts the coordinate position by the conversion process into the hull position (tube diameter direction position Y). And a process 10e for calculating the water surface depth direction position Z).
[0041]
Next, correction processing 10a of the wall image is performed from the hull position of processing 10e, and image development processing 10b is performed. Then, a process 10c of arranging and connecting the developed images in parallel is performed. The processed image is stored in the image storage processing unit 11a of the data recording device 11, and the hull position information is stored in the hull position recording processing unit 11b of the data recording device 11.
[0042]
FIG. 3 is a flowchart illustrating an image capturing algorithm used in the information processing device 17 and the onboard information processing device 9.
[0043]
In step 100 of FIG. 3, a set shooting distance interval Xo, a shooting permission pitching angle range αo, a shooting permission rolling angle range βo, and a shooting interval t0, which are initial values, are set.
[0044]
In step 101, the information processing device 17 acquires the rotation data of the rotation detector 14 attached to the winch 6a, and in step 102, calculates the current axial position X of the hull 4 in the pipe.
[0045]
Then, in step 103, the photographing permission signal is transferred to the onboard information processing device 9 via the cable 18 at every preset photographing distance interval Xo. That is, when the set distance X0 is reached, the information processing device 17 transfers the photographing permission signal to the onboard information processing device 9, resets the internal counter to 0, and returns to step 101. Then, the distance is measured, and when the distance further advances by the shooting distance X0, the information processing device 17 transfers a shooting permission signal to the onboard information processing device 9. This operation is repeated until the photographing target distance ends.
[0046]
In step 104, the onboard information processing device 9 to which the imaging permission signal has been transferred acquires the pitching angle α and the rolling angle β of the hull 4 based on the output signal from the inclination angle detector 7. In step 105, it is determined whether the pitching angle α and the rolling angle β are each near 0 °, that is, −αo <α <+ αo, and −βo <β <+ βo (that is, the inclination of the hull 4). Is moderate).
[0047]
If it is determined in step 105 that -αo <α <+ αo and not −βo <β <+ βo, the process proceeds to step 106, and the elapsed time T from when the photographing permission signal is received from the information processing device 17 is received. Is smaller than a preset time to (for example, a set time between 3 and 4 seconds).
[0048]
If the elapsed time T is less than the time to in step 106, the process returns to step 104.
[0049]
If the elapsed time T is equal to or longer than the time to in step 106, the process proceeds to step 107. That is, even if −αo <α <+ αo and not −βo <β <+ βo, the process proceeds to step 107 if the time to has elapsed.
[0050]
If it is determined in step 105 that −αo <α <+ αo and −βo <β <+ βo, the process proceeds to step 107.
[0051]
In step 107, the onboard information processing device 9 transmits the photographing permission signal to the still camera 2 and, at the same time, transmits the time at which the photographing permission signal was transmitted and the inclination angles α and β from the inclination angle detector 9 to the recording device 11. . The recording device 11 records the inclination angles α and β from the onboard information processing device 9.
[0052]
Then, in step 108, the still camera 2 having received the photographing permission signal drives the strobe light emitting device 3 and performs photographing in conjunction therewith.
[0053]
After the photographing is performed, the process waits for a photographing permission signal from the information processing device 17, and the process is restarted from step 104.
[0054]
Next, an image processing correction algorithm performed by the image processing apparatus 10 will be described. FIG. 5 is an explanatory diagram of the image processing correction algorithm.
[0055]
An image taken at a position where the optical axis of the still camera 2 equipped with the omnidirectional mirror (lens) 1 is parallel to the pipe axis of the sewer pipe 19 and deviated from the pipe axis indicates that the still camera 2 Since a portion near the inner wall surface is enlarged and a portion far from the inner wall surface is reduced, a distorted image is obtained as shown in FIG.
[0056]
Therefore, the distortion is corrected by compressing the image by the following algorithm.
[0057]
In FIG. 5, from the coordinates (Y, Z) of the hull 4 (that is, the optical axis of the still camera 2) calculated from the irradiation position of the laser pointer 8, the coordinates (Y, Z) indicating the position of the hull 4 are centered. The distance Ri to the inner wall of the sewer 19 in the clockwise direction from below vertically and in the direction of the angle θi can be calculated by equation (1).
[0058]
Ri = Z * cosθi-Y * sinθi + {(Y * sinθi-Z * cosθi) 2 - (Y 2 + Z 2 -0.25 * Dp 2)} 1/2 --- (1)
In the above formula (1), Dp indicates a tube diameter.
[0059]
Also, the field widths Z1i and Z2i shown in FIG. 5 at the distance Ri according to the equation (1) are given by the following equations (2) and (3).
[0060]
Z1i = Ri * tan θ1 --- (2)
Z2i = Ri * tan θ2 --- (3)
The image compression ratio ωi for each angle is calculated by the following formulas (4) and (5) based on the maximum value among the visual field widths Z1i and Z2i for each angle θi calculated by the above formulas (2) and (3). Compress the image.
[0061]
ω1i = Z1i / Z1max * 100 (%) ――― (4)
ω2i = Z2i / Z2max * 100 (%) ――― (5)
The distance h from the still camera 2 to the central axis of the pipe 19, the distance Hc to the water surface, and the water depth Lw can be calculated based on the coordinate position of the hull 4.
[0062]
In the case of still image shooting by the still camera 2, unlike moving images, the still image is intermittently shot from the moving hull 4, so that it may occur that an unphotographed area exists on the inner wall surface of the tube 19. Can be
[0063]
Therefore, in one embodiment of the present invention, the photographing intervals are determined so that photographing areas adjacent to each other partially overlap.
[0064]
FIG. 6 is a diagram illustrating an example of a method of determining a photographing interval according to an embodiment of the present invention.
[0065]
In FIG. 6, a photographing interval St is calculated from a photographing width of the still camera (corresponding to Z1 + Z2 in FIG. 5) and a predetermined minimum overlap area Amin with an adjacent photographing area. In FIG. 6, the photographing interval St is an interval from the position ta to td and an interval from the position tc to tf.
[0066]
Next, in one embodiment of the present invention, as described above, the shooting time is waited for the time to until the pitching angle α and the rolling angle β become close to 0 °. (Calculated from the time to and the speed of the hull 4).
[0067]
Therefore, the positions ta, tb, tc, and td are determined from the interval St and the interval P. Similarly, positions te, tf,... Are determined. As a result, the overlap area between the shooting area Ra shot at the position ta and the shooting area Rd shot at the position td becomes the minimum overlap area Amin, and the shooting area Rb shot at the position tb and the shooting area Rc shot at the position tc are different. Is the maximum overlap area Amax.
[0068]
Similarly, the overlap area between the shooting area Rc shot at the position tc and the shooting area Rf shot at the position tf is the minimum overlap area Amin, and the shooting area Rd shot at the position td and the shooting area Re shot at the position te Is the maximum overlap area Amax.
[0069]
If the initial position ta is determined, by controlling the photographing based on each of the calculated values, a photographed image having an overlapping region can be obtained, and the occurrence of an unphotographed region can be prevented.
[0070]
The overlapping area is desirably 30 to 40% of the photographing area.
[0071]
As described above, according to an embodiment of the present invention, the inner wall surface of a pipe is photographed at a timing at which the inclination of the hull becomes small while using a strobe light emitting means and a still image photographing means while preventing the occurrence of an unphotographed area. With such a configuration, it is possible to realize a tube inner wall surface image capturing apparatus which is capable of capturing a tube inner wall surface image that is clear and in which image distortion is suppressed.
[0072]
Therefore, it is possible to greatly reduce the amount of the wall surface photographed image and the amount of editing work involved with the image.
[0073]
Further, since the amount of information of the still image data is smaller than that of the moving image data, the transmission speed of the image information and the image processing speed can be increased.
[0074]
As a result, it is possible to reduce the time required for the evaluation of the inner wall surface state.
[0075]
Note that, in the above-described example, the correction by compressing the image has been described, but the distortion may be corrected by complementing the image.
[0076]
Further, in the above-described example, it has been described that the photographing is performed when the pitching angle α and the rolling angle β are each near 0 °. However, the photographing can be performed within ± 3 ° to 5 °.
[0077]
【The invention's effect】
Advantageous Effects of Invention According to the present invention, it is possible to realize a tube wall surface image photographing apparatus capable of capturing a tube wall surface image that is clear and image distortion is suppressed.
[0078]
That is, with the strobe light emitting device of the large capacity light source and the still camera that shoots at a high shutter speed, it is possible to obtain a clear image of the inner wall surface of the sewer with less blurring which affects the sway of the hull.
[0079]
Further, by photographing when the inclination of the hull is small by the inclination angle detector mounted on the hull, it is not necessary to correct the image caused by the inclination of the hull. Further, by measuring the position of the hull using a laser pointer, it is possible to correct image distortion due to deviation from the center of the tube axis.
[0080]
In addition, the amount of images captured on the wall surface can be greatly reduced, and the amount of editing work involved can be significantly reduced.
[0081]
Further, since the amount of information of still image data is smaller than that of moving image data, the transmission speed of image information and the image processing speed can be increased.
[0082]
As a result, it is possible to reduce the time required for the evaluation of the inner wall surface state.
[Brief description of the drawings]
FIG. 1 is an overall schematic configuration diagram of a tube inner wall surface image capturing apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an overall processing operation of image capturing according to an embodiment of the present invention.
FIG. 3 is a flowchart illustrating an image photographing algorithm.
FIG. 4 is a diagram showing an omnidirectional mirror image and a developed image.
FIG. 5 is an explanatory diagram of an image processing correction algorithm.
FIG. 6 is a diagram illustrating an example of an imaging interval determination method.
[Explanation of symbols]
Reference Signs List 1 omnidirectional mirror 2 still camera 3 strobe light emitting device 4 hull 5a, 5b wire 6a, 6b winch 7 tilt angle detector 8 laser pointer 9 onboard information processing device 10 image processing device 11 recording device 12a, 12b manhole 13 monitor 14 rotation detection Device 16 data input device 17 information processing device 18 cable 19 sewer

Claims (6)

An omnidirectional sensor, a still image photographing means for photographing an image obtained through the omnidirectional sensor, a floating body equipped with the omnidirectional sensor and the still image photographing means, and floating on a fluid, and a pipe inner wall surface image In the pipe wall image capturing device that captures
Posture state measuring means for measuring the posture state of the floating body,
Position detecting means for detecting the position of the floating body in the pipe axis direction,
When the posture state of the floating body measured by the posture state measuring means matches the set condition, and when the position of the floating body in the tube axis direction detected by the position detecting means matches the set condition, the still image photographing is performed. Photographing control means for photographing the inner wall surface image by the means,
A tube inner wall surface image capturing device, comprising: 2. The pipe inner wall surface image photographing device according to claim 1, further comprising: a pipe radial position detecting means mounted on the floating body for detecting a radial position of the floating body, wherein the floating body detected by the pipe radial position detecting means is provided. An inner wall surface image photographing apparatus for correcting an inner wall surface image photographed by the still image photographing means based on a position in a radial direction of the tube. 3. The pipe inner wall surface image capturing apparatus according to claim 1, wherein the floating body is pulled by a rope, and the rope is wound by a rope winding unit, whereby the floating body is pulled by the pipe axial direction. The above-mentioned position detecting means detects the position of the above-mentioned floating body in the direction of a pipe axis by measuring the number of rotations of the above-mentioned winding means, or measuring the scale written on a rope. 2. The apparatus according to claim 1, wherein the posture state is represented by a rolling angle and a pitching angle of the floating body. 3. 2. The apparatus according to claim 1, wherein the still image capturing unit captures a plurality of images in the tube axis direction, and adjacent images partially overlap each other. Pipe wall image capturing device. 2. The image capturing apparatus according to claim 1, wherein the still image capturing means includes a light emitting unit that emits light to a capturing target area.

Images