JPH0627676B2 - Steam leak detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vapor leak detection device that can be used for inspecting various plants, and more particularly to a vapor leak detection device that uses light as a detection means.

[Prior Art] The same applicant at the same time as the present invention, "steam leak detection device"
Applied for.

According to this, FIG. 5 is a schematic view of the light projecting portion and the light receiving portion of the vapor leak detection device. In the figure, (1) is a steam carrier pipe installed in the plant, (2) is a pipe (1)
Leaked vapor, (3) laser, (3-1) laser
Laser beam emitted from (3), laser (41)
(3) is the scattered light produced by the irradiation of steam (2),
(42) is the scattered light generated when the laser (3) hits the wall, (5) is the same scene taken from two windows, and the light from each window is imaged independently on one image sensor surface. Stereo mirrors, (51) and (52) are first and second windows for capturing respective screens, and (61) is a polarization direction parallel to the irradiation laser attached to the first window (51). The first analyzer has, (62) is the second window (52)
The second analyzer whose polarization direction is orthogonal to that of the irradiation laser attached to the laser, (71) and (72) are stereo mirrors (5)
A mirror installed inside, (8) is a television camera.

FIG. 6 is a diagram showing an example of an image obtained by the television camera (8). In the figure, (9) is an output image from the TV camera (8), (91) and (92) are left and right half screens of the image (9), and (10-1) and (10-2) are from the wall. Bright spots generated by scattered light, (11) bright spots generated by scattered light from vapor, (12) center line of screen, (13-1), (1
3-2) is a horizontal scanning line passing through the bright points (10-1) and (10-2), respectively, and (14-1) is a horizontal scanning line passing through the bright point (11).

FIG. 7 is a block diagram of a signal processing unit in a conventional vapor leak detection device. In the figure, (8) is a TV camera,
Reference numeral (15) is a low-pass filter, and (16) is a comparator, which binarizes a video signal obtained from the television camera (8). Reference numerals (17-1) and (17-2) denote first and second gate circuits, which distribute the video signal for each half cycle of the horizontal scanning cycle. (18) is a sync signal separation circuit, which separates only the sync signal from the video signal. Reference numeral (19) is a clock generation circuit for generating a clock signal, (20) is a gate control circuit for controlling the gate of the signal processing unit, (21-1) and (21-2) are first and second counters. Then, the number of horizontal scanning lines in which bright spots are generated in the left and right half screens of the image (9) is counted. Reference numeral (22) is a determination circuit, which includes first and second counters (21-
The judgment is made by comparing the count values of 1) and (21-2) with a predetermined value.

The conventional vapor leak detection device is configured as described above, and vapor leaked from the vapor carrying pipe (1) in which the laser beam (3-1) having the linear polarization characteristic is piped in the blunt.
When (2) is irradiated, scattered light (41) is generated from the vapor, and scattered light (42) is also generated from a wall, a pipe or the like irradiated by the laser beam (3-1) that has penetrated. These scattered lights are transmitted through the first and second windows (51) of the stereo mirror (5),
Taken from (52), mirrors (71) and (72) respectively
The images are independently formed on the image pickup device surface in the television camera (8) through the, and without overlapping each other. In the first window (51) of the stereo mirror (5), the laser beam (3-
The first analyzer (61) whose polarization direction is parallel to 1) and the second analyzer (62) whose polarization direction is orthogonal to the laser beam (3-1) are respectively in the second window (52). It is installed. On the other hand, the scattered light (41) from the vapor retains the linear polarization characteristic of the irradiation laser light, and the scattered light from the wall (42) does not retain the linear polarization characteristic of the irradiation laser light. It is described in Japanese Patent Application No. 61-38205, "Steam Leakage Detection Device", filed by K.K. As a result, the scattered light (41) from the vapor leak is the first of the stereo mirror (5).
Only the window (51) of the wall and the scattered light (42) from the wall
And through the second windows (51), (52) together. The image (9) obtained by the TV camera (8) has bright spots due to scattered light from the wall on both left and right screens with respect to the center line (12) of the screen.
The light spots are generated at the symmetrical positions of (91) and (92), respectively, and the bright spots due to the scattered light from the vapor are generated only on the left half screen (91). Noise is removed from the video signal from the TV camera (8) by the low-pass filter (15),
After being binarized by (16), it is input to the first and second gate circuits (17-1) and (17-2). On the other hand, the gate control circuit (20) controls the gate in the signal processing unit by using the synchronization signal generated by the synchronization signal separation circuit (18) and the clock signal generated by the clock generation circuit (19). First and second gate circuits (17-
The binarized video signals input to 1) and (17-2) are divided into sections corresponding to half screens on the left and right with the midpoint of one horizontal scanning time as a boundary by the gate control signal.
As a result, the binarized video signal corresponding to the left half screen is the first
Counter (21-1) and the binarized video signal corresponding to the right half screen is sent to the second counter (21-2). The first and second counters (21-1) and (21-2) respectively count the number of horizontal scanning lines in which a pulse has been generated in the input binarized video signal. After the same operation is repeatedly performed on one screen, the count result of each counter is sent to the determination circuit (22) and the count values are compared. The determination circuit (22), when the count value output from the two counters can be separated by a preset threshold value,
It is determined that steam leakage has occurred.

[Problems to be Solved by the Invention] In the conventional vapor leak detection device as described above, the number of horizontal scanning lines in which bright spots are generated is counted in each of the left and right half screens of the obtained image, and this scanning is performed. Since the steam leak is determined by comparing the number of lines with a predetermined value, there is a problem that only the presence or absence of steam leak can be detected, and the location of steam leak cannot be measured. .

The present invention has been made in order to solve such a problem, and an object thereof is to obtain a vapor leak detection device capable of three-dimensionally detecting the position where vapor leak occurs.

[Means for Solving Problems] A vapor leak detection apparatus according to the present invention includes a light projecting unit that irradiates a measurement target with light having a linear polarization characteristic, and a scene for the measurement target that receives light through a first analyzer. A first window and a second window having a deflection direction different from the first window.
And a light receiving means for independently forming an image of the scene captured from the first window and the second window on the same image pickup device surface, and a light receiving means. Circuit means for detecting the left-right symmetry of the generation position of the bright spots on the image obtained from the above, circuit means for detecting the generation position of the bright spots on the image, and steam from the output signals from both circuit means. The circuit means has a function of detecting this and a function of detecting the vapor leak generation position.

[Operation] According to the present invention, by installing the light receiving portion as in the upper part, it is possible to make the generation position of the scattered light on the laser beam correspond to the generation position of the bright spot on the screen. By detecting the bright spot due to the leak and detecting the generation position of the bright spot on the screen, it becomes possible to detect the presence or absence of the vapor leak and the distance to the generation position.

[Embodiment] FIG. 1 is a view showing an installation state of optical parts (light projecting part and light receiving part) showing an embodiment of a vapor leak detection device according to the present invention. In the figure, (23-1) and (23-2) are the first and second windows (51) and (5) of the stereo mirror (5), respectively.
2) has first and second fields of view, (24) is a tilt angle that the optical axis of the television camera (8) has with respect to the laser beam (3-1), and (25) is a stereo mirror seen from the side. The field of view of (5) and (8-1) are the central axes of the light receiving parts.

FIG. 2 is a diagram schematically showing the image forming operation according to the embodiment of the present invention. In the figure, (81) is an imaging lens, (2)
6-1-1) is the part corresponding to the left half screen on the image sensor surface,
(3-1-0) is the laser locus in the measurement field of view, (3-1-
1) is projection imaging of the laser locus (3-1-0) imaged on the image pickup device surface (26-1-1).

FIG. 3 is a diagram showing an output image from the television camera (8) according to the embodiment of the present invention. In the figure, (26-1)
Is the left half-screen of the obtained image, (26-2) is the right half-screen of the obtained screen, (10-1) and (10-2) are the bright spots generated by the scattered light from the wall, and (3 -1-1) and (3-1-2) are the loci indicated by the laser beam (3-1), (27-1) and (27-2) are pixel rows corresponding to one horizontal scan on the image, ( 28) is the number (N ₁ ) of horizontal scanning lines from the starting point of the image to the horizontal scanning line where a bright spot due to vapor leak occurs.

FIG. 4 is a block diagram of a signal processing unit according to an embodiment of the vapor leak detection device of the present invention. In the figure, reference numeral (15) is a comparator, which binarizes the video signal from the television camera (8). (18) is a sync signal separation circuit that separates the sync signal from the video signal, and (29) is a switching circuit that separates the binarized video signal into sections corresponding to the left and right half screens of the image, Send to two different video memories respectively. Reference numeral (30) is a control circuit for controlling the operation of each circuit in the signal processing unit, and reference numeral (31) is an address counter, which counts the position of the horizontal scanning line where the bright spot occurs in the image vertical direction. (32-1) and (32-2) are first and second video memories for storing video signals of left and right half screens of the obtained image, and (33) is a comparison circuit,
And the contents on the same horizontal scanning line stored in the second video memories (32-1) and (32-2) are compared. A determination circuit (34) detects the presence or absence of steam leakage from the output of the comparison circuit (33) and the output of the address counter (31) and measures the generation position of the bright spot due to the steam leakage.

In the steam leak detector configured as described above, a laser beam (3-1) emitted from a laser (3) to a steam (2) leaked from a steam carrying pipe in a plant and having a linear polarization characteristic When irradiated with, the vapor generates scattered light (41) and also scattered light (42) from walls, pipes, and the like. The light receiving part has the same structure, and when observing the above scene, a bright spot (11) due to vapor is generated from the TV camera (8) only on the left half screen (26-1) as shown in FIG. , Bright spots (10-1), (10-2) generated from walls, pipes, etc.
The images generated on the left and right half screens (26-1) and (26-2) are obtained. As shown in Fig. 1 (b), a stereo mirror (5)
The light receiving part is installed above the laser (3) so that the central axis of the laser and the irradiation laser beam (3-1) are on the same plane, and the central axis (8- The laser (3) and the television camera (8) are installed so that 1) intersects the irradiation laser beam (3-1) with a tilt angle (24). By determining the positional relationship between the light projecting portion and the light receiving portion in this way, the laser locus (3-1-0) in the measurement field of view is formed by the imaging lens (81) as schematically shown in FIG.
The left half screen equivalent part on the image sensor surface (26-1-1)
The projected image (3-1-1) formed above is a straight line extending in the diagonal direction of the left half screen equivalent portion (26-1-1) of the image sensor surface.

On the other hand, bright spots (10-1), (10-2) due to walls and pipes
Occurs on both left and right half screens (26-1) and (26-2) symmetrically with respect to the center line of the screen, and the bright spot (11) due to vapor is only on the left half screen (26-1). Occur. Further, as shown in FIG. 2, the irradiation laser beam (3-1) is displayed on the left half screen.
In (26-1), the locus (3-1-1) is taken, and in the right half screen (26-2), the locus (3-1-2) is taken. Any of the bright spots due to the scattered light from is generated on these trajectories. Also, the locus (3-
The length from the starting point (3-2-1) of 1-1) to the bright spot generation position corresponds to the distance from the TV camera (8) to the scattered light generation position. -1-1) and (3-1-2) are straight and extend diagonally, from the vertical position of the bright spot in the screen and from the TV camera (8) to the scattered light generation position. It becomes possible to correspond to the distance of. As shown in FIG. 4, the video signal output from the television camera (8) is binarized by the comparator (15) and input to the switching circuit (29). On the other hand, the control circuit (30) uses the synchronization signal and the clock signal obtained from the synchronization signal separation circuit (18) to control each circuit in the signal processing unit. The binarized video signal input to the switching circuit (29) is divided by the control signal from the control circuit (30) corresponding to both left and right half screens, and the video signal of the left half screen (26-1) is The video signal of the right half screen (26-2) is sent to the first video memory (32-1) and is sent to the second video memory (32-2). After the video signal of one screen is sent to the video memory, the signal on the same horizontal scanning line of each video memory is compared circuit.
(33) is compared sequentially, and if the positions of the bright spots on the left and right parts are symmetrical, the bright spots due to the scattered light from the wall, pipe, etc. are generated only on the left half screen, and due to the scattered light from the vapor. Judge as something. On the other hand, the address counter (31) counts the number of horizontal scanning lines compared by the comparison circuit (33) and sequentially outputs the counting result to the determination circuit (34).
The determination circuit (34) determines the presence / absence of steam leakage from the output of the comparison circuit (33) and extracts the counting result of the address counter (31) of the horizontal scanning line which is determined to have steam leakage. The distance to the vapor leakage generation position is detected by detecting the generation position on the screen where the bright spot due to is generated.

In the above embodiment, when detecting the position of vapor leak, attention was paid to the vertical generation position of the bright spots generated in the screen, but the same effect can be obtained by detecting the horizontal generation position. It is clear that it has been obtained.

Further, although the video memory having the capacity of one screen is used as the storage means of the image data in the above embodiment, a shift register having the capacity of one horizontal scanning may be used, and the left and right portions of the same horizontal scanning line may be used. By sequentially comparing the image data of 1) symmetrically with respect to the image center and detecting the position of the bright spot in the screen in the horizontal direction due to the steam leakage, the same effect as the above-described example can be obtained.

[Effects of the Invention] As described above, the present invention illuminates a measuring object with light having a linear polarization characteristic, a first window for receiving a scene of the measuring object through a first analyzer, and the scene. Has a second window for receiving light through a second analyzer having a deflection direction different from that of the first window, and a scene captured from the first window and the second window is captured on the same image sensor surface. Light receiving means for independently forming an image, circuit means for detecting left-right symmetry of the generation position of the bright spot on the image obtained from the light receiving means, and circuit for detecting the generation position of the bright spot on the image Means and circuit means having both the function of detecting the vapor leakage from the output signals from both the circuit means and the function of detecting the vapor leakage generation position, and the generation position of the bright spot on the screen and the irradiation laser beam And the position of scattered light at By setting the positional relationship between the light emitting part and the light receiving part so as to correspond to one, and by configuring the signal processing part so as to detect the bright spot due to vapor leak and to calculate the generation position in the image There is an effect that the position of steam leak can be detected.

[Brief description of drawings]

FIG. 1 is a diagram showing an installation state of optical parts (light emitting part and light receiving part) of a vapor leak detection device according to an embodiment of the present invention, and FIG. 2 is a schematic view of an image forming action of the optical part of FIG. FIG. 3 is an output image view from the television camera (8) of FIG. 1, FIG. 4 is a block diagram of a signal processing unit of the steam leak detection device of the present invention, and FIG. 5 is a projection of the steam leak detection device. FIG. 6 is an outline view of the light section and the light receiving section, FIG. 6 is an output image view obtained by the light receiving section of FIG. 5, and FIG. 7 is a block diagram of a conventional signal processing section. In the figure, (3) ... laser, (5) ... stereo mirror, (8) ... TV camera, (15) ... comparator,
(29) ... Switching circuit, (18) ... Synchronous signal separation circuit, (30) ... Control circuit, (31) ... Address counter, (32-1) and (32-2) ... First and The second video memory, (33) ... Comparison circuit, (34) ... Judgment circuit, (61) and (62) are first and second analyzers. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (4)

[Claims] 1. A light projecting unit for irradiating a measurement target with light having a linear polarization characteristic, a first window for receiving a scene of the measurement target through a first analyzer, and the scene different from the first window. Receiving light having a second window for receiving light through a second analyzer having a deflection direction, and independently forming images of the scenes captured from the first window and the second window on the same image sensor surface Means, circuit means for detecting the left-right symmetry of the generation position of the bright spot on the image obtained from the light receiving means, circuit means for detecting the generation position of the bright spot on the image, and both of the circuit means Circuit means having both the function of detecting the vapor leak from the output signal of the above and the function of detecting the vapor leak generation position, and the positions of the light projecting means and the light receiving means are the optical axis of the light projecting means and the optical axis of the light projecting means. Is the center axis of the light receiving means on the same plane? Steam leakage detection device, characterized in that said central axis to the optical axis is fixed so as to intersect at the front of said light projecting means. 2. The vapor leak detection device according to claim 1, wherein the circuit means for detecting the generation position of the bright spot on the image is an address counter. 3. The vapor leak detection device according to claim 1, wherein the light receiving means is a television camera. 4. The vapor leak detection device according to claim 1, wherein the light having the linear polarization characteristic is a laser.