JP2000180247A - Method and device for measuring liquid level - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level measuring device capable of easily measuring the water level of a high head-like a dam with high accuracy by using image processing and a camera. SOLUTION: A water gauge 10 combined with an inclined plate 9 is installed at a measurement place for measuring an object having a wide measuring range (a high head of about 20 m) like a dam. More detailed camera image is fetched by selecting the best scene by moving a camera 6 according to the water depth of the inclined plate 9 at every scene. The camera image to be input is image-processed with an image processor 1. This image processing detects the inflection point of a inclined figure part from the background of the camera image by a water level measurement means, determines it as water surface position coordinates in the image, and obtains the water level of a world coordinate system by converting the coordinates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level measuring method and apparatus for measuring the liquid level of dams, rivers, seas and the like, the liquid level of oil, solution and the like by non-contact image processing.

[0002]

2. Description of the Related Art The water level measures the distance from a reference horizontal plane to the surface of the water. Conventional methods for measuring the water level include floating a float on the water surface and measuring its position, A method of measuring water pressure has been put to practical use. Handbook of Mechanical Engineering (Revised 6th edition; Japan Society of Mechanical Engineers 197)
7; As described in Part 6, Measurement method, Chapter 7, 7.6 Measurement of liquid level), the liquid level is measured directly using a hook gauge or point gauge as the measurement of the displacement length. Others float a float on the liquid surface and mechanically measure the displacement of the float. Also,
Furthermore, as for the measurement of pressure, the deformation due to the pressure of the diaphragm attached to the bottom and side surfaces of the tank is mechanically and electrically detected, or the compressed air is inserted from the narrow end by inserting a thin tube into the liquid. There is one that ejects and measures the back pressure of the tubule. Further, recently, the present inventors have proposed a method for measuring the liquid level by image processing, in which an inclined plate is used or a scale plate is inclined so that the liquid surface position can be measured with an image (Japanese Patent Laid-Open No. Hei 7 (1994)). 333039, JP-A-8
14992, JP-A-8-145765 and others).

[0003]

The measurement of the water level of dams, rivers, the sea, etc., is severe in the climatic environment.
Maintenance management is not easy, and measurement by a non-contact method such as an image has been strongly demanded. However, even in image measurement, water is transparent, and it has been conventionally difficult to detect the water surface with a camera due to physical engineering characteristics such as specular reflection on the water surface. Also, in the method of detecting the water surface boundary by using the above-described inclined plate, even if a single inclined plate is used for a wide measurement range such as a dam, installation is not easy, It was difficult to accurately measure the water surface boundary by image processing.

It is an object of the present invention to measure a liquid level such as a dam with a large measuring range, such as a high head water level, by taking a camera image and performing image processing, thereby enabling non-contact measurement with high accuracy. To provide a liquid level measuring method and a measuring device.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a water mark having an inclined plate installed at an imaging position of a liquid surface position, and a posture control device installed at a position where an interface between the inclined plate and the liquid surface can be imaged. A camera image capturing device that can select a scene suitable for liquid level position imaging, and an inflection point of an inclined figure portion is detected from a background of a camera image input from the camera image capturing device, and the inflection point portion is imaged. This is achieved by providing an image processing apparatus having a liquid level measuring means for obtaining the liquid level in the world coordinate system by converting the coordinates of the liquid level in the image to the internal liquid level value coordinates.

The object of the present invention is to provide a water mark having an inclined plate installed at an imaging position of a liquid surface position, and a liquid surface position which is installed at a position where an image of a boundary between the inclined plate and the liquid surface can be taken. A camera image capturing device capable of selecting a scene suitable for imaging, and conversion information for capturing a reference point position and an elevation value on an image for each scene of a camera image, and setting coordinate conversion data of an image coordinate system and a world coordinate system. Setting means for detecting an inflection point of the inclined figure portion from the background of the camera image input from the camera image capturing device, and setting the inflection point portion as the liquid surface position coordinates in the image; This is achieved by providing an image processing apparatus having liquid level measuring means for obtaining a liquid level in the world coordinate system by extracting data necessary for coordinate conversion of the scene from the set coordinate conversion data and performing coordinate conversion. That.

Further, the above object is achieved by forming the inclined plate of the water mark into a structure in which a plurality of inclined plates or inclined figures are vertically arranged in multiple stages.

The object of the present invention is to provide the image processing apparatus, wherein the camera posture, focus, and zoom of each scene are set for each preset number corresponding to each of a plurality of measurement scenes obtained by equally dividing the measured height of the camera. Camera scene setting control means for setting, and measurement scene detection means for transmitting a preset number corresponding to each scene to the control means of the camera and changing the camera scene to search for an optimal scene for capturing a camera image. Achieved by

[0009] By using the above means, a vertical water mark and an inclined plate are arranged side by side at an imaging position of a liquid surface position, and a scene at a boundary portion between the inclined plate and the liquid surface is imaged and captured by a camera. In this camera image, a reflection image or a refraction image appears due to the inclined plate, and the liquid level can be easily detected with high accuracy. The captured camera image is subjected to image processing to detect an inflection point of the inclined figure portion due to the inclined plate from the background of the camera image, the inflection point portion is used as a liquid surface position coordinate in the image, and this is converted into a world coordinate. The liquid level of the system can be determined.

In the coordinate conversion, a reference point position and an elevation value on an image of each scene of a camera image are fetched, coordinate conversion data of an image coordinate system and a world coordinate system are set, and the coordinate conversion data of the corresponding scene is obtained from the coordinate conversion data. The data necessary for the coordinate conversion is extracted and the coordinates of the liquid surface position in the image are converted.

A plurality of the inclined plates are arranged in a plurality of stages, and a plurality of measurement scenes are equally set at the height to be measured by the camera. The measurement of a liquid level having a crack can be easily performed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 illustrates the overall structure of a dam water level measuring device according to an embodiment of the present invention. The device constantly measures and monitors the water surface in the upstream part of the reservoir of the dam.

In the figure, reference numeral 7 denotes a concrete wall at the upstream of the dam, in which water is stored. Monitoring this water level is, of course, a necessary part of dam management. In the upstream part of the concrete wall 7, a water mark 10 with a scale and a water mark 9 of a slope plate (hereinafter referred to as a slope plate) are installed. Here, the inclined plate 9 is a plate in which an inclined pattern is drawn, one in which one inclined plate or a plurality of inclined plates are attached to the concrete wall 7 one by one, or one in which the inclined plate is attached to a vertically erected frame. Etc. are used. In order to perform image processing at night, it is necessary to use a high-sensitivity camera and install an illumination 12 on the dam concrete wall 7. On the water surface in the dam, floating objects flow from upstream, so that a fence 19 using a net and a float is provided so that these floating objects do not hinder image processing. The camera image capturing device 6 is installed at a position where images of the water mark 10 and the inclined plate 9 can be captured. The captured camera image is transmitted via the camera control box 5 to a measuring device installed indoors. As a device that analyzes camera images and measures water levels,
A camera signal receiving device 4, a camera control means 2, a camera console 3, an image processing device 1, and the like are installed indoors. Although these devices increase or decrease depending on the situation, basically, at least an image processing device is sufficient as long as the environment allows input of a video signal.

FIG. 2 shows the principle of detecting a water surface which is transparent and has specular reflection characteristics by image processing. FIG. 2A shows a state where the reflection shadow 102 of the inclined plate 101 is specularly reflected on the water surface. In the case of a water mark installed vertically, this reflected shadow becomes an obstacle and the water surface cannot be detected.
In the case of the inclined plate, the features on the image appear at the water surface boundary portion between the inclined plate 101 and the reflection shadow 102 in the water surface portions 104 and 105, and it can be seen that the water surface detection by the image is easy. FIG. 2B shows the case where the transparency of water is good. The refraction image 103 of the inclined plate below the water surface is clearly seen from above the water surface. In the case of a water mark installed vertically, this refraction image becomes an obstacle and the water surface cannot be detected. However, in the case of an inclined plate, the features on the image appear at the water surface boundary portions 104 and 105. It appears that the water surface detection by the image is easy. As described above, in the vertical water mark, the inclined plate facilitates the detection of the water surface by using the reflection image and the refraction image which are obstacles to the detection of the water surface. FIG. 2C shows a case where there is a wave on the water surface, in which neither the reflection image nor the refraction image appears on the water surface, and the water surface can be detected even with a vertical water mark. Of course, in the case of the inclined plate, the water surface can be detected without any problem.

If there is a problem in installation or a problem in image processing with one inclined plate, a multi-stage inclined plate as shown in FIG. 3 is used. FIG. 3A shows the frame 110-1.
And a plurality of inclined plates 110-2 attached thereto for measuring water level. It is convenient for installation in general rivers. FIG. 3B shows the frame 120-1.
And a plurality of inclined plates 120-2 attached in a V shape. This is also convenient for installation in general rivers. FIG. 3 (c)
Is an inclined plate 9 for measuring water level, which is composed of a back plate 9-1 and a plurality of pictures 9-2 of inclined plates. This is suitable when a mounting surface such as a concrete wall of a dam can be secured. The back plate 9-1 is black, and the slanted picture portion 9-2 is white.

FIG. 4 shows an example of a measuring component device according to an embodiment of the present invention. The camera image capturing device 6 includes a camera 6-
1, consisting of a pan head 6-2, etc. The image processing device 1
CPU 1-1, main memory 1-2, image processor 1-6, auxiliary storage 1-7, communication means 1-8, display 1-5, monitor T
V1-9, keyboard 1-3, mouse 1- for operator operation
It is composed of 4 magnitudes. Further, the number of peripheral devices of the image processing apparatus varies depending on the situation, but basically, it is sufficient that the peripheral devices can execute the basic processing of the present invention. The image processing result can be easily monitored by connecting the monitor TV 13 to the output of the image processing apparatus 1. The image processor 1-6 has a built-in or external image scale 1-10.

FIG. 5 is a detailed explanatory diagram of the functional configuration of the water level measuring device according to one embodiment of the present invention. In order to operate the present apparatus, first, the operator 14 needs to activate the offline processing means 16 on the guidance screen 15 and perform necessary preparation processing. When the preparation processing is completed, the online processing means 17 is activated to start the water level measurement.
These operations are performed by the operator 14 by the monitor TV 1-9,
This is done using the keyboard 1-3 or mouse 1-4. The camera control means 2 is for controlling the attitude of the camera, adjusting the focus, changing the zoom, and the like.

The offline processing means 16 includes a preset number setting means 16-1, a camera scene setting control means 16-2, a camera control information storage means 16-3, a conversion information setting means for an image coordinate system and a world coordinate system for each scene. It consists of 16-4 functions. The online processing means 17 is a measurement scene detection means
17-1, input check means 17-2, scene switching means 17-
3. It is composed of a water level measuring means 17-4, a measurement result output means 17-5 and the like. The camera scene setting information is stored in the camera scene setting information storage unit 18-1, the coordinate system conversion information is stored in the coordinate conversion data storage unit 18-2, and the preset number of the image being processed is stored in the current preset number 18-3. It shall be.

FIG. 6 shows a specific example of the vertical type water mark 10 used in the present invention. Main unit 10-1, scale 10-2, display number 10
-3, a sub-reference position 10-4, and a reference scale 10-5 are formed. 1
1 is a number indicating an altitude value. FIG. 7 shows a schematic specification of the inclined plate 9 suitable for a dam. The back plate 9-1 is coated with black matte paint. The inclined board picture 9-2 is coated with white matte paint. As shown in FIG. 8, the vertical water mark 10 and the inclined plate 9 are arranged side by side and installed close to each other. Thus, the water level can be easily obtained from the relationship between the water surface detected by the inclined plate 9 and the scale of the vertical water gauge 10. The camera has a structure that allows the user to swing his head up and down, and can perform image processing by selecting a scene suitable for measuring the current water surface, such as scene number 1 and scene number 2. FIG. 9 is an example in which the measured height of the dam into which the water marks 9 and 10 are inserted is equally divided to set a plurality of measurement scenes (scene numbers 1, 2,..., 12). A swing angle of the camera is set for each scene number.

FIG. 10 shows the guidance screen 15 of the offline processing means 16. Preparation processing for water level measurement is performed according to this guidance. The description will be made in the order of execution. If the cursor is pressed on the preset number input section 15-2, the color of this part changes, and the preset number setting means 16-1 allows the preset number 15-10 to be input. Upon completion of the input, the flow shifts to the next process 15-3. Here, the camera is operated, and the measurement scene is determined by the camera scene setting control means 16-2. Use the functions such as operation 15-11 to move the camera up, down, left and right, zoom setting 15-12, and focus adjustment 15-13. Upon completion, when the user presses the complete button 15-14, all the set values set by the camera control information storage means 16-3 are stored in association with the preset numbers. Next, coordinate conversion setting 15-4
Is performed using the camera screen 15-7. Cursor on screen
The first reference point 15-16 and the second reference point 15-17 are determined by operating the cursor 15-15 up and down on the cursor display 15-15. Next, the process proceeds to the reference water level setting 15-5. Upper water level 15-21 and lower water level 15-22
Enter This operation is repeatedly performed for all scenes.

The principle that the image coordinate system and world coordinate system conversion information setting means 16-4 sets coordinate conversion data for each scene by the determination of the first reference point 15-16 and the second reference point 15-17. Will be described with reference to FIG. When the cursor is placed on the first reference point, the coordinates Y1 from the image origin position to the first reference point position in the y-axis direction are stored. At the same time, the altitude y1 between the ground reference point and the first reference point is input and stored. Next, when the cursor is moved to the second reference point, the coordinate Y2 from the image origin to the second reference point is stored, and at the same time, the coordinate value y2 between the ground reference point and the second reference point is input and stored. Let it. The conversion information setting means calculates a coordinate conversion coefficient ε = ABS ((y1-y2) / (Y1-Y2)) from the input data,
BS: Absolute value is calculated. From this, the image origin elevation value Orgn = y1 + Y1 · ε (or Orgn = y2 + Y2 · ε) is calculated. This process is performed for each scene (i) by changing the scene of the camera image.

FIG. 12 shows a camera scene setting information storage means.
FIG. 13 shows an example of the storage data of the coordinate conversion data storage means 18-2, and FIG. 14 shows an example of the storage data of the reference water level information.

FIG. 15 is a flowchart for explaining the operation of the apparatus according to the present embodiment. When the power is turned on, an initial task is started (box A). In the initial task, system-wide initial settings are executed (box B). Offline processing (box G) or online processing (box E) is selected by processing selection (boxes C and D).

FIG. 16 shows a flowchart of the offline processing. When the off-line process is selected, first, a guidance screen is displayed (box G100). The following processing is executed on this guidance screen. Preset number input (Box G200, 300), camera scene setting (Box G400, 500), coordinate conversion setting (Box G600, 700),
The reference water level setting (boxes G800, 900) is performed sequentially. The above is repeated for all scenes (box G100
0).

FIG. 17 illustrates the process of inputting a preset number (box G300). The preset number is fetched and the input preset number is displayed on the camera scene. Then, the input preset number is stored and used for the following processing.

FIG. 18 shows a camera scene setting (box G).
The processing of (500) will be described, and an operator input operation will be performed (box G500-10), and the scene setting will be set by adjusting the camera direction up, down, left and right (box G500-20). Adjust the zoom settings so that the field of view is appropriate (Box G
500-30). Adjust focus settings for optimal focus
(Box G500-40). Upon completion, the set values are stored in the storage means (G500-50). FIG. 19 shows the process of the coordinate conversion setting (box G700), in which the operator performs an input operation (box G700-10), adjusts the cursor on the cursor display to the reference point (box G700-20), and sets the first reference. Read the position indicated by the cursor as a point and
And the altitude value of the first reference point is input (box G700-30). Next, the position indicated by the cursor is read as the second reference point, which is used as the coordinates (on the screen) of the second reference point, and the altitude value of the second reference point is input (box G700-40). After the two points have been input as described above, the coordinate conversion coefficient ε and the image origin elevation value Orgn are calculated by the method described with reference to FIG. 11, and the obtained data is stored (box G700-50).

FIG. 20 shows a reference water level setting (box G90).
0), and perform an operator input operation (box G900-1).
0), the upper limit value is fetched by setting the upper limit position (box G900-20). Next, the lower limit is set by setting the lower limit position (G900-30). After the input, the upper and lower limit values are stored. Confirm by screen display (Box G900-50).

FIG. 21 shows an example of an image 19 displayed on the online monitor TV 13 as a result of image processing at the time of online execution. A water level measurement result 19-4, a water level reference 19-3, and the like are displayed superimposed on a camera image (a water mark 19-1, an inclined plate 19-2, and a water surface 19-5). By using this image for monitoring, the water level can be managed with high reliability. FIG. 22 shows information detected by the measurement scene detection means 17-1 and stored in the current preset number management means 18-3, and shows a guideline for switching to an adjacent scene according to the position of the water surface in the scene being measured. Should be set in this way. At the time of online processing, as the water level measurement result by the water level measurement unit 17-4, data as shown in FIG. 24 is stored by the storage unit 18-6. The water level measurement is
Instantaneous values are stored with time information attached.

FIG. 25 shows a flow chart of the online processing. First, a scene for measuring the water level is searched (box E100). When an optimal scene for measurement is found by the measurement scene detection unit 17-1, the preset number of the camera concerned is stored in the preset number management unit 18-3. After that, the camera image is captured (Box E200), and the water level measurement unit 1
Perform water level measurement (Box E600) using 7-4. The camera image check (box E400) by the input scene check unit 17-2 is a process for determining a change time for changing the camera scene in response to a change in the water surface. When a scene change occurs, a scene switching process is executed by the scene switching means 17-3 (box E50).
0). The switching of the scene is performed according to the scene switching management table 18-5 shown in FIG. In the reference water level check process (box E700), an alarm is output when a predetermined reference water level is exceeded (box E800).

FIG. 26 illustrates the processing (box E100) by the measurement scene detecting means 17-1. The preset number is transmitted from the image processing side to the camera control means 2 from PNO = 1 (box E100-20). The camera image is captured (Box E100-30) while controlling the camera, and the presence or absence of the water surface is checked by image analysis (Box E100-40). If not, the preset number is sequentially changed and transmitted (Box E10).
0-50), while changing the camera scene sequentially, processing to obtain a scene that captures the water surface well. Once the best scene for measurement is determined, save the preset number
(Box E100-70). If an optimum scene is not found, an abnormal process is performed (box E100-60).

FIG. 27 shows a procedure for always performing image processing of an optimal scene corresponding to a change in the water surface in the procedure of the camera image check processing (box E400) by the input scene check means 17-2. The water surface area on the screen is detected (Box E400-10), and it is checked whether the water surface exceeds the upper limit area of the screen (Box E400-20). -1 (box E400-40). Check that the water surface does not exceed the lower area of the screen (Box E400-3)
0) If the lower limit is exceeded, the preset number is set to the current preset number + 1 (box E400-50). By changing the preset number, the best scene is selected.

FIG. 28 shows an image water surface position coordinate (Yimage) from the image origin to the water surface in the vertical water mark direction (y-axis) in the procedure of the water level measurement process (box E600) by the water level measurement means 17-4. (Box E600-10), coordinate conversion is performed (Box E600-20), and the water level Wlevel is obtained.

FIG. 29 shows the detection of the water surface position (box E60).
This describes the procedure of (0-10), in which the inclined figure part 101 is extracted from the background of the input image (box E600-10-1), and the inflection point 104 of the inclined figure part 101 is detected (box E60).
0-10-2). The Y coordinate of the inflection point 104 from the image origin is defined as the water surface position coordinate (Yimage) in the image (box E
600-10-3).

FIG. 30 shows the coordinates of the water surface position (Yimag
This explains the procedure of coordinate conversion (box E600-20) for obtaining a water level from e). Coefficients (coordinates) required for coordinate conversion corresponding to the corresponding preset number (i) are stored from the coordinate conversion data storage means 18-2. Conversion coefficient ε (i), image origin elevation value
Orgn (i)) (Box E600-20-1). Next, the coordinates are converted by the equation: Wlevel = Orgn + Yimage · ε to obtain the water level Wlevel in the world coordinate system (box E600-20-2).

Although the present invention has been described with reference to the case where the water level stored in a dam is measured, the present invention is not limited to measuring the water level of a dam, river, lake, sea, etc., but also measuring the liquid level of oil, solution, debris flow, etc.
It can be applied to other surface level measurement and the like.

[0037]

As described above, according to the present invention, non-contact type image processing can be applied to water level measurement and liquid level measurement of a high head such as a dam, and extremely accurate measurement can be performed.

[Brief description of the drawings]

FIG. 1 is an overall view of an apparatus according to an embodiment of the present invention.

FIG. 2 is a view for explaining the principle of water surface detection by an inclined plate and an image processing apparatus.

FIG. 3 is an exemplary view of an inclined plate having a multi-stage structure.

FIG. 4 is a configuration diagram of a water level measurement device according to an embodiment of the present invention.

FIG. 5 is a functional configuration diagram of a water level measuring device according to an embodiment of the present invention.

FIG. 6 is a structural diagram of a vertical scale water mark.

FIG. 7 is a structural diagram of a multi-step inclined plate.

FIG. 8 is an explanatory diagram of scene division by a water mark measurement unit.

FIG. 9 is a diagram illustrating the relationship between scene division and camera posture.

FIG. 10 is a guidance screen diagram of offline processing.

FIG. 11 is an explanatory diagram of coordinate conversion information setting processing.

FIG. 12 is a diagram illustrating data stored in a camera scene setting information storage unit.

FIG. 13 is a storage data diagram of a coordinate conversion data storage unit.

FIG. 14 is a diagram illustrating data stored in a management storage unit of a current preset number.

FIG. 15 is a processing procedure diagram when starting up the entire system.

FIG. 16 is a flowchart of a processing procedure of an offline processing unit.

FIG. 17 is a flowchart of a preset number capturing processing procedure.

FIG. 18 is a flowchart of a camera scene setting processing procedure.

FIG. 19 is a flowchart of a coordinate conversion setting processing procedure.

FIG. 20 is a flowchart of a reference water level setting processing procedure.

FIG. 21 is a diagram showing an image processing result screen during online processing.

FIG. 22 is a storage data diagram of a current preset number management unit.

FIG. 23 is a diagram illustrating data stored in a scene switching area management unit.

FIG. 24 is a storage data diagram of a water level measurement data management unit.

FIG. 25 is a flowchart of a processing procedure of an online processing unit.

FIG. 26 is a flowchart of a measurement scene detection processing procedure.

FIG. 27 is a flowchart of a camera image check processing procedure.

FIG. 28 is a flowchart of a water level measurement processing procedure.

FIG. 29 is a flowchart of a water surface detection processing procedure.

FIG. 30 is a flowchart of a water level calculation processing procedure by coordinate conversion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image processing apparatus, 2 ... Camera control means, 3 ... Camera console, 4 ... Transmission / reception apparatus, 5 ... Control box, 6 ... Camera image capturing apparatus, 7 ... Concrete wall, 8, 9 ... Inclined plate, 10 ...
Water mark, 11 elevation value, 12 lighting, 13 online monitor TV, 14 operator, 15 guidance screen, 16 offline processing means, 17 online processing means, 19 fence, 1-1 CPU, 1-2… Main memory,
1-3… keyboard, 1-4… mouse, 1-5… display, 1
-6: Image processor, 1-7: Auxiliary storage device, 1-8: Communication means, 1-9: Monitor TV, 1-10: Image memory, 6-1: Camera, 6-2: Head, 16- 1 ... Preset number setting means, 16-2
... Camera scene setting control means, 16-3 ... Camera control information storage means, 16-4 ... Conversion information setting means, 17-1 ... Measurement scene detection means, 17-2 ... Input scene check means, 17-3 ... Scene switching Means, 17-4: water level measurement means, 17-5: measurement result output means, 18-1: camera scene setting information storage means, 18-2: coordinate conversion data storage means, 18-3: current preset number storage means, 18-4: Reference water level information storage means, 18-5: Scene switching management table, 18-6: Water level measurement value storage means, 101: Slant figure part, 102: Reflected shadow, 103: Refracted image, 104, 1
05 ... inflection point.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeo Kasai 5-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside the Omika Plant, Hitachi, Ltd. (72) Inventor Ken Saito 4-6-6 Kanda Surugadai, Chiyoda-ku, Tokyo Address F-term in Hitachi, Ltd. Machinery & Electrical Division (reference) 2F014 FA04 GA01 5B057 CD20 DA07 DB02 DC07

Claims (4)

[Claims] 1. A water mark having an inclined plate is installed at an imaging position of a liquid surface position, a scene at a boundary between the inclined plate and the liquid surface is imaged and captured by a camera, and an inclined figure is extracted from a background of the image captured by the camera. Detecting the inflection point of the part, setting the inflection point portion as the liquid level position coordinate in the image, and obtaining the liquid level in the world coordinate system by performing coordinate transformation on the liquid level position coordinate in the image. Measurement method. 2. A water mark having a sloping plate is installed at a liquid surface position imaging location, a scene of a boundary portion between the sloping plate and the liquid surface is imaged and captured by a camera, and the camera-captured image is taken for each scene. The reference point position on the image and its elevation value are taken in, the coordinate conversion data of the image coordinate system and the world coordinate system are set, and the inflection point of the inclined figure portion is detected from the background of the image captured by the camera, and the inflection point portion is detected. A liquid level measurement method comprising: obtaining a liquid level in a world coordinate system by using a liquid level position coordinate in an image and performing coordinate conversion on the liquid level position coordinate in the image using the coordinate conversion data of the scene. 3. A liquid level measuring apparatus for measuring a liquid level by performing image processing by imaging a liquid level position, comprising: a water mark having an inclined plate installed at a liquid level position imaging position; A camera image capturing device installed at a position where a boundary portion between the camera image can be captured and a scene suitable for liquid surface position capturing by posture control, and a tilted figure portion from the background of the camera image input from the camera image capturing device. An image processing apparatus having a liquid level measuring means for detecting an inflection point, setting the inflection point portion as a liquid level position coordinate in an image, and transforming the liquid level position coordinate in the image to obtain a liquid level in a world coordinate system. And a liquid level measuring device. 4. A liquid level measuring device for measuring a liquid level by performing image processing by imaging a liquid level position, wherein a water mark having an inclined plate installed at a liquid level position imaging position; Camera image capture device installed at a position where the boundary between the camera and the camera can be imaged and a scene suitable for liquid surface position imaging can be selected by attitude control, and a reference point position and an elevation of the reference point on the image of each scene of the camera image Conversion information setting means for taking values and setting coordinate conversion data of the image coordinate system and the world coordinate system; detecting an inflection point of the inclined figure portion from the background of the camera image input from the camera image acquisition device; The point portion is defined as the liquid level position coordinate in the image, and the liquid level position coordinate in the image is obtained by extracting data necessary for the coordinate conversion of the corresponding scene from the set coordinate conversion data and performing coordinate conversion, thereby setting the liquid level in the world coordinate system. Liquid A liquid level measuring device, comprising: an image processing device having a position measuring means.