JP2006258575A - Method and system for measuring flow velocity of river and method and system for measuring river flow rate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To establish highly accurate methods and systems for measuring flow velocities of rivers and river flow rates. <P>SOLUTION: A water surface of the overall length of the width of a river is divided into a plurality and imaged by a plurality of imaging means 3 for remote monitoring, and the water level of the river to be imaged is measured by a water level measuring means 23. Image signals by the imaging means 3 and water level data by the water level measuring means 23 are transmitted to a control unit 17. At the control unit 17, flow velocities in an area to be measured of a plurality of previously set traverse line segments in the width direction of the river are computed by analyzing the image signals by a concentration gradient method, and the cross-sectional area of the river in the width direction of the river is computed on the basis of the water level data. On the basis of both the cross-sectional area of the river and a flow velocity value of each traverse line segment, a highly accurate total quantity of flow is computed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a river flow velocity measurement method, a river flow rate measurement method, a river flow velocity measurement system, and a river flow rate measurement system, and in particular, a plurality of CCD cameras and an optical flow device that performs image analysis processing are installed, and each observation data For example, a river flow rate measurement method, a river flow rate measurement method, a river flow rate measurement system, and a river flow rate measurement system for comprehensively measuring the flow rate and flow rate of a medium-sized river having a river width of about 100 m to 200 m. .

  Hydrological data in rivers is the basic information that forms the basis of river planning and management. In particular, data such as water level and discharge during flooding are indispensable as basic data for various flood control plans.

  The water level and rainfall of rivers are automatically collected by various measuring devices and automatically collected by a telemeter observation device, etc., and labor saving and efficiency of observation are achieved. However, in river flow observation, there are many human factors in the conventional observation method, so there is a risk that the measurement at the flood peak may be missed, leaving problems in the reliability of the measurement results. .

  For example, conventionally, as a method of measuring the river flow rate, it is measured with a flow meter installed at a predetermined place in the basin, or as a commonly used method, the flow cross-sectional area and the average flow velocity at a certain point in time are measured. Calculated as the product of both. In the latter case, the flow velocity measurement method includes a method using a portable velocimeter directly thrown into water and a method of measuring the flow of the float by visual observation or the like. These methods only measure a portion of the entire basin. Moreover, on the surface of the water flow flowing down the river at a certain speed, there are swirls, reverses, and meandering flows for each part, making it difficult to grasp the speed of the entire river cross-sectional area.

  As described above, the conventional river flow measurement method is not easy to improve the accuracy compared with other hydrological observation methods such as river water level and rainfall, so establishment of a new flow measurement method is required. .

  Conventionally, the remote monitoring camera is used to capture a debris flow that flows in a river with a remote monitoring camera installed at the danger site. The video signal captured in step 1 is recorded and stored in a video recorder, and the video of this video recorder is subjected to image analysis processing using a video processing package and a water flow analysis package program. A method for obtaining the speed has been developed (see, for example, Patent Document 1).

Conventionally, by applying the image analysis processing method described in Patent Document 1 above, one CCD camera is artificially installed at a specific location with a river width, the image of the river surface is analyzed, and the flow rate is measured. is doing. Based on the measured flow rate, the flow rate of the entire river width is converted in relation to the area captured by the CCD camera and the river width, and this converted value is regarded as the total flow rate of the river.
Japanese Patent No. 3081872

  By the way, in the conventional river flow measurement method, not only the method using a velocimeter in a specific basin, the method using a portable velocimeter and a float, but also a river flow measurement method based on image processing captured by a CCD camera is accurate. There was a problem that the flow rate data could not be obtained.

  The present invention has been made to solve the above-described problems.

  In the river flow velocity measuring method of the present invention, a plurality of remote monitoring imaging means divides and captures the entire water surface in the width direction of the river and transmits an image signal from the imaging means to a control device. By analyzing the image signal by the density gradient method, the flow velocity of the measurement area for a plurality of survey lines in the river width direction set in advance is calculated.

  The river flow rate measuring method of the present invention is obtained by dividing and imaging the water surface of the entire length in the width direction of the river by a plurality of remote monitoring imaging means, measuring the water level of the river to be imaged by the water level measuring means, and the imaging means And the water level data by the water level measuring means are transmitted to a control device, and the control device analyzes the image signal by a concentration gradient method to measure the measurement areas for a plurality of line segments in the river width direction set in advance. The flow rate of the river is calculated, the river cross-sectional area in the width direction of the river is calculated from the water level data, and the total flow rate is calculated from the river cross-sectional area and the flow velocity value for each of the survey lines. .

  The river flow measurement method according to the present invention is the river flow measurement method, wherein in the river flow measurement method, when the water level data exceeds a preset water level reference value, image recording from the remote monitoring imaging means is started, and from the water level reference value It is preferable to stop the image recording when it becomes low.

The river flow velocity measurement system according to the present invention has a plurality of remote monitoring imaging means arranged in the river to divide the entire water surface in the width direction of the river into a plurality of images.
A control device comprising a river flow velocity calculation unit for analyzing the image signal transmitted from the remote monitoring imaging means by a concentration gradient method and calculating flow velocity in a measurement area for a plurality of measurement lines in a predetermined river width direction. It is characterized by being provided.

The river flow rate measuring system of the present invention is arranged with one or more remote monitoring imaging means in the river to divide the water surface of the entire length in the width direction of the river into one or a plurality of images,
Providing a water level measuring means for measuring the water level of the river to be imaged;
A river flow velocity calculation unit for analyzing the image signal transmitted from the remote monitoring imaging means by a concentration gradient method and calculating a flow velocity in a measurement area for a plurality of measurement lines in a predetermined river width direction;
A river cross-sectional area calculation unit for calculating a river cross-sectional area in the width direction of the river from the water level data transmitted from the water level measurement means, a river cross-sectional area by the river cross-sectional area calculation unit, and a line for each measurement line by the river flow velocity calculation unit And a river flow rate calculation unit for calculating the total flow rate from the flow velocity value of the control unit.

  In the river flow measurement system according to the present invention, in the river flow measurement system, the control device includes recording means for recording the image signal, and starts recording when the water level data exceeds a preset water level reference value. It is preferable to include a recording control unit that provides the recording unit with a command and a command to stop recording when the water level becomes lower than the water level reference value.

  As can be understood from the means for solving the above-described problems, according to the present invention, a non-contact measurement method for analyzing a photographed image by a plurality of remote monitoring imaging means, wherein the water level, flow velocity, and flow rate are determined. Monitor automatically and in real time. In addition, remote observation can be performed from the image of the imaging means for remote monitoring transmitted to the office by the optical fiber laid for river management, and it can be expected as one of the effective utilization of the optical fiber communication network. Measurements do not require a float, do not require installation of equipment in the water, and can be observed even with high flow rates and large quantities of falling objects. In addition, unmanned observation enables safety and labor saving, and can reduce the cost of observation work.

  Furthermore, it is possible to analyze a complex flow velocity distribution and measure even when the water flow is not correct, such as a curved portion of a river. In addition, post-analysis / verification by the recording means is possible. Further, since the recording means starts recording when the water level data exceeds a preset water level reference value, it is economical.

  In addition, since the surface flow velocity distribution can be grasped by video, it can be measured over a wide range with a single remote monitoring imaging means, and the analysis results of multiple remote monitoring imaging means can be integrated, enabling more accurate observations. Is possible.

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

  Referring to FIG. 1, a river flow measurement system 1 according to this embodiment is directed to, for example, an ITV camera 3 (CCD camera) as a remote monitoring imaging means, for example, on a river surface or a sabo dam as a measurement target. For example, a plurality of the ITV cameras 3 are arranged on a bridge 5 in a river, for example. Although only one ITV camera 3 is shown in FIG. 1, for example, in the case of a medium-sized river having a river width of about 100 m to 200 m, a plurality of ITV cameras 3 are arranged. Video information of the flow velocity measurement area captured by the plurality of ITV cameras 3 is transmitted as an image signal from the optical termination 9 of the observation station 7 to the optical termination 15 of the observation station 13 via the optical fiber cable 11.

  The image signal is transmitted from the ITV control device 19 in the control device 17 to, for example, an optical flow processing device 21 (hereinafter referred to as “OF processing device” for short) as an image analysis processing device. The velocity distribution of the fluid surface is calculated by moving image analysis processing. The system so far is also a river flow velocity measuring system according to the embodiment of the present invention, which is a so-called non-contact type river flow velocity measuring apparatus.

  Further, water level data of, for example, a water level gauge 23 as a water level measuring means installed in the river to be measured is converted into a signal by the water level converter 25 of the observation station 7, and an optical fiber cable is connected from the optical termination 9 by the optical transmission device 27. 11 is transmitted to the optical termination 15 of the observation station 13 and input to the OF processing device 21 by the optical transmission device 29. Moreover, river crossing survey data is input to the OF processing device 21 in advance. Therefore, the OF processing device 21 calculates the river cross-sectional area from the above-mentioned water level data and river cross-sectional survey data to the river surface, and the average flow velocity for each survey line over the entire river width by the river cross-sectional area and the river flow velocity measurement system. The total flow of the river is automatically calculated from the above.

  The river flow measurement system 1 will be described in more detail. In FIG. 1, only one ITV camera 3 is shown, but in this embodiment, a case where four ITV cameras 3 are arranged will be described as an example.

  Referring to FIG. 2, a river cross section (bed line) and a water surface of the entire width of a river to be measured are illustrated, and the river width is changed to first to fourth flow velocity measurement areas 31A, 31B, 31C, and 31D. A total of four first to fourth ITV cameras 3A, 3B, 3C, and 3D are always arranged so as to be divided into four and can be imaged by one ITV camera 3 for each flow velocity measurement area 31.

  In each ITV camera 3, each flow velocity measurement area 31 is divided into four, and measurement areas 33 for four measurement lines are set in advance. That is, in the image of the first ITV camera 3A, the flow velocity of the flow velocity side lines q1, q2, q3, and q4 at the center position of each measurement area 33 for the four measurement lines is measured, and in the image of the second ITV camera 3B, the four measurement line segments are measured. The flow velocity side lines q5, q6, q7, and q8 at the center of each measurement area 33 are measured. Similarly, the third ITV camera 3C includes the flow velocity side lines q9 to q12, and the fourth ITV camera 3D includes the flow velocity side lines. The flow rates of q13 to q16 are measured, and the flow rates for a total of 16 survey lines are measured.

  In addition, the river cross-sectional area to the water surface of each measurement area 33 of the first to fourth flow velocity measurement areas 31A, 31B, 31C, and 31D corresponds to the flow velocity side lines q1 to q16 in order from the left in FIG. , S2, S3,... S15, S16. Therefore, the river cross-sectional area S is a total value of S1 to S16.

  If the average flow velocity for the 16 survey lines is v1, v2, v3,... V15, v16 in order from the left in FIG. 2 corresponding to the flow velocity side lines q1 to q16, the total flow rate Q of the river is The total value of the flow rates Q1 to Q16 in each measurement area 33 corresponding to the flow velocity side lines q1 to q16. That is, Q = Q1 + Q2 + ... + Q15 + Q16 = (S1 * v1) + (S2 * v2) + ... + (S15 * v15) + (S16 * v16).

  Accordingly, the total flow rate Q is automatically calculated by the OF processing device 21 by measuring the flow velocities v1 to v16 for 16 survey lines.

  Referring also to FIG. 3, each of the first to fourth ITV cameras 3A to 3D is provided with two near-infrared projectors 35 for illuminating the river surface. The 4 ITV cameras 3A to 3D may be a revolving type whose position is adjustable or a fixed type which is set at a fixed position.

  The first to fourth ITV cameras 3A to 3D and the near-infrared projector 35 are connected to the optical termination 9 of the observation station 7 as shown in FIG. It is transmitted to the terminal portion 37 of the optical termination 15 of the observation station 13 via the fiber cable 11.

  A video input unit 39 and a camera control unit 41 in the ITV control device 19 are connected to the terminal unit 37. The camera control unit 41 gives a command for controlling the imaging operation of the first to fourth ITV cameras 3A to 3D.

  In the video input unit 39, the first to fourth video input units 43 </ b> A to 43 </ b> D corresponding to the first to fourth ITV cameras 3 </ b> A to 3 </ b> D are connected to the terminal unit 37. The four video input units 43 </ b> A to 43 </ b> D are connected to the video distributor 45. From the video distributor 45, the image signals of the first to fourth ITV cameras 3A to 3D are transmitted to the four OF processing devices 21, and the image signals pass through the screen quadrant 47. It is transmitted to a monitor device 49 such as a CRT. In this monitor device 49, since the screen is divided into four and four images of the first to fourth ITV cameras 3A to 3D are simultaneously displayed, monitoring and checking can be easily performed.

  Further, for example, first to fourth recording devices 51A to 51D as recording means corresponding to the first to fourth ITV cameras 3A to 3D are connected to the video distributor 45, and each of them corresponds. An image can be recorded on a video tape or the like. The first to fourth recording devices 51A to 51D are configured to be controlled by, for example, a recording control device 53 as a recording control unit. For example, the recording control device 53 gives a command to start recording when the water level data by the water level gauge 23 described above exceeds a preset water level reference value and a command to stop recording when the water level data becomes lower than the water level reference value. This is given to the first to fourth recording devices 51A to 51D.

  Each of the OF processing devices 21 is connected to a CPU 55 as a central processing unit of the control device 17, and the CPU 55 includes a display 57 such as a CRT as a display device for displaying programs, data, and the like, and various kinds of devices. For example, a keyboard 59 and a mouse 61 are connected as input devices for inputting the data and program.

  Further, in addition to the four OF processing devices 21 described above, another OF processing device 21 for calculating the flow rate analyzes each of the image signals by the density gradient method and sets each measurement area 33 in advance. The river cross-sectional area S in the river width direction is calculated from the first to fourth river flow velocity calculation units 63A to 63D that calculate the flow velocities v1 to v16 of 16 survey lines q1 to q16 and the water level data transmitted from the water level gauge 23. The river cross-sectional area calculating unit 65, the river cross-sectional area S by the river cross-sectional area calculating unit 65, and the flow velocity values v1 to v16 for each of the survey lines q1 to q16 by the first to fourth river flow velocity calculating units 63A to 63D are integrated. And a river flow rate calculation unit 67 for calculating the total flow rate Q.

  The water level gauge 23 is shown in FIG. 3 with the intermediate process omitted, but as shown in FIG. 1 described above, the water level converter 25, the optical transmission device 27, and the optical termination of the observation station 7 are shown. 9 is connected to the optical termination 15 of the observation station 13 via the optical fiber cable 11. Therefore, the water level data is input from the optical termination 15 and the optical transmission device 29 to the OF processing device 21 and the recording control device 53 via the data logger 69 that stores the water level data.

  Further, a wind direction anemometer transmitter 71 is provided in the vicinity of the river to be measured, and the wind direction anemometer data is transmitted to the wind direction anemometer converter 73 of the control device 17, and the modem 75 is transmitted from the wind direction anemometer converter 73. To the OF processing device 21. The OF processing apparatus 21 corrects the influence of the wind direction and wind speed on the river flow velocity.

  Next, the speed extraction principle in the 1st-4th river flow velocity calculating part 63A-63D of the OF processing apparatus 21 is demonstrated.

  Referring to FIGS. 4A, 4B, and 4C, in this embodiment, speed extraction is performed by an optical flow method, and this optical flow method is a method for each point (pixel) from a moving image. It is a method to find out where and how fast each point has moved, by examining the spatial and temporal changes in shading.

  For example, as shown in FIG. 4A, the pixels on the captured image are converted into 256 levels of shade, a certain shade pattern (gradient) is recognized, and the shade pattern on the screen 77 at time t. However, as shown in FIG. 4B, the flow velocity is measured by determining where in the next continuous image at the time (t + Δt) after the lapse of the time Δt has moved. . The flow rate is measured by analyzing the concentration gradient method.

  In the optical flow method of this embodiment, the flow rate is obtained by performing the above-described series of processing in 2 seconds within the measurement range. Here, for easy understanding of the extraction principle, the movement of the pixel a on the screen 77 is considered only in a single X direction (the X-X ′ line direction in the figure). The flow rate calculation procedure is as follows.

(1) Perform image input. For example, continuous images at 1/30 second intervals are input.

(2) Perform calculation by optical flow. That is, two continuous screens 77 are extracted from the image input in the above procedure (1), and the movement amount of the pixel a having a certain luminance gradient (brightness pattern) is calculated. For example, when the two screens 77 of the image at time t in FIG. 4A and the image at time (t + Δt) in FIG. 4B are extracted, the movement of the pixel a is the image of the two screens 77. As shown in the upper difference, if the movement of the pixel a is only in a single X direction, the difference in the X direction on the image and the movement amount of the pixel a are the same. However, when it is shifted from the X direction, it is different from the difference on the image.

  Therefore, in order to obtain the movement amount of the pixel a, the velocity vector of the pixel a is obtained as shown in FIG. Is displayed. Based on this velocity vector, the amount of movement of the pixel a is calculated.

(3) Perform speed correction. The moving amount of the pixel a is corrected to a speed based on information on a preset shooting distance and converted into a speed.

(4) Further, the effectiveness of the magnitude and direction of the velocity is determined, and the influence of disturbances such as vortex, retrograde, and meandering flow is removed, and the average flow velocity within the measurement range is calculated.

  Therefore, based on the above velocity extraction principle, the first to fourth river flow velocity calculation units 63A to 63D have average flow velocity v1 to v16 corresponding to 16 survey lines q1 to q16 over the entire length in the width direction of the river shown in FIG. Is automatically calculated.

  The river flow rate calculation unit 67 calculates the total river flow rate Q = Q1 + Q2 +... + Q16 = (S1 × v1) + from the average flow velocities v1 to v16 and the river cross-sectional areas S1 to S16 of the corresponding measurement areas 33. (S2 × v2) +... + (S16 × v16) is automatically calculated.

  As described above, the river flow rate measurement system 1 and the river flow velocity measurement system according to this embodiment are non-contact measurement methods for analyzing images captured by a plurality of ITV cameras 3, and automatically adjust the water level, flow velocity, and flow rate. And it can be monitored in real time. In the measurement, a float (tracer) is not required. In addition, there is no need to insert and install equipment in the water, and observation is possible even when there is a high flow rate or a large amount of falling objects.

  Furthermore, it is possible to analyze a complicated flow velocity distribution, and to perform post-analysis / verification using a video tape of the recording device 51.

  In addition, because of unmanned observation, the danger of observation work during floods or in bad weather can be eliminated, safety and labor saving can be achieved, and the cost of observation work can be reduced.

  Furthermore, it is possible to grasp the surface flow velocity distribution from the video. For example, it is possible to measure up to about 50 m in the width direction of the river with one ITV camera 3. By the way, other non-contact methods for measuring flow velocity include the Doppler method that uses the reflection of radio waves and ultrasonic waves. In this method, measurement is performed in a narrow irradiation area of radio waves and ultrasonic waves, and wide crossing of rivers is performed. The measurement value at the upper point is used as a representative value. However, in the case of this optical flow method, since the flow velocity distribution is captured by the image and a wide range of measurement is performed with one ITV camera 3, a plurality of ITV cameras 3 are integrated to cover the entire length of the river in the width direction. Enables more accurate observation.

  In addition, measurement is possible even when the water flow is not regular, such as a curved portion of a river.

  In addition, because of the video signal measurement method, it is possible to remotely observe the image from the ITV camera 3 transmitted to the office via the optical fiber cable 11 laid for river management, and effective use of the optical fiber communication network. One can expect.

  In addition, this invention is not limited to embodiment mentioned above, It can implement in another aspect by making an appropriate change.

It is a schematic explanatory drawing of the river flow measurement system of an embodiment of this invention. It is a rough river bed sectional view showing the installation state of the ITV camera in the width direction of the river to be measured. It is a block diagram of the configuration of the control device used in the river flow rate measurement system of the embodiment of the present invention. (A)-(C) is explanatory drawing of the speed extraction principle by OF processing apparatus.

Explanation of symbols

1 River flow measurement system 3, 3A-3D ITV camera (remote monitoring imaging means)
11 Optical fiber cable 17 Control device 21 OF processing device (optical flow processing device)
23 Water level gauge (water level measuring means)
31, 31A to 31D Flow velocity measurement area 33 Measurement area 47 Screen quadrant 51A to 51D First to fourth recording devices (recording means)
53 Recording controller (recording controller)
55 CPU
63A to 63D First to fourth river flow velocity calculation unit 65 River cross-sectional area calculation unit 67 River flow rate calculation unit 71 Wind direction anemometer transmitter

Claims (6)

  A plurality of remote monitoring imaging means divides and captures the entire water surface in the width direction of the river and transmits the image signal from the imaging means to the control device, and the control device analyzes the image signal by the density gradient method. A river flow velocity measuring method, comprising: calculating flow velocity in a measurement area for a plurality of survey lines in a predetermined width direction of the river.   A plurality of remote monitoring imaging means divides and captures the water surface of the entire length in the width direction of the river, measures the water level of the river to be imaged by the water level measuring means, and uses the image signal from the imaging means and the water level measuring means. The water level data is transmitted to the control device, and the control device calculates the flow velocity of the measurement area for a plurality of survey lines in the river width direction set in advance by analyzing the image signal by the concentration gradient method, and the water level data A river flow rate measuring method comprising: calculating a river cross-sectional area in the width direction of the river and calculating a total flow rate from the river cross-sectional area and a flow velocity value for each of the survey lines.   The image recording from the remote monitoring imaging means is started when the water level data exceeds a preset water level reference value, and the image recording is stopped when the water level data becomes lower than the water level reference value. The river flow rate measuring method according to claim 2. A plurality of remote monitoring imaging means are arranged in the river to divide the water surface of the entire length in the width direction of the river into a plurality of images,
A control device comprising a river flow velocity calculation unit for analyzing the image signal transmitted from the remote monitoring imaging means by a concentration gradient method and calculating flow velocity in a measurement area for a plurality of measurement lines in a predetermined river width direction. A river flow velocity measurement system characterized by being provided. A plurality of remote monitoring imaging means are arranged in the river to divide the water surface of the entire length in the width direction of the river into a plurality of images,
Providing a water level measuring means for measuring the water level of the river to be imaged;
A river flow velocity calculation unit for analyzing the image signal transmitted from the remote monitoring imaging means by a concentration gradient method and calculating a flow velocity in a measurement area for a plurality of measurement lines in a predetermined river width direction;
A river cross-sectional area calculation unit for calculating a river cross-sectional area in the width direction of the river from the water level data transmitted from the water level measurement means, a river cross-sectional area by the river cross-sectional area calculation unit, and a line for each measurement line by the river flow velocity calculation unit A river flow rate measuring system comprising a control device including a river flow rate calculation unit that calculates a total flow rate from the flow velocity value of the river. The control device includes recording means for recording the image signal, and commands to start recording when the water level data exceeds a preset water level reference value and stop recording when the water level data becomes lower than the water level reference value. 6. The river flow rate measuring system according to claim 5, further comprising a recording control unit for giving a command to the recording means.