Video monitoring apparatus and method for operating state of wave maker

Abstract

The present invention belongs to the technical field of movement monitoring, and provides a video monitoring apparatus and method for an operating state of a wave maker. When the operating state of the wave maker is monitored, an image collected by a camera is subjected to mark point detection and a central position is computed. Then, the position of each mark point is tracked in a dynamic video; and the operating condition of each wave paddle is assessed according to the motion state of the mark point. In the present invention, operating monitoring of the wave paddle is independent of a wave making control system, and the operating condition of the wave paddle is monitored in real time through a non-contact image measurement mode. The wave paddle is identified through LED; the positions of the mark points in each frame image are acquired through image perspective correction and binarization analysis; and the operating state of the wave paddle is judged according to the contrast among the mark points at different times and different spatial positions, thereby effectively reducing an error rate of the wave making control system for the operating monitoring of the wave paddle and greatly increasing experimental efficiency of simulating wave making.

Claims

1. A video monitoring apparatus for an operating state of a wave maker, the video monitoring apparatus comprising a computer, a camera with a fixed focus lens, a tripod with a pan-tilt, some red round LEDs and a driving control circuit board, wherein the camera is fixed to the tripod with pan-tilt and arranged on an outer side of an experimental pool; the camera has an optical axis and forms a certain angle with a movement direction of wave paddles and is connected with the computer through a transmission cable; a red round LED is arranged on each wave paddle in a visual region, and each LED is connected to the driving control circuit board; the driving control circuit board of the LED is connected with the computer through a RS232 interface; each wave paddle is seen as a mark point; when the operating state of the wave maker is monitored, an image collected by the camera is subjected to mark point detection and a central position is computed by image moments; then, the central position of every mark point are being tracked in a dynamic video by nearest neighbor tracking; and the operating state of each wave paddle is assessed according to a motion state of the corresponding mark point.

2. A video monitoring method for an operating state of a wave maker, comprising the following steps: step A: fixing a position of a camera after installing red round LEDs on wave paddles so that movement of the wave paddles and an optical axis of the camera form a certain angle; and adjusting an object distance and an aperture of a camera lens so that images achieved by the camera are all very clear; step B: performing system calibration during first operation; controlling a driving control circuit board by a PC to illuminate all the red round LEDs and simultaneously control the wave paddles to return to an initial position; achieving an image frame of wave paddles by the camera; extracting coordinates P.sub.a of all luminous mark points in an initialization state of the wave paddles through an image binarization method; numbering the mark points in an order from near to far; next, controlling the wave paddles to move to a maximum stroke by the PC; grabbing the wave paddle image and extracting coordinates defined as P.sub.b of all the mark points; meanwhile, enabling the positions of identified mark points to correspond to indexes of the mark points; forming a line segment P.sub.aP.sub.b.sup.i, i=1, 2, 3 . . . N by two coordinate positions recorded under each number, where N is the quantity of the mark points; because the movement of each wave paddle is limited to the line segment, P.sub.aP.sub.b.sup.i is called as a stroke line segment; additionally, forming a straight line l.sub.a by a point set P.sub.a of start positions and forming a straight line l.sub.b by a point set P.sub.b of end positions; setting a region between l.sub.a and l.sub.b as an analysis region W.sub.ROI; next, correcting the coordinates of the mark points in the image using perspective transformation P=M.sub.33P so that two straight lines formed by P are parallel l.sub.a//l.sub.b, i.e., new motion line segments are equal to each other |P.sub.aP.sub.b.sup.1|=|P.sub.aP.sub.b.sup.2|= . . . |P.sub.aP.sub.b.sup.N|; meanwhile, recording a perspective transformation matrix M.sub.33; P being a set of the coordinates of the mark points on l.sub.a and l.sub.b; P being a coordinate set of corrected points and M.sub.33 being the perspective transformation matrix; setting a two-dimensional coordinate plane with x axis coinciding with l.sub.a and y axis coinciding with P.sub.aP.sub.b.sup.i; and controlling the LED driving circuit board to close all the mark LED by the PC to enter an analysis waiting state after completing the above operation; step C: illuminating all the red round LEDs while starting a wave making procedure; and setting the camera to enter a uniformly-spaced consecutive collection mode; step D: performing binarization analysis on a current image captured by the camera; extracting the positions of the mark points in the region W.sub.ROI; and modifying the positions of the mark points using the perspective transformation matrix M.sub.33; step E: contrasting the position of the current mark point with the previous position; recording the index of the mark point for the first time if the position is not changed; contrasting the position of each mark point at the current time with the position of an adjacent mark point along an axial direction; computing a position difference between the positions; and recording the mark point of the number for the second time if the difference between adjacent positions is greater than a set threshold T; step F: considering the wave paddle with the same index in step E to have a failure if a certain mark point is recorded continuously twice; and also considering the adjacent wave paddles and only recorded for the first time to have a failure; step G: displaying an alarm by the computer when the failure occurs; meanwhile closing the wave making procedure; then controlling the driving control circuit board to close all the mark lamps except the wave paddles with failure; and if no failure occurs, repeating steps D-E until a wave making experiment is completed, and closing all the mark lamps and stopping the monitoring procedure.

Description

DESCRIPTION OF DRAWINGS

(1) The sole FIGURE is a structural schematic diagram of a video monitoring apparatus of the present invention.

(2) In the FIGURE: 1 computer; 2 camera; 3 LED driving circuit board; 4 tripod; 5 LED; 6 experimental pool; and 7 wave paddle.

DETAILED DESCRIPTION

(3) Specific embodiments of the present invention are further described below in combination with accompanying drawings and the technical solution.

(4) A video monitoring method for an operating state of a wave maker, as shown in the sole FIGURE for the structure, comprises a computer 1; a camera 2 with a fixed focus lens; a tripod 4 with a pan-tilt; a plurality of LED circular lamp beads 5 and a driving control circuit board 3. The camera 2 is fixed to the tripod 4 and arranged on the outer side of an experimental pool 6; an optical axis forms a certain angle with the movement direction of wave paddles 7 and is connected with the computer 1 through a transmission conducting wire. A red round LED 5 is arranged on each wave paddle 7 in a visual region, and each LED is connected to the driving control circuit board 3. The driving control circuit board 3 of the LED is connected with the computer 1 through a RS232 interface. When the operating state of the wave maker is monitored, an image collected by the camera 2 is subjected to mark point detection and a central position is computed. Then, the position of each mark point is tracked in a dynamic video; and the operating condition of each wave paddle 7 is assessed according to the motion state of the mark point. The specific method is described as follows:

(5) step A: fixing the shooting position of the camera 2 after installing the LEDs 5 on the wave paddles 7 so that the movement of the wave paddles 7 and the optical axis of the camera 2 form a certain angle; meanwhile, adjusting an object distance and an aperture of a camera lens so that the images achieved are all very clear;

(6) step B: performing system calibration during first operation; controlling the LED driving control circuit board 3 by the computer 1 to illuminate all the LED mark lamps 5 and simultaneously control the wave paddles 7 to return to the initial position; achieving an image frame on the site by the camera 2; extracting coordinates P.sub.a of all luminous mark points 5 in the initialization state of the wave paddles 7 through an image binarization method; numbering the mark points 5 in an order from near to far; next, controlling the wave paddles 7 to move to a maximum stroke by the PC 1; grabbing the site image and extracting the coordinates P.sub.b of all the mark points 5; meanwhile, enabling the positions of the identified mark points to correspond to the numbers of the mark points; forming a line segment P.sub.aP.sub.b.sup.i=1, 2, 3 . . . N by two coordinate positions recorded under each number, wherein N is the quantity of the mark points; because the movement of each wave paddle is limited to the line segment, P.sub.aP.sub.b.sup.i is called as a stroke line segment; additionally, forming a straight line l.sub.a by a point set P.sub.a of the start positions and forming a straight line l.sub.b by a point set P.sub.b of the end positions; setting a region W.sub.ROI between l.sub.a and l.sub.b as an analysis region; next, correcting the coordinates of the mark points in the image using perspective transformation P=M.sub.33P (P being a set of the coordinates of the mark points on l.sub.a and l.sub.b, P being a coordinate set of corrected points and M.sub.33 being the perspective transformation matrix;) so that two straight lines formed by P are parallel l.sub.a//l.sub.b, i.e., new motion line segments are equal to each other |P.sub.aP.sub.b.sup.1=|P.sub.aP.sub.b.sup.2|= . . . =|P.sub.aP.sub.b.sup.N|; meanwhile, recording a perspective transformation matrix M.sub.33; setting a two-dimensional coordinate plane with x axis coinciding with l.sub.a and y axis coinciding with P.sub.aP.sub.b.sup.i; and controlling the LED driving circuit board 3 to close all the mark lamps by the PC 1 to enter an analysis waiting state after completing the above operation;

(7) step C: illuminating all the red round LEDs 5 while starting a wave making procedure; and setting the camera 2 to enter a uniformly-spaced consecutive collection mode;

(8) step D: performing binarization analysis on the current image; extracting the positions of the mark points 5 in the region W.sub.ROI; and modifying the positions of the mark points using the perspective transformation matrix M.sub.33;

(9) step E: contrasting the position of the current mark point with the previous position; at this moment, recording the mark point of the number for the first time if the position is not changed; contrasting the position of each mark point at the current time with the position of an adjacent mark point along an axial direction; computing a position difference between the positions; and at this moment, recording the mark point of the number for the second time if the difference between adjacent positions is greater than a set threshold T;

(10) step F: considering the wave paddle 7 of the number to have a failure if a certain mark point 5 is recorded continuously twice; and also considering the wave paddles 7 of the number successively adjacent thereto and only recorded for the first time to have a failure;

(11) step G: displaying an alarm by the computer when the failure occurs; meanwhile closing the wave making procedure; then controlling the LED driving control circuit board 3 to close all the mark lamps 5 except the wave paddles 7 with failure; and if no failure occurs, repeating steps D-E until a wave making experiment is completed, and closing all the mark lamps 5 and stopping the monitoring procedure.

(12) In conclusion, an LED mark point 5 is installed in the same position of each wave paddle 7 first before monitoring; then the camera 2 is arranged and system calibration is conducted; next, automatic monitoring of the procedure is started; during measurement, the mark points 5 are continuously detected and the positions of the mark points 5 are acquired; and finally, the operating state of the wave paddle 7 is judged according to relationships among the position of the current mark point, the position at the previous time and spatial adjacent positions.