阅读说明：本技术 一种基于图片处理的挑射流冲坑地形演变实时监测方法 (image processing-based real-time monitoring method for pit-rushing terrain evolution of jet flow ) 是由 姚莉 陈辉 石莎 陈柏全 吴建华 于 2019-09-09 设计创作，主要内容包括：本发明公开了一种本发明的基于图片处理的挑射流冲坑地形演变实时监测方法,包括以下步骤：(1)制作长方形框架,焊接网格；(2)在钢丝网网线交点系纺织线；(3)对系有纺织线的交点进行编号；(4)将长方形框架水平放置于将形成冲坑位置正上方足够高度处；(5)在合适的角度拍摄照片,使照片中能够显示完整的地形、框架、钢丝线、纺织线；(6)将图片置于CAD中,延长任意一条纺织线,使其与地形线相交,求得延长线的长度即可求得该点地形高程；(7)将不同时刻的照片进行上述处理,可以得出不同时刻三维冲坑底坡地形图。本发明的一种基于图片处理的挑射流冲坑地形演变实时监测方法,能实时(动态)演变过程,经济方便,精度较高。(the invention discloses a method for monitoring the topographic evolution of a shot flow pit in real time based on picture processing, which comprises the following steps: (1) manufacturing a rectangular frame, and welding grids; (2) weaving threads are tied at the intersection points of the steel wire mesh wires; (3) numbering the intersections tied with the textile threads; (4) horizontally placing the rectangular frame at a sufficient height right above the position where the pit punching is to be formed; (5) the method comprises the following steps of taking a picture at a proper angle, so that the complete terrain, a frame, steel wires and textile wires can be displayed in the picture; (6) placing the picture in CAD, extending any one textile line to make it intersect with the terrain line, and obtaining the length of the extension line to obtain the terrain elevation of the point; (7) the photos at different times are processed to obtain three-dimensional pit-punching bottom slope maps at different times. The method for monitoring the topographic evolution of the jet stream pit-punching based on picture processing can be used for monitoring the evolution process in real time (dynamically), and is economical, convenient and high in precision.)

1. A method for monitoring the topographic evolution of a shot stream pit in real time based on picture processing is characterized by comprising the following steps: the method comprises the following steps:

(1) Manufacturing a rectangular frame, wherein the area of the frame can cover the whole pit punching range, welding a steel wire mesh on the frame, and enabling the mesh wires of the steel wire mesh to be parallel to the length and the width of the rectangular frame respectively, wherein the size of each steel wire mesh is 2cm multiplied by 2 cm;

(2) Weaving threads are tied at the intersection points of the mesh threads of the steel wire mesh at intervals of 4cm, each row of weaving threads are coated with the same color and have the same length, the colors and the lengths of the weaving threads in different rows are different, and the other ends of the weaving threads are tied with sinking blocks;

(3) Numbering the intersection points of the tied textile threads, wherein the transverse direction is represented by x, and the longitudinal direction is represented by y, so that the position of any textile thread on a horizontal plane is (x _i, y _j), and i and j are the number of the textile points in the transverse direction and the longitudinal direction;

(4) horizontally placing the rectangular frame at a position which is just above the position where the pit is to be formed and has enough height, so that the rectangular frame does not influence the nappe of the jet flow;

(5) The method comprises the following steps of taking a picture at a proper angle, so that the complete terrain, a frame, steel wires and textile wires can be displayed in the picture;

(6) placing the picture in CAD, extending any one textile line to make it intersect with the terrain line, and obtaining the length of the extension line to obtain the terrain elevation of the point;

(7) The photos at different times are processed to obtain three-dimensional pit-punching bottom slope maps at different times.

2. the method for real-time monitoring evolution of pit-flushing terrain by selective streaming based on picture processing as claimed in claim 1, wherein the solving process of the step (6) is subdivided into the following steps of (i) solving the height of a pit-flushing bottom slope corresponding to a spinning line with the serial number of (x _i, y _j), (x _i, y _j) and (x _i-1, y _j), respectively, setting the intersection points of (x _i, y _j) and (x _i-1, y _j) as c and a, respectively, (x _i-1, y _j) the other end of the spinning line as b, extending the spinning line with the serial number of (x _i, y _j) to intersect the terrain at a point d, extending two practically parallel lines of a rectangular frame in the picture to a point j and a point k, respectively connecting j and k, connecting a point a and c and extending a line to a point l, extending a line to a line j and a line to a point l, extending line to an m, extending line to a line ab and a line to a point cd, respectively calculating three-dimensional calculation of the lines in CAD, im, cm, and cd, respectively, and calculating the ratio of the intersection points of the corresponding two-dimensional projection of the corresponding parallel lines to the corresponding camera head in the real space, and calculating the ratio of the corresponding point 1:

If IM and ID are infinite, IM/ID is 1, CM length is (x _i-1, y _j) correspondent textile line length, so that it can calculate CD, according to the above-mentioned method, can successively solve the height difference of punching pit base slope and rectangular frame correspondent to any textile line under the above-mentioned textile line, and uses ground surface as 0-0 surface to measure the rectangular frame height, and respectively subtract the above-mentioned height difference so as to obtain the height z _k of correspondent point.

3. The method for real-time monitoring of the topographic evolution of the exploding jet stream pit based on the picture processing as claimed in claim 1, wherein the method of step (7) is characterized in that the coordinates of the plane of the intersection point with any number (x _i, y _j) are (2 xi, 2 xj) (unit: cm), the coordinates of the slope just below the intersection point with any number (x _i, y _j) are (2 xi, 2 xj, z _k), a series of coordinates of the pit-exploding slope are imported into CAD, a complete three-dimensional map of the pit-exploding slope can be obtained by linear interpolation, and the three-dimensional map of the pit-exploding slope can be obtained by processing the pictures at different times.

Technical Field

The invention relates to a method for monitoring the topographic evolution of a jet stream pit on the basis of image processing in real time, and belongs to the field of hydraulic and hydroelectric engineering.

background

The gathering jet flow water tongues are connected with the water flow at the downstream river channel or the dam foundation to form a scouring pit. As is well known, for the jet flow, energy dissipation is divided into three parts of energy dissipation from the front section of an energy dissipater, energy dissipation in the air and energy dissipation of downstream spin-rolling scouring, and about 50% -80% of energy is dissipated in a scouring pit. The large and unstable dynamic water pressure pulsation, aeration, turbulence, submerging and whirling and other complex hydraulic conditions are mixed and mixed, and the multi-scale riverbed space geological conditions cause different threats and hazards to riverway scouring and structural stability in the forming process of the scour pits.

the flushing characteristic of the deflecting stream downstream flushing pit involves three phases of solid (rock) -liquid (water) -gas (air). Some characteristic parameters related to the shape of the erosion pit are currently the main research issue, wherein the important characteristic of the maximum erosion pit depth is of great concern. The measurement of important characteristic parameters such as the maximum pit punching depth and the like of the specific pit punching shape is very complicated. The existing technology of hydraulic model test measures the drift current downstream flushing pit, generally, after the flushing pit is continuously flushed for several hours, the terrain is measured after the flushing pit reaches balance, the evolution process of the flushing pit is monitored in real time, measuring instruments are conventional tape measures, and the accuracy of important indexes such as the measured flushing pit shape, the maximum flushing pit depth and the maximum sedimentation height cannot be guaranteed.

Disclosure of Invention

the purpose of the invention is as follows: in order to overcome the defects in the prior art, the invention provides a method for monitoring the topographic evolution of the shot-stream pit-rushing based on picture processing in real time, which can realize the real-time (dynamic) evolution process, and is economic and convenient and high in precision.

The technical scheme is as follows: in order to solve the technical problem, the invention discloses a method for monitoring the topographic evolution of a shot stream pit in real time based on image processing, which comprises the following steps:

(1) manufacturing a rectangular frame, wherein the area of the frame can cover the whole pit punching range, welding a steel wire mesh on the frame, and enabling the mesh wires of the steel wire mesh to be parallel to the length and the width of the rectangular frame respectively, wherein the size of each steel wire mesh is 2cm multiplied by 2 cm;

(2) weaving threads are tied at the intersection points of the mesh threads of the steel wire mesh at intervals of 4cm, each row of weaving threads are coated with the same color and have the same length, the colors and the lengths of the weaving threads in different rows are different, and the other ends of the weaving threads are tied with sinking blocks;

(3) Numbering the intersection points of the tied textile threads, wherein the transverse direction is represented by x, and the longitudinal direction is represented by y, so that the position of any textile thread on a horizontal plane is (x _i, y _j), and i and j are the number of the textile points in the transverse direction and the longitudinal direction;

(4) horizontally placing the rectangular frame at a position which is just above the position where the pit is to be formed and has enough height, so that the rectangular frame does not influence the nappe of the jet flow;

(5) The method comprises the following steps of taking a picture at a proper angle, so that the complete terrain, a frame, steel wires and textile wires can be displayed in the picture;

(6) placing the picture in CAD, extending any one textile line to make it intersect with the terrain line, and obtaining the length of the extension line to obtain the terrain elevation of the point;

(7) The photos at different times are processed to obtain three-dimensional pit-punching bottom slope maps at different times.

preferably, the solving process of the step (6) is subdivided into the following steps of solving the height of the pit-punching bottom slope corresponding to the textile line with the serial number of (x _i, y _j), respectively setting the intersection points of (x _i, y _j) and (x _i-1, y _j) as c and a, (x _i-1, y _j) as b, extending the textile line with the serial number of (x _i, y _j) to intersect the terrain at a point d, extending two lines which are actually parallel to the rectangular frame in the picture to intersect at a point j and a point k, connecting the point a and the point c to a point l, connecting the parallel line l and b to a point m, extending the parallel line to a point cd, and intersecting the point i, respectively calculating the intersection lines im, id, cm and cd in CAD, respectively representing the corresponding intersection points with large letters in three dimensions (assuming that the intersection points correspond to each other position in space are projected according to a two-dimensional variable camera shooting rule, and obtaining an image with a variable camera shooting ratio of 1:

Fifthly, according to the method, the height difference between a pit-punching bottom slope corresponding to any one of the textile lines and a rectangular frame can be solved in sequence, the height of the rectangular frame is measured by taking the ground as 0-0 surface, and the height difference is subtracted respectively, so that the height z _k of a corresponding point can be obtained;

Preferably, the step (7) is that the coordinates of the plane of the intersection point with any number (x _i, y _j) are (2 xi, 2 xj) (unit: cm), the coordinates of the bottom slope under the intersection point with any number (x _i, y _j) can be obtained, (2 xi, 2 xj, z _k), a series of pit-punching bottom slope coordinates are led into CAD, and linear interpolation can be carried out to obtain a complete three-dimensional pit-punching bottom slope map, the photos at different times are processed as above, the three-dimensional pit-punching bottom slope map at different times can be obtained.

has the advantages that: the method for monitoring the evolution of the selective jet flow pit-flushing terrain in real time based on picture processing can realize non-contact measurement and calculation of the selective jet flow pit-flushing terrain, and avoid disturbance of contact type terrain measurement on water flow motion to influence test effect and measurement precision; meanwhile, the dynamic evolution of the selective jet flow pit-flushing terrain is realized by batch processing of the pictures at different moments, and the method has great significance for researching the selective jet flow pit-flushing formation mechanism.

Drawings

FIG. 1 is a three-dimensional view of a rectangular standard frame.

fig. 2 is a front view of a rectangular standard frame.

Fig. 3 is a right side view of a rectangular standard frame.

Fig. 4 is a real straight line from the intersection point of (xi, yj) to the bottom slope and a bottom slope adjacent spinning line graph.

FIG. 5 is a schematic view of the straight line from the intersection point to the bottom slope in the photograph and the adjacent yarns on the bottom slope.

In the figure: 1 is a textile thread and 3 is an XOY plane.

Detailed Description

the present invention will be further described with reference to the accompanying drawings.

as shown in fig. 1 to 5, a method for real-time (dynamic) monitoring of formation evolution of a shot stream pit based on picture processing includes the following steps:

1, manufacturing a rectangular frame, wherein the area of the frame can cover the whole pit punching range, and welding a steel wire mesh on the frame, so that the mesh wires of the steel wire mesh are respectively parallel to the length and the width of the rectangular frame, and the size of each steel wire mesh is 2cm multiplied by 2 cm;

2 weaving threads are tied at the intersection points of the net threads of the steel wire net (stressed and straightened) at intervals of 4cm, each row of weaving threads are coated with the same color and have the same length, the colors and the lengths of the weaving threads of different rows are different, and small nuts are tied at the other ends of the weaving threads (figures 1, 2 and 3);

3, numbering the intersection points where the textile threads are tied, wherein the position on the horizontal plane where any textile thread is located is (x _i, y _j) when the transverse direction is represented by x and the longitudinal direction is represented by y;

4, horizontally placing the rectangular frame at a position which is just high enough above the position where the pit is formed, so that the rectangular frame does not influence the nappe of the jet flow;

5, taking a picture at a proper angle, so that the complete terrain, the frame, the steel wire and the textile wire can be displayed in the picture;

6, placing the picture in CAD, extending any one textile line to intersect with the terrain line, and obtaining the length of the extension line to obtain the terrain elevation of the point, wherein the solving process is subdivided as follows:

Solving the height of a pit-punching bottom slope corresponding to a textile line with the serial number of (x _i, y _j), setting the corresponding intersection points of (x _i, y _j) and (x _i-1, y _j) as c and a respectively, and setting the other end of (x _i-1, y _j) textile line as b, in a photo, extending the textile line with the serial number of (x _i, y _j) to intersect with the terrain at a point d, extending two lines which are actually parallel to a rectangular frame in the picture to intersect at a point j and a point k respectively, connecting the point j and the point k, connecting the point a and the point c to a point l, connecting the point l and the point b to a point m, extending an extension line ab and a line cd to a point i (such as the intersection point of 1- (x _i, y _j) to a pit-punching bottom slope connecting line right below, connecting the textile line of 2- (x _i-1, y _j) and a cuboid frame of 3-standard);

Measuring and calculating im, id, cm and cd in CAD;

in reality, capital letters represent points corresponding to corresponding positions (assuming that intersection points of parallel lines are at infinity);

Fourthly, according to the imaging rule of the camera: the three-dimensional space is projected, and the linear cross ratio is unchanged on a two-dimensional image. Equation 1 can be obtained:

If IM and ID are infinite, IM/ID is 1, CM length is the length of the corresponding textile thread (x _i-1, y _j), therefore, CD can be calculated;

fifthly, according to the method, the height difference between the pit bottom slope and the rectangular frame corresponding to the position under any textile line can be solved in sequence;

Measuring the elevation of the rectangular frame by taking the ground as 0-0 surface, and subtracting the height difference to obtain the elevation z _k of the corresponding point;

7 the coordinates of the plane of the intersection point with the arbitrary number (x _i, y _j) are (2 xi, 2 xj) (unit: cm), so that the coordinates of the bottom slope right below the intersection point with the arbitrary number (x _i, y _j) can be obtained (x _i, y _j, z _k);

8, importing a series of pit-punching bottom slope coordinates into CAD, and performing linear interpolation to obtain a complete three-dimensional pit-punching bottom slope map;

and 9, performing the processing on the photos at different times to obtain three-dimensional pit-punching bottom slope maps at different times.

the horizontal distance between adjacent textile lines in the same row (line) can be set according to actual conditions, and the horizontal distance between adjacent textile lines in the same row (line) is smaller for pit-punching terrains with high precision requirements.

The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.