CN107391631A - A kind of electric transmission line channel solid space monitoring and fast ranging method - Google Patents

Abstract

The invention provides a three-dimensional space monitoring and rapid distance measurement method for a transmission line channel, which includes calibrating the binocular vision system, obtaining the internal and external parameters of the binocular vision system, and using the calibrated internal and external parameters of the binocular vision system by matching the characteristic points of the transmission line Carry out three-dimensional reconstruction of the matched transmission line feature points, use the reconstructed three-dimensional coordinates of the feature points to establish the transmission line space equation, and then establish the transmission line three-dimensional monitoring area model through the transmission line space equation and the plane monitoring area, and calculate the monitoring area space points The minimum distance to the space equation of the transmission line, so as to establish a database of monitoring space point-minimum distance, and finally through the three-dimensional reconstruction of the foreign object feature points, the database can be directly used to determine whether the foreign object has invaded, and the distance between the foreign object and the transmission line can be obtained. By establishing a 3D spatial point database and a model of the corresponding spatial distance relationship in the early stage, this method can greatly reduce the amount of real-time operation of 3D reconstruction and space ranging in the later stage, and provide effective guarantee for real-time monitoring of transmission lines.

Description

A three-dimensional space monitoring and fast ranging method for transmission line channels

technical field

The invention relates to the technical field of smart grids, in particular to a three-dimensional space monitoring and fast ranging method for transmission line channels.

Background technique

Electric power is an important basic industry of the country, and the stability and security of power supply is the prerequisite for ensuring the stable and rapid development of a country. In the national grid, transmission lines are generally located in complex and remote environments, and it is very important to ensure the safety of transmission lines. For a long time, relevant departments have believed that the operation and maintenance of transmission line channels is mainly a management issue. They usually use methods such as manual squatting and crowd protection to manage the operation and maintenance. This method not only consumes a lot of manpower and material resources, but also has unsatisfactory results. At present, monitoring equipment such as video and radar are installed on towers, and hidden dangers that endanger transmission lines are detected by manually identifying the collected data. However, the accuracy and reliability of these methods cannot be guaranteed, which is not conducive to popularization and application. .

With the development of image processing, machine vision technology based on automatic machine recognition has been widely used. However, traditional machine vision systems based on video surveillance are prone to misjudgment due to the loss of depth information in the process of light information collection into video. .

Contents of the invention

The purpose of the present invention is to provide a three-dimensional space monitoring and rapid ranging method for transmission line channels, which monitors transmission line channels based on a binocular vision system, and obtains complete information of detection points in the three-dimensional monitoring area through three-dimensional reconstruction, which can realize detection of foreign objects Whether it is intruded or not, and the distance between the foreign object and the transmission line can be quickly judged, making the detection more accurate, and greatly improving the real-time detection speed and efficiency.

In order to achieve the above object, the present invention provides a method for three-dimensional space monitoring and rapid distance measurement of transmission line channels, including the following steps:

(1) Calibrate the binocular vision system to obtain the internal and external parameters of the binocular vision system;

(2) The characteristic points of the transmission line are obtained by matching the brightness values in the left and right imaging of the binocular vision system in the roughly selected area, and then use the calibrated internal and external parameters of the binocular vision system to perform three-dimensional reconstruction of the matched transmission line feature points, and use the pole tower cross arm The center is the origin, establish a three-dimensional space coordinate system, and obtain the three-dimensional coordinates of feature points;

(3) Using the reconstructed three-dimensional coordinates of the feature points to establish the space equation of the transmission line;

(4) Establish a three-dimensional coordinate point set through the transmission line space equation and the plane monitoring area, that is, the three-dimensional monitoring area model of the transmission line;

(5) Calculate the minimum distance value between all spatial points in the three-dimensional coordinate point set and the transmission line spatial equation;

(6) The set of three-dimensional coordinate points set up according to step (4) is the monitoring data, and the space point and the corresponding minimum distance value in the set of three-dimensional coordinate points are established according to the minimum distance value of the space point calculated in step (5) and the space equation of the transmission line Monitoring model database, that is, monitoring spatial point-minimum distance database;

(7) In daily monitoring, by detecting foreign matter feature points and reconstructing its three-dimensional coordinates, the reconstructed three-dimensional coordinates are compared with the monitoring space point-minimum distance database database constructed in step (6) to determine whether foreign matter enters the alarm area, and the database can quickly estimate the distance of the foreign object from the transmission line.

Further, the step (1) binocular vision system calibration step is: use Zhang's method to calibrate the internal parameters of the binocular vision system α, β, γ, μ, υ before the installation of the binocular vision system, Among them, α is the scaling factor on the x-axis, β is the scaling factor on the y-axis, γ is the oblique factor between the image coordinate and the optical axis coordinate, μ is the position of the optical center of the optical axis on the x-axis of the image coordinate, and υ is the light The position of the optical center of the axis on the y-axis of the image coordinates; after the binocular vision system is set up, use the self-calibration method to calibrate the external parameters R and t of the binocular vision system, where R is the rotation factor and t is the translation factor.

Further, the specific steps of selecting the feature points of the transmission line in the step (2) are as follows: firstly, the area with obvious geometric features is selected as the rough selection area of feature points, and then the brightness value in the rough selection area is selected through the left and right imaging of the binocular vision system Matching for precise feature point selection.

Further, the area with obvious geometric features is the connection area between the line and the tower and the lowest area of the sag of the transmission line.

Further, the step (3) utilizes the reconstructed three-dimensional coordinates of the feature points to establish the transmission line space equation as:

Where σ ₀ is the horizontal stress at each point of the wire, in N/mm ² ;

γ is the specific load of the wire, in N/m.mm ² ;

k is the horizontal distance from the wire suspension point to the origin, in m;

l _AO is the horizontal distance between the lowest point of the wire and the suspension point,

The unit is m;

l is the gear distance, the unit is m;

h is height difference, the unit is m.

Further, in the step (4), the three-dimensional monitoring area model is established. First, based on the transmission line space equation, determine the three-dimensional coordinates (x, y, z) of the intersection point of the transmission line space equation on a certain plane; set the intersection point three-dimensional The coordinate (x, y) is the center, and the distance a from the transmission line is the edge of the monitoring range, and the plane monitoring area is established, and the range of the monitoring area on the x and y axes is:

(x-a)<x<(x+a),

(y-a)<y<(y+a)

Finally, based on the range of x and y coordinates of the plane monitoring area and the range of z values of the depth of the transmission line space equation, a set of three-dimensional coordinate points is established, that is, a three-dimensional monitoring area model.

Further, the minimum distance value from the space point to the transmission line space equation in the step (5), through the reconstructed space point three-dimensional coordinates (x _k , y _k , z _k ), taking z _k as the depth information of the same monitoring plane Bring in the space equation of the transmission line to obtain the space point (x, y, z _k ) on the transmission line, and obtain the distance between two points in space from the three-dimensional coordinates:

The advantages of the present invention are:

1. Through the combination of Zhang's calibration method and self-calibration method, the internal parameters and external parameters of the system are calibrated before and after the erection of the binocular vision system, which solves the inconvenience of using traditional calibration methods after erection, and Only using the self-calibration method is not a high precision problem.

2. By establishing a database of three-dimensional coordinate points and corresponding distances in the monitoring area, the calculation of complex and lengthy three-dimensional reconstruction and space ranging in the detection is converted into a method of directly querying the database, which can greatly improve the detection speed and increase real-time performance.

Description of drawings

Fig. 1 is the schematic flow chart of three-dimensional coordinate point collection and monitoring space point-minimum distance database establishment among the present invention;

FIG. 2 is a schematic flow chart of foreign object intrusion detection and space ranging in the present invention.

detailed description

The technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention.

As shown in Figure 1, the specific three-dimensional monitoring area model establishment method is as follows:

Step P101: Before setting up the binocular vision system, in the laboratory, use the printed calibration plate of known size to collect images by rotating at least 3 angles, and use Zhang’s calibration method to determine the internal parameter α of the binocular vision system (scale factor on the x-axis), β (scale factor on the y-axis), γ (oblique factor of the image coordinates and the optical axis coordinates), μ (the position of the optical center of the optical axis on the x-axis of the image coordinates), υ (the position of the optical center of the optical axis on the image coordinate y-axis) for calibration;

Step P102: After step P101 is completed, erect the binocular vision system on the tower;

Step P103: After the binocular vision system is set up, use the self-calibration method to calibrate the external parameters R (rotation factor) and t (translation factor) of the binocular vision system through the video data collected by the left and right imaging systems in the system;

Step P104: select the area where the transmission line is connected to the tower, and the area with obvious geometric characteristics such as the lowest area of the sag of the transmission line as the rough selection area of feature points;

Step P105: According to the rough selection area of feature points selected in step P104, the feature points are precisely selected by matching the luminance value in the area in the left and right imaging of the binocular vision system.

Step P106: According to the feature points selected in step P105, and the internal and external parameters of the binocular vision system calibrated in steps P101 and P102, perform three-dimensional reconstruction on the matched feature points, and obtain the three-dimensional coordinates (x, y, z) of the feature points.

Step P107: According to the three-dimensional coordinates of multiple feature points matched in step P106, establish the spatial equation of the transmission line:

Where σ ₀ is the horizontal stress at each point of the wire, in N/mm ² ;

γ is the specific load of the wire, in N/m.mm ² ;

k is the horizontal distance from the wire suspension point to the origin, in m;

l _AO is the horizontal distance between the lowest point of the wire and the suspension point,

The unit is m;

l is the gear distance, the unit is m;

h is height difference, the unit is m.

Step P108: Based on the transmission line space equation established in step P107, determine the three-dimensional coordinates (x, y, z) of the intersection point of the transmission line space equation on a certain plane; set (x, y) of the three-dimensional coordinates of the intersection point as the center, Taking the distance a from the transmission line as the edge of the monitoring range, a plane monitoring area is established, and the range of the monitoring area on the x and y axes is:

(x-a)<x<(x+a),

(y-a)<y<(y+a)

Step P109: According to the range of x and y coordinates of the planar monitoring area established in step P108, and the range of values of the depth z of the transmission line space equation established in step P107, establish a set of three-dimensional coordinate points, that is, the three-dimensional monitoring area model of the transmission line .

Step P110: According to the set of three-dimensional coordinate points established in step P109, calculate the minimum distance value from the spatial point in the set to the spatial equation of the transmission line established in step P107. The minimum distance value is obtained from the spatial point and its nearest point on the transmission line. For the convenience of calculation, it is assumed that the monitoring point and the nearest point on the corresponding line have the same depth value, that is, their Z values are the same. The depth information z _k in the three-dimensional coordinates (x _k , y _k , z _k ) of the spatial point is brought into the spatial equation of the transmission line to obtain the spatial point (x, y, z _k ) on the transmission line, and the three-dimensional coordinates of the two spatial points Find the distance between them:

Step P111: According to the set of three-dimensional coordinate points in the three-dimensional monitoring model established in step P109 as monitoring data, and then according to the minimum distance value calculated in step P110, finally establish a database of the set of monitored spatial coordinates and the corresponding distance.

As shown in Figure 2, the specific monitoring process is as follows:

In daily monitoring, the detection starts at step M101, and the foreign object is first identified through step M102, and the feature points of the foreign object are selected (step M103), matched (step M104) and three-dimensionally reconstructed (step M105). Then, in step M106, the reconstructed three-dimensional coordinates of the foreign object are compared with the database.

In step M107, it is judged whether the three-dimensional coordinates of the foreign matter belong to the three-dimensional coordinate set in the database. If the judgment result is no, it means that the foreign matter is not in the three-dimensional monitoring area, and return to step M102 to re-enter the detection state; if the judgment result is yes, it means that the foreign matter has entered For the three-dimensional monitoring area, proceed to step M108, querying the distance between the foreign object coordinates and the power transmission line in the database.

In step M109, the corresponding distance between the judgment result in step M107 and the query in step M108 is issued, and an alarm is issued.

The above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any changes or substitutions that can be easily imagined by those skilled in the art within the technical scope disclosed in the present invention, All should be covered within the protection scope of the present invention.

Claims (7)

1. a kind of electric transmission line channel solid space monitoring and fast ranging method, it is characterised in that comprise the following steps：

(1) binocular vision system is demarcated, obtains binocular vision system inside and outside parameter；

(2) brightness value matches to obtain transmission line of electricity characteristic point in roughing region in being imaged by binocular vision system or so, then Three-dimensional reconstruction is carried out to the transmission line of electricity characteristic point after matching using the binocular vision system inside and outside parameter of demarcation, with cross arm of tower Center is origin, establishes three-dimensional coordinate system, tries to achieve characteristic point three-dimensional coordinate；

(3) transmission line of electricity space equation is established using the characteristic point three-dimensional coordinate of reconstruction；

(4) three-dimensional coordinate point set, the i.e. three-dimensional prison of transmission line of electricity are established by transmission line of electricity space equation and plane monitor area Control regional model；

(5) lowest distance value of all spatial points and transmission line of electricity space equation in three-dimensional coordinate point set is calculated；

(6) according to step (4) establish three-dimensional coordinate point set be monitoring data, according to step (5) calculating spatial point with it is defeated The lowest distance value of electric line space equation establishes monitoring mould of the hollow point of three-dimensional coordinate point set with corresponding lowest distance value Type database, i.e. monitoring space point-minimum range database；

(7) in daily monitoring, by detecting foreign matter characteristic point and rebuilding thirdly dimension coordinate, with the three-dimensional coordinate after reconstruction with not Monitoring space point-minimum range cdr database of step (6) structure is compared, and judges whether foreign matter enters alert zone Domain, and with a distance from can quickly estimating foreign matter from transmission line of electricity by database.

2. electric transmission line channel solid space monitoring as claimed in claim 1 and fast ranging method, it is characterised in that：It is described Step (1) binocular vision system demarcating steps are：Using Zhang Shi methods to binocular vision system before binocular vision system installation is set up Intrinsic parameter α, β, γ, μ, υ of system system are demarcated, wherein α be x-axis on scale factor, β be y-axis on scale factor, γ For image coordinate and the oblique factor of optical axis coordinate, μ is position of the optical axis photocentre in image coordinate x-axis, and υ is that optical axis photocentre exists Position in image coordinate y-axis；After binocular vision system is set up, outer parameter R, t using self-calibration method to binocular vision system Demarcated, wherein R is twiddle factor, and t is shift factor.

3. electric transmission line channel solid space monitoring as claimed in claim 1 and fast ranging method, it is characterised in that：It is described Transmission line of electricity characteristic point is chosen and concretely comprised the following steps in step (2)：The region with obvious geometric properties will be chosen first as spy Sign point roughing region, then characteristic point is carried out by brightness value matching in roughing region in binocular vision system or so imaging and accurately selected Take.

4. electric transmission line channel solid space monitoring as claimed in claim 3 and fast ranging method, it is characterised in that：It is described Region with obvious geometric properties is circuit and the join domain of shaft tower and the lowermost extent of power transmission line sag.

5. electric transmission line channel solid space monitoring as claimed in claim 1 and fast ranging method, it is characterised in that：It is described Step (3) establishes transmission line of electricity space equation using the characteristic point three-dimensional coordinate of reconstruction：

Wherein σ₀For electric wire each point horizontal stress, unit N/mm²；

γ is electric wire than load, unit N/m.mm²；

K is electric wire hitch point to the horizontal range of origin, unit m；

l_AOFor electric wire minimum point to horizontal range between hitch point electric wire,

Unit is m；

L is span, unit m；

H is the discrepancy in elevation, unit m.

6. electric transmission line channel solid space monitoring as claimed in claim 1 and fast ranging method, it is characterised in that：It is described The foundation of transmission line of electricity solid monitor area model in step (4), first based on transmission line of electricity space equation, it is determined that transmission of electricity The three-dimensional coordinate (x, y, z) of circuit space equation intersection point on a certain plane；Centered on (x, y) if of intersection point three-dimensional coordinate, with It is monitoring range edge from transmission line of electricity distance a, establishes plane monitor area, obtains scope of the monitor area on x and y-axis For：

(x-a) ＜ x ＜ (x+a),

(y-a) ＜ y ＜ (y+a)

Finally with the depth z value values of the x of plane monitor area and y coordinate span, and transmission line of electricity space equation Scope, three-dimensional coordinate point set is established, i.e., three-dimensional monitor area model.

7. electric transmission line channel solid space monitoring as claimed in claim 1 and fast ranging method, it is characterised in that：It is described Spatial point passes through the spatial point three-dimensional coordinate (x of reconstruction to the lowest distance value of transmission line of electricity space equation in step (5)_k, y_k, z_k), with z_kFor it is same monitoring plane depth information bring transmission line of electricity space equation into, obtain on transmission line of electricity spatial point (x, Y, z_k), distance therebetween is tried to achieve by 2, space three-dimensional coordinate：