CN111340891A - Method and system for calibrating camera by using LED screen - Google Patents
Method and system for calibrating camera by using LED screen Download PDFInfo
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- CN111340891A CN111340891A CN202010117326.8A CN202010117326A CN111340891A CN 111340891 A CN111340891 A CN 111340891A CN 202010117326 A CN202010117326 A CN 202010117326A CN 111340891 A CN111340891 A CN 111340891A
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- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
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- G06T7/80—Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
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Abstract
The invention belongs to the field of camera calibration, and particularly relates to a method and a system for calibrating a camera by using an LED screen, wherein the method comprises the following steps: receiving the size of the LED matrix picture, the light point arrangement information and the light point position information; determining the position information of four corner lamp points in the LED matrix picture according to the lamp point position information, and connecting the four corner lamp points to enclose a lamp point rectangular frame; acquiring position information of the lamp points on the four side frames according to the lamp point rectangular frame, the lamp point arrangement information and the lamp point position information; carrying out lamp point position sequencing according to the position information of the side lamp points, constructing a three-dimensional world coordinate sequence, and outputting a frame three-dimensional world coordinate sequence of four sides of a rectangular frame of the lamp points; and calibrating the camera according to the position information of the side lamp points of the four borders of the lamp point rectangular frame, the corresponding three-dimensional world coordinate sequence and the size of the LED matrix picture, and outputting the internal parameters, the external parameters and the distortion parameters of the camera. The invention can realize the real-time calibration of the camera and reduce the time cost and the workload of workers.
Description
Technical Field
The invention belongs to the field of camera calibration methods, and particularly relates to a method and a system for calibrating a camera by using an LED screen.
Background
In machine vision or image measurement, in order to determine the relationship between the three-dimensional coordinates of points on the surface of an object and the image points of an image of the object, a camera imaging geometric model must be established, and the process of solving the parameters of the geometric model is called camera calibration. Therefore, the camera calibration is a precondition for subsequent work, and the improvement of the calibration precision is a key point of scientific research. The common camera calibration method needs to take a certain number of calibration pictures at different positions, different angles and different postures, the calibration plate needs to be a chessboard diagram formed by black and white rectangles, and the manufacturing precision requirement is high; in addition, the traditional camera calibration method needs a client to send the calibration camera back to a company, and the calibration camera is sent back to the client after being calibrated, so that the time cost is high, a calibration plate needs to be manufactured to shoot calibration pictures, the workload of workers is increased, and the process is complicated.
Disclosure of Invention
In order to solve the problems in the background art, the invention provides a method and a system for calibrating a camera by using an LED screen, which can realize real-time calibration, can calibrate when software runs, and reduce time cost and workload of workers.
A first object of the present invention is to provide a method for camera calibration using an LED screen, the method comprising:
receiving the size of the LED matrix picture, the arrangement information (the number of the lamp points on the rows and the columns) of the lamp points and the position information of the lamp points;
determining the position information of four corner lamp points in the LED matrix picture according to the lamp point position information, and connecting the four corner lamp points to form a lamp point rectangular frame;
acquiring the position information of the lamp points on the four side frames according to the lamp point rectangular frame, the lamp point arrangement information and the lamp point position information;
carrying out lamp point position sequencing according to the position information of the side lamp points;
constructing a three-dimensional world coordinate sequence and outputting a frame three-dimensional world coordinate sequence of four sides of the rectangular frame of the lamp point;
and calibrating the camera according to the position information of the side lamp points on the four borders of the lamp point rectangular frame, the corresponding three-dimensional world coordinate sequence and the size of the LED matrix picture, and outputting the internal parameters, the external parameters and the distortion parameters of the camera.
Further, determining the position information of the four corner lamp points in the LED matrix picture according to the lamp point position information includes:
calculating the intercept of a first straight line with the slope of-1 and passing through a lamp point in the LED matrix picture, and determining the passed lamp point as an upper left lamp point and a lower right lamp point of the LED matrix when the intercept of the first straight line is minimum and maximum;
and calculating the intercept of a second straight line with the slope of 1 and passing through the lamp points, and determining the passed lamp points as the upper right corner lamp point and the lower left corner lamp point of the LED matrix when the intercept of the second straight line is minimum and maximum.
Further, according to the light point rectangular frame, the light point arrangement information and the light point position information, the position information of the side light points on the four frames is obtained, which includes:
carrying out Thiessen polygon subdivision on the rectangular frame area of the lamp points according to the position information of all the lamp points, and outputting the position information of the lamp points on the four frames in the rectangular frame of the lamp points;
calculating the normalized distance from the side light point to four borders of the light point rectangular frame; and when the normalized distance is minimum, determining that the side lamp points are positioned on the corresponding frame, and outputting the position information of the side lamp points on the four frames.
Further, the lamp point position sorting is performed according to the position information of the side lamp points, and the lamp point position sorting method includes the following steps:
taking the upper left corner lamp points of the four corner lamp points as an original point, taking the upper frame as an x axis, and taking the left frame as a y axis to establish a coordinate system;
sorting the side lamp point coordinates on the upper frame and the lower frame of the lamp point rectangular frame according to the size of an x coordinate value;
and sorting the side lamp point coordinates on the left frame and the right frame of the lamp point rectangular frame according to the size of the y coordinate value.
A second object of the present invention is to provide a system for camera calibration using an LED screen, comprising: the system comprises a light point matrix information acquisition module, an angle light point confirmation module, a light point sequencing module, a three-dimensional world coordinate sequence creation module and a camera calibration module; wherein the content of the first and second substances,
the lamp dot matrix information acquisition module is connected with the corner lamp dot confirmation module and receives the size of the LED matrix picture, the lamp dot arrangement information and the lamp dot position information;
the corner lamp point confirming module is connected with the lamp point matrix information acquiring module and the lamp point sequencing module, and is used for determining the position information of four corner lamp points in the LED matrix picture according to the lamp point position information and connecting the four corner lamp points to form a lamp point rectangular frame;
the lamp point sorting module is connected with the corner lamp point confirming module and the three-dimensional world coordinate sequence creating module and is used for acquiring the position information of the lamp points on the four side frames according to the lamp point rectangular frame, the lamp point arrangement information and the lamp point position information; carrying out lamp point position sequencing according to the position information of the side lamp points;
the three-dimensional world coordinate sequence creating module is connected with the lamp point sorting module and the camera calibration module and is used for constructing a three-dimensional world coordinate sequence according to the lamp point position sorting and outputting a frame three-dimensional world coordinate sequence of four sides of the lamp point rectangular frame;
and the camera calibration module is connected with the three-dimensional world coordinate sequence creation module and used for calibrating the camera according to the position information of the side lamp points on the four borders of the lamp point rectangular frame, the three-dimensional world coordinate sequence corresponding to the side lamp point position information and the size of the LED matrix picture, and outputting the internal parameters, the external parameters and the distortion parameters of the camera.
Further, the corner lamp point confirmation module includes: the device comprises a first corner lamp point confirming unit, a second corner lamp point confirming unit and a lamp point rectangular frame generating unit; wherein the content of the first and second substances,
the first corner lamp point confirming unit is connected with the lamp point matrix information acquisition module and the lamp point rectangular frame generating unit, calculates the intercept of a first straight line with the slope of-1 and passing through the lamp points in the LED matrix picture, and determines the passing lamp points to be the upper left corner lamp point and the lower right corner lamp point of the LED matrix when the intercept of the first straight line is minimum and maximum;
the second corner lamp point confirming unit is connected with the lamp point matrix information acquisition module and the lamp point rectangular frame generating unit, calculates the intercept of a second straight line with the slope of 1 and passing through the lamp points, and determines the passed lamp points to be the upper right corner lamp point and the lower left corner lamp point of the LED matrix when the intercept of the second straight line is minimum and maximum;
and the lamp point rectangular frame generating unit is connected with the first corner lamp point confirming unit, the second corner lamp point confirming unit and the lamp point sequencing module and is used for connecting the four corner lamp points to form a lamp point rectangular frame.
Further, the lamp point sorting module comprises a lamp point calculating unit and a side lamp point confirming unit, wherein,
the lamp point calculation unit is connected with the corner lamp point confirmation module and the side lamp point confirmation unit, carries out Thiessen polygon subdivision on the rectangular frame area of the lamp points according to the position information of all the lamp points, and outputs the position information of the lamp points on the four frames in the rectangular frame of the lamp points; calculating the normalized distance from the side lamp points to four borders of the lamp point rectangular frame, determining that the side lamp points are positioned on the corresponding borders when the normalized distance is minimum, and outputting the position information of the side lamp points on the four borders;
the side light point confirming unit is connected with the light point calculating unit and the three-dimensional world coordinate sequence creating module.
The lamp point sorting module further comprises a lamp point position information sorting unit, the lamp point position information sorting unit is connected with the side lamp point confirming unit, the upper left corner lamp point of the four corner lamp points is taken as an original point, the upper frame is an x axis, and the left frame is a y axis to establish a coordinate system;
sorting the side lamp point coordinates on the upper frame and the lower frame of the lamp point rectangular frame according to the size of an x coordinate value;
and sorting the side lamp point coordinates on the left frame and the right frame of the lamp point rectangular frame according to the size of the y coordinate value.
Compared with the prior art, the invention has the beneficial effects that: the camera calibration method provided by the invention has the advantages that the calibration plate is not required to be manufactured to shoot the calibration picture, the camera is directly utilized to shoot the lamp point coordinates on the LED screen box body to finish the real-time calibration of the camera, the calibration process is simpler, and the calibration process can be finished without a professional; in addition, because the calibration process does not need to find the grid angular points and fill in the coordinates of the angular points, the speed of the calibration process of the camera is higher, and the time cost and the labor cost of camera calibration are greatly reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic flowchart of a method for calibrating a camera by using an LED screen according to an embodiment of the present invention;
fig. 2 is a schematic flow chart illustrating a process of determining position information of four corner lamp points in an LED matrix picture in a camera calibration method using an LED screen according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a system for calibrating a camera by using an LED screen according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a second system for calibrating a camera by using an LED screen according to an embodiment of the present invention.
Fig. 5 is a schematic structural diagram of a third system for calibrating a camera by using an LED screen according to an embodiment of the present invention.
Fig. 6 is a schematic structural diagram of a fourth system for calibrating a camera by using an LED screen according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, an embodiment of the present invention provides a method for calibrating a camera by using an LED screen, where the method includes:
s100, receiving the size of the LED matrix picture, light point arrangement information (the number of light points on rows and columns) and light point position information;
in an embodiment, calibration software in the camera may store a program for implementing camera calibration by using an LED screen, when the camera calibration is required, an LED matrix picture is first taken, and the calibration software of the camera may calculate internal parameters, external parameters, and distortion parameters of the camera by using light points in the LED matrix picture, and finally complete the camera calibration.
S110, determining the position information of four corner lamp points in the LED matrix picture according to the lamp point position information, and connecting the four corner lamp points to form a lamp point rectangular frame;
in an embodiment, a coordinate system may be set to locate coordinates of the lamp points, the calibration software may identify all the coordinates of the lamp points, and initialize a program, and an operator may input a certain instruction to find coordinates of the four corner points, for example, by editing a certain program, a common method is for a round-robin determination, the coordinates of the lamp points are updated when conditions are satisfied, the four corner lamp points are found by comparing the coordinates of all the lamp points with each other, and the coordinates of the lamp points at the four corner lamp points form a rectangular frame of the lamp points. In brief, as shown in fig. 2, the process schematic diagram of determining the position information of the four corner lamp points in the LED matrix picture in the method for calibrating the camera by using the LED screen in the embodiment includes the following steps:
s111, calculating a first straight line intercept with a slope of-1 and passing through a lamp point, and determining the passed lamp point as an upper left corner lamp point and a lower right corner lamp point of the LED matrix when the first straight line intercept is minimum and maximum;
s112, calculating a second straight line intercept with the slope of 1 and passing through the lamp points, and determining the passed lamp points as the upper right corner lamp point and the lower left corner lamp point of the LED matrix when the second straight line intercept is minimum and maximum; the principle of finding four corner lamp points can be realized by editing a certain computer program.
It should be noted that the position information of the four corner points of the rectangular frame of the light point obtained by the above method is based on the premise that the coordinate origin of the image coordinate system is at the upper left corner, and increases progressively from left to right by x, and increases progressively from top to bottom by y.
S120, acquiring position information of the lamp points on the four side frames according to the lamp point rectangular frame, the lamp point arrangement information and the lamp point position information;
in the embodiment, a Thiessen polygon subdivision is carried out on the rectangular frame area of the lamp points according to the position information of all the lamp points, and the position information of the lamp points on the four borders in the rectangular frame of the lamp points is output;
specifically, in the embodiment, the upper left corner lamp point of the 4 corner lamp points is taken as the origin of the coordinate system, the upper frame side is taken as the x axis, and the left frame side is taken as y to calculate the normalized distance from the side lamp point to the four frames of the lamp point rectangular frame; when the normalized distance is minimum, determining that the side lamp points are positioned on the corresponding frame, and outputting the position information of the side lamp points on the four frames;
the coordinate system comprises an axis, an x-axis horizontal direction right horizontal coordinate is gradually increased, a y-axis vertical direction downward vertical coordinate is gradually increased, all lamp point coordinates, four corner lamp point coordinates, distances between four corner lamp points and an outermost lamp point rectangular frame are read in calibration software, whether a certain lamp point coordinate is located in the lamp point rectangular frame or not is judged, if the certain lamp point coordinate is located in the lamp point rectangular frame, all vertex coordinates of a Thiessen polygon are obtained by taking the lamp point coordinate as a sample point, all vertex coordinates are traversed to obtain the maximum distance value from a vertex to the lamp point, the maximum value of the lamp point is compared with a preset value (the set value is an empirical value determined according to experiments), if the maximum value of the lamp point is larger than the set value, the lamp point coordinate is located at a point on four frame sides of the lamp point rectangular frame, and finally all lamp point coordinates on the four frames of the lamp point rectangular frame are output;
in the embodiment, after the coordinates of the light points on the four borders of the light point rectangular frame are determined, it is further determined on which border of the light point rectangular frame a certain light point coordinate on the four borders is specifically located, the coordinates of the four corner light points, the distance between the four corner light points, and all the coordinates of the light points on the four borders of the light point rectangular frame are read in calibration software, whether the coordinates of the light points on the four borders are the corner light points is judged, if not, the distances from the coordinates of the light points to the four corner light points are respectively calculated, then, the normalized distances from the coordinates of the light points to the four borders of the light point rectangular frame are calculated, all the normalized distances are traversed to obtain the minimum distance value, which border of the light point rectangular frame the coordinates belong to is determined, and the information of the positions of the edge light points on each border of the four borders of the light point rectangular frame is.
It should be noted that: the specific process of calculating the normalized distance from a point to an edge is as follows: knowing the point p and the starting point a and the end point B of the edge, and expressing the distances from p to a and B as pA and pB, respectively, the edge length can be approximated as a distance AB from a to B, the normalized distance from a point to an edge can be expressed as:
dist＝(pA+pB)/AB
s130, carrying out lamp point position sequencing according to the position information of the side lamp points;
in the embodiment, a coordinate system is established by taking the upper left corner lamp points of the four corner lamp points as an origin, taking the upper frame as an x axis and taking the left frame as a y axis; sorting the side lamp point coordinates on the upper frame and the lower frame of the lamp point rectangular frame according to the size of an x coordinate value; and sorting the side lamp point coordinates on the left frame and the right frame of the lamp point rectangular frame according to the size of the y coordinate value.
Specifically, in the embodiment, the distance between the coordinates of the lamp points is a fixed value, that is, the unit length is a fixed value, the length value of one of the four borders of the rectangular frame of the lamp points and the ideal number of the lamp points are read, the unit length of the lamp points is calculated, the lamp points are sorted and numbered according to the unit length, in actual operation, the number of the lamp points on the LED screen is not completely sorted in an array, and an abnormal situation may occur, for example, the relative positions of two lamp points are relatively close, so that the numbers are repeated, at this time, the coordinates of the lamp points with repeated numbers and the corresponding numbers on the same border need to be removed, so as to obtain unique coordinates of the lamp points and the numbers of the coordinates of the lamp points, for example, the coordinates of three adjacent lamp points on the upper border are (1,0), (1.2,0) (1.3,0), and the corresponding unit length is 1, so that the numbers of the coordinates of the three lamp points are all defined as 1,0) and (1.3,0) two lamp point coordinates.
S140, constructing a three-dimensional world coordinate sequence and outputting a frame three-dimensional world coordinate sequence of four sides of the lamp point rectangular frame;
in the embodiment, a three-dimensional coordinate axis is established, the upper left corner point is used as an origin, the upper frame is used as an x axis, the left frame is used as a y axis, the value of the z axis is set to 0, the lamp point coordinate numbers, the row lamp point numbers and the column lamp point numbers of the four frames are read, the upper frame is selected firstly, a three-dimensional world coordinate sequence of the upper frame is constructed, and the three-dimensional coordinate axis is defined, wherein the three-dimensional coordinate of the upper frame is x which is the lamp point coordinate number on the upper frame, y which is 0, and z which is 0; selecting a vertical left frame, and constructing a three-dimensional world coordinate sequence of the left frame, wherein the three-dimensional coordinate of the left frame is x equal to 0, y equal to the coordinate number of a lamp point on the left frame, and z equal to 0; selecting a vertical right frame, constructing a three-dimensional world coordinate sequence of the right frame, wherein the three-dimensional coordinate of the right frame is x which is the number of rows of lamp points-1, y which is the number of lamp point coordinates on the right frame, and z which is 0, selecting a horizontal lower frame, constructing a three-dimensional world coordinate sequence of the lower frame, and then the three-dimensional coordinate of the lower frame is x which is the number of the lamp point coordinates on the lower frame, y which is the number of rows of lamp points-1, and z which is 0; and finally, outputting the three-dimensional world coordinate sequences of the four frames.
S150, calibrating the camera according to the position information of the side lamp points on the four borders of the lamp point rectangular frame, the three-dimensional world coordinate sequence corresponding to the position information and the size of the LED matrix picture, and outputting the internal parameters, the external parameters and the distortion parameters of the camera.
In the embodiment, according to the position information of the side lamp points on the four borders of the lamp point rectangular frame, the three-dimensional world coordinate sequences corresponding to the side lamp point position information and the size of the LED picture, the internal parameters, the external parameters and the distortion parameters of the camera are calculated by using a Zhang Yongyou calibration method, and the self-calibration of the camera is completed.
It should be noted that the zhangzhengyou calibration method is a camera calibration method of a single-plane checkerboard proposed by zhangzhengyou professor 1998, which is between the conventional calibration method and the self-calibration method, but overcomes the disadvantage of the high-precision calibration object required by the conventional calibration method, and only needs to use one printed checkerboard. Meanwhile, compared with self-calibration, the precision is improved, and the operation is convenient.
When the scheme provided by the embodiment of the invention is applied to camera calibration, a calibration plate is not required to be manufactured to shoot calibration pictures, the camera is directly used for shooting the coordinates of the lamp points on the LED screen box body or directly receiving shot LED rectangular pictures to finish the real-time calibration of the camera, the calibration process is simpler, and the calibration process can be finished without professional staff; in addition, because the calibration process does not need to find the grid angular points and fill in the coordinates of the angular points, the speed of the calibration process of the camera is higher, and the time cost and the labor cost of camera calibration are greatly reduced.
Referring to fig. 3, an embodiment of the present invention further provides a system for calibrating a camera by using an LED screen, where the system includes:
the system comprises a light point matrix information acquisition module 200, an angle light point confirmation module 210, a light point sorting module 220, a three-dimensional world coordinate sequence creation module 230 and a camera calibration module 240; wherein the content of the first and second substances,
the light point matrix information obtaining module 200 is connected to the corner light point confirming module 210, and first takes a picture of an LED matrix with a camera, and receives the size of the picture of the LED matrix, light point arrangement information, and light point position information;
the corner lamp point confirming module 210 is connected with the lamp point matrix information acquiring module 200 and the lamp point sorting module 220, and is configured to determine position information of four corner lamp points in the LED matrix picture according to the lamp point position information, and connect the four corner lamp points to form a lamp point rectangular frame;
the light point sorting module 220 is connected to the corner light point confirming module 210 and the three-dimensional world coordinate sequence creating module 230, and configured to obtain position information of the side light points on the four frames according to the light point rectangular frame, the light point arrangement information, and the light point position information; carrying out lamp point position sequencing according to the position information of the side lamp points;
the three-dimensional world coordinate sequence creating module 230 is connected to the light point sorting module 220 and the camera calibration module 240, and is configured to construct a three-dimensional world coordinate sequence according to the light point position sorting, and output a frame three-dimensional world coordinate sequence of four sides of the light point rectangular frame;
the camera calibration module 240 is connected to the three-dimensional world coordinate sequence creation module 230, and is configured to perform camera calibration according to the position information of the side light points on the four borders of the light point rectangular frame, the three-dimensional world coordinate sequence corresponding to the side light points, and the size of the LED matrix picture, and output internal parameters, external parameters, and distortion parameters of the camera.
In this embodiment, as shown in fig. 4, the corner lighting point confirmation module 210 includes: a first corner lighting point confirming unit 211, a second corner lighting point confirming unit 212, and a lighting point rectangular frame generating unit 213; wherein the content of the first and second substances,
the first corner lamp point confirming unit 211 is connected to the lamp point matrix information obtaining module 200 and the lamp point rectangular frame generating unit 213, calculates an intercept of a first straight line having a slope of-1 and passing through a lamp point in the LED matrix picture, and determines that the passed lamp point is an upper left corner lamp point and a lower right corner lamp point of the LED matrix when the intercept of the first straight line is minimum and maximum;
the second corner lamp point confirming unit 212 is connected to the lamp point matrix information obtaining module 200 and the lamp point rectangular frame generating unit 213, calculates an intercept of a second straight line having a slope of 1 and passing through a lamp point, and determines that the passed lamp point is an upper right corner lamp point and a lower left corner lamp point of the LED matrix when the intercept of the second straight line is minimum and maximum;
the light point rectangular frame generating unit 213 is connected to the first corner light point confirming unit 211, the second corner light point confirming unit 212, and the light point sorting module 220, and connects the four corner light points to form a light point rectangular frame.
In this embodiment, as shown in fig. 5, the light point sorting module 220 includes a light point calculating unit 221 and a side light point confirming unit 222, wherein,
the light point calculating unit 221 is connected to the corner light point confirming module 210 and the side light point confirming unit 222, performs thiessen polygon subdivision on the light point rectangular frame area according to the position information of all the light points, and outputs the position information of the light points on the four frames in the light point rectangular frame; calculating the normalized distance from the side lamp points to four borders of the lamp point rectangular frame, determining that the side lamp points are positioned on the corresponding borders when the normalized distance is minimum, and outputting the position information of the side lamp points on the four borders;
the side light point confirming unit 222 is connected to the light point calculating unit 221 and the three-dimensional world coordinate sequence creating module 230.
In this embodiment, as shown in fig. 6, the light point sorting module further includes a light point position information sorting unit 223, where the light point position information sorting unit 223 is connected to the side light point confirming unit 222, and a coordinate system is created by taking the upper left corner light point of the four corner light points as an origin, the upper frame as an x axis, and the left frame as a y axis;
sorting the side lamp point coordinates on the upper frame and the lower frame of the lamp point rectangular frame according to the size of an x coordinate value;
and sorting the side lamp point coordinates on the left frame and the right frame of the lamp point rectangular frame according to the size of the y coordinate value.
The light point position information sorting unit 223 is connected to the side light point confirming unit 222 and the three-dimensional world coordinate sequence creating module 230.
When the scheme provided by the embodiment of the invention is applied to camera calibration, a calibration plate is not required to be manufactured to shoot calibration pictures, the camera is directly used for shooting the coordinates of the lamp points on the LED screen box body or directly receiving shot LED rectangular pictures to finish the real-time calibration of the camera, the calibration process is simpler, and the calibration process can be finished without professional staff; in addition, because the calibration process does not need to find the grid angular points and fill in the coordinates of the angular points, the speed of the calibration process of the camera is higher, and the time cost and the labor cost of camera calibration are greatly reduced.
The present invention has been further described with reference to specific embodiments, but it should be understood that the detailed description should not be construed as limiting the spirit and scope of the present invention, and various modifications made to the above-described embodiments by those of ordinary skill in the art after reading this specification are within the scope of the present invention.
Claims (8)
1. A method for camera calibration using an LED screen, the method comprising:
receiving the size of the LED matrix picture, the light point arrangement information and the light point position information;
determining the position information of four corner lamp points in the LED matrix picture according to the lamp point position information, and connecting the four corner lamp points to form a lamp point rectangular frame;
acquiring the position information of the lamp points on the four side frames according to the lamp point rectangular frame, the lamp point arrangement information and the lamp point position information;
carrying out lamp point position sequencing according to the position information of the side lamp points;
constructing a three-dimensional world coordinate sequence and outputting a frame three-dimensional world coordinate sequence of four sides of the rectangular frame of the lamp point;
and calibrating the camera according to the position information of the side lamp points on the four borders of the lamp point rectangular frame, the corresponding three-dimensional world coordinate sequence and the size of the LED matrix picture, and outputting the internal parameters, the external parameters and the distortion parameters of the camera.
2. The method of claim 1, wherein determining the position information of the four corner lamp points in the LED matrix picture according to the lamp point position information comprises:
calculating the intercept of a first straight line with the slope of-1 and passing through a lamp point in the LED matrix picture, and determining the passed lamp point as an upper left lamp point and a lower right lamp point of the LED matrix when the intercept of the first straight line is minimum and maximum;
and calculating the intercept of a second straight line with the slope of 1 and passing through the lamp points, and determining the passed lamp points as the upper right corner lamp point and the lower left corner lamp point of the LED matrix when the intercept of the second straight line is minimum and maximum.
3. The method for calibrating a camera by using an LED screen according to claim 1, wherein the step of obtaining the position information of the lamp points on the four borders according to the rectangular frame of the lamp points, the arrangement information of the lamp points and the position information of the lamp points comprises the following steps:
carrying out Thiessen polygon subdivision on the rectangular frame area of the lamp points according to the position information of all the lamp points, and outputting the position information of the lamp points on the four frames in the rectangular frame of the lamp points;
calculating the normalized distance from the side light point to four borders of the light point rectangular frame; when the normalized distance is minimum, determining that the side lamp point is positioned on the corresponding frame;
and outputting the position information of the lamp points on the four frames.
4. The method for camera calibration with an LED screen according to claim 1, wherein the lamp position sorting according to the position information of the side lamp comprises:
taking the upper left corner lamp points of the four corner lamp points as an original point, taking the upper frame as an x axis, and taking the left frame as a y axis to establish a coordinate system;
sorting the side lamp point coordinates on the upper frame and the lower frame of the lamp point rectangular frame according to the size of an x coordinate value;
and sorting the side lamp point coordinates on the left frame and the right frame of the lamp point rectangular frame according to the size of the y coordinate value.
5. A system for camera calibration using an LED screen, comprising: the system comprises a light point matrix information acquisition module, an angle light point confirmation module, a light point sequencing module, a three-dimensional world coordinate sequence creation module and a camera calibration module; wherein the content of the first and second substances,
the lamp dot matrix information acquisition module is connected with the corner lamp dot confirmation module and receives the size of the LED matrix picture, the lamp dot arrangement information and the lamp dot position information;
the corner lamp point confirming module is connected with the lamp point matrix information acquiring module and the lamp point sequencing module, and is used for determining the position information of four corner lamp points in the LED matrix picture according to the lamp point position information and connecting the four corner lamp points to form a lamp point rectangular frame;
the lamp point sorting module is connected with the corner lamp point confirming module and the three-dimensional world coordinate sequence creating module and is used for acquiring the position information of the lamp points on the four side frames according to the lamp point rectangular frame, the lamp point arrangement information and the lamp point position information; carrying out lamp point position sequencing according to the position information of the side lamp points;
the three-dimensional world coordinate sequence creating module is connected with the lamp point sorting module and the camera calibration module and is used for constructing a three-dimensional world coordinate sequence according to the lamp point position sorting and outputting a frame three-dimensional world coordinate sequence of four sides of the lamp point rectangular frame;
and the camera calibration module is connected with the three-dimensional world coordinate sequence creation module and used for calibrating the camera according to the position information of the side lamp points on the four borders of the lamp point rectangular frame, the three-dimensional world coordinate sequence corresponding to the side lamp point position information and the size of the LED matrix picture, and outputting the internal parameters, the external parameters and the distortion parameters of the camera.
6. The system for camera calibration with an LED screen of claim 5, wherein the corner light point confirmation module comprises: the device comprises a first corner lamp point confirming unit, a second corner lamp point confirming unit and a lamp point rectangular frame generating unit; wherein the content of the first and second substances,
the first corner lamp point confirming unit is connected with the lamp point matrix information acquisition module and the lamp point rectangular frame generating unit, calculates the intercept of a first straight line with the slope of-1 and passing through the lamp points in the LED matrix picture, and determines the passing lamp points to be the upper left corner lamp point and the lower right corner lamp point of the LED matrix when the intercept of the first straight line is minimum and maximum;
the second corner lamp point confirming unit is connected with the lamp point matrix information acquisition module and the lamp point rectangular frame generating unit, calculates the intercept of a second straight line with the slope of 1 and passing through the lamp points, and determines the passed lamp points to be the upper right corner lamp point and the lower left corner lamp point of the LED matrix when the intercept of the second straight line is minimum and maximum;
and the lamp point rectangular frame generating unit is connected with the first corner lamp point confirming unit, the second corner lamp point confirming unit and the lamp point sequencing module and is used for connecting the four corner lamp points to form a lamp point rectangular frame.
7. The system for camera calibration with an LED screen according to claim 5, wherein the light point sorting module comprises a light point calculating unit and a side light point confirming unit, wherein,
the lamp point calculation unit is connected with the corner lamp point confirmation module and the side lamp point confirmation unit, carries out Thiessen polygon subdivision on the rectangular frame area of the lamp points according to the position information of all the lamp points, and outputs the position information of the lamp points on the four frames in the rectangular frame of the lamp points; calculating the normalized distance from the side lamp points to four borders of the lamp point rectangular frame, determining that the side lamp points are positioned on the corresponding borders when the normalized distance is minimum, and outputting the position information of the side lamp points on the four borders;
the side light point confirming unit is connected with the light point calculating unit and the three-dimensional world coordinate sequence creating module.
8. The system for calibrating a camera by using an LED screen according to claim 7, wherein the light point sequencing module further comprises a light point position information sequencing unit, the light point position information sequencing unit is connected with the side light point confirming unit, and a coordinate system is created by taking the upper left corner light point of the four corner light points as an origin, the upper frame as an x-axis and the left frame as a y-axis;
sorting the side lamp point coordinates on the upper frame and the lower frame of the lamp point rectangular frame according to the size of an x coordinate value;
and sorting the side lamp point coordinates on the left frame and the right frame of the lamp point rectangular frame according to the size of the y coordinate value.
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