CN113188524B - Parallelogram coding sign based on graphic geometric relation and coding method thereof - Google Patents

Parallelogram coding sign based on graphic geometric relation and coding method thereof Download PDF

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CN113188524B
CN113188524B CN202110397418.0A CN202110397418A CN113188524B CN 113188524 B CN113188524 B CN 113188524B CN 202110397418 A CN202110397418 A CN 202110397418A CN 113188524 B CN113188524 B CN 113188524B
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coding
pattern
combination
quadrilateral
code
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CN113188524A (en
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朱华炳
杨昭辉
殷玉龙
杨霈
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Hefei University of Technology
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Hefei University of Technology
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C15/00—Surveying instruments or accessories not provided for in groups G01C1/00 - G01C13/00
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C11/00—Photogrammetry or videogrammetry, e.g. stereogrammetry; Photographic surveying
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C25/00—Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass

Abstract

The invention discloses a parallelogram coding mark based on a graph geometric relation and a coding method thereof, wherein the quadrilateral coding mark comprises a quadrilateral background pattern and a coding pattern, the coding pattern is arranged in the quadrilateral background pattern and comprises a positioning pattern, an orientation pattern and a coding combination pattern, the orientation pattern and the positioning pattern are used for judging the direction of the quadrilateral coding mark, and the coding combination pattern is used for coding four corner points of the quadrilateral coding mark. The positions of all the coding combination patterns are distinguished by using a vector product method through the principle of geometric relationship, so that the digital image processing is easy, the affine transformation image can have good stability, and the coding information capacity is large; the extraction of sub-pixel level image coordinates can be realized, and when a visual structured light method is used for three-dimensional measurement, the quadrangle coding mark can be used for realizing three-dimensional point cloud splicing of a large-size target or camera parameter calibration under a large view field scene.

Description

Parallelogram coding mark based on graphic geometric relation and coding method thereof
Technical Field
The invention relates to the field of vision measurement in computer vision, in particular to a coding method of a quadrilateral coding mark based on a geometric relation of graphs, which is suitable for the fields of camera calibration, target feature extraction, stereo matching, three-dimensional data splicing and the like.
Background
In visual measurement, feature identification and matching of measured objects are one of the research hotspots in the field. However, under the condition of a high-resolution large field of view or other complex backgrounds, the accuracy of feature extraction and matching cannot meet the precision requirement, and the speed and precision of the current feature extraction and matching can be greatly improved by arranging the coding marks on the surface of the measured object, and meanwhile, the problem of matching of multiple images can be solved. Therefore, the design and identification of the coded mark is a key element in the visual measurement.
In 1972, Russo and Knockeart realized compilation and recognition by using unique characteristics of marker points, and since then, technology for encoding marker points has been rapidly developed. In order to meet the requirements of industrial measurement, a plurality of types of coding mark points are available, but most of the coding mark points are annular, circular or fan-shaped, and the coding mark points have the following defects: when the shooting angle changes, part of the codes deform, thereby influencing the precision; the capacity of the code is small, and the code cannot be used for a target with a large size.
Disclosure of Invention
The invention aims to overcome the defects of the existing coding mark, provides a coding method of a quadrilateral coding mark based on a graphic geometric relation, is suitable for multi-view stereoscopic vision calibration under a large field of view, has good stability on affine transformation images, has large coding capacity, and can also have higher coding precision and accuracy for targets with larger sizes.
In order to realize the effect, the invention adopts the technical scheme that:
a parallelogram coding mark based on a geometric relationship of a graph is a square coding square, a quadrilateral background pattern and a coding pattern are arranged on the surface of the coding square, and the coding pattern is positioned inside the quadrilateral background pattern;
the encoding patterns comprise positioning patterns, orientation patterns and encoding combination patterns, the orientation patterns and the positioning patterns are used for judging the directions of the quadrilateral encoding marks, and the encoding combination patterns are used for encoding each corner point of the quadrilateral encoding marks.
Furthermore, the number of the coding combination patterns is four, and each coding combination pattern is composed of one coding combination orientation pattern and three coding combination coding patterns.
Further, the positioning pattern, the orientation pattern, each code combined orientation pattern and each code combined code pattern are not overlapped and not communicated.
Furthermore, the colors of the orientation pattern, the positioning pattern, the coding combination orientation pattern and the coding combination coding pattern are the same, and are obviously different from the color of the quadrilateral background pattern.
Further, the area of any one of the encoding combination encoding patterns is smaller than that of any one of the orientation patterns, and the area of any one of the encoding combination orientation patterns is smaller than that of any one of the encoding combination encoding patterns.
Furthermore, a connecting line segment of the geometric center of the orientation pattern and the geometric center of the positioning pattern is connected with one side of the coding square, and the middle point of the connecting line segment is adjacent to/coincided with the geometric center point of the coding square.
Furthermore, four corners of the quadrilateral background pattern are divided into four regions, each region is provided with one coding combination pattern, and the geometric center of each coding combination orientation pattern is adjacent to/superposed with the geometric center of the region where the coding combination orientation pattern is located.
8. A quadrilateral coded marker according to claim 2 or 7, wherein: within each code combination pattern, the positions of the three code combination code patterns satisfy the formula:
Figure BDA0003019078300000021
wherein:
Figure BDA0003019078300000022
there is a significant difference in die length or direction;
n is the code number of the quadrilateral coding mark, N is a positive integer, and N belongs to [0,4095 ];
y is the code number of the code pattern in each region, and Y is 1,2,3, 4;
αNa standard vector resulting from directing the geometric center of the positioning pattern to the geometry of the orientation pattern;
Figure BDA0003019078300000023
the geometric centers of the orientation patterns are directed to the resulting vectors of the geometric centers of the three encoding combination encoding patterns, respectively.
The method for coding the parallelogram coding mark based on the graph geometric relationship comprises the following steps:
s10: the coding number of the quadrilateral coding mark is marked as N, N is a positive integer, and N belongs to [0,4095 ]. Establishing a coding coordinate system of a quadrilateral coding mark with a coding number N;
s20: selecting one vertex as the first vertex in the coding coordinate system
Figure BDA0003019078300000024
With the first vertex
Figure BDA0003019078300000025
Taking the direction of the quadrilateral coding mark as a starting point, and sequentially marking the other three vertexes of the quadrilateral coding mark as second vertexes along the clockwise direction by taking the human face as the front view
Figure BDA0003019078300000031
Third vertex
Figure BDA0003019078300000032
And a fourth vertex
Figure BDA0003019078300000033
S30: putting the first vertex
Figure BDA0003019078300000034
The first vertex
Figure BDA0003019078300000035
Second vertex
Figure BDA0003019078300000036
Third vertex
Figure BDA0003019078300000037
And a fourth vertex
Figure BDA0003019078300000038
Sequentially used as the first corner point of the quadrilateral coding mark with the number N corresponding to
Figure BDA0003019078300000039
Second corner point
Figure BDA00030190783000000310
The third corner
Figure BDA00030190783000000311
The fourth corner point
Figure BDA00030190783000000312
S40: divide the quadrilateral grid into four areas
Figure BDA00030190783000000313
S50: in the quadrilateral coding mark with the serial number N, the four coding combination orientation patterns are respectively positioned in the four regions, and the geometric center of each coding combination orientation pattern is adjacent to or coincided with the geometric center of the region where the pattern is positioned, so that the sequence of the four coding combinations is determined;
s60: in each area
Figure BDA00030190783000000314
In which the orientation pattern is combined by the codes in the corresponding regions
Figure BDA00030190783000000315
Has a geometric center of
Figure BDA00030190783000000316
Starting from three coded combined coded patterns respectively
Figure BDA00030190783000000317
The geometric center of (A) is sequentially
Figure BDA00030190783000000318
Figure BDA00030190783000000319
Constructing vectors
Figure BDA00030190783000000320
Vector
Figure BDA00030190783000000321
Vector
Figure BDA00030190783000000322
Wherein, Y is 1,2,3, 4;
differentiating vectors
Figure BDA00030190783000000323
Vector
Figure BDA00030190783000000324
Vector
Figure BDA00030190783000000325
To determine the size and direction of the three code pattern combinations
Figure BDA00030190783000000326
Sorting of (1);
s70: combining the Y-th code with the K-th code to form a code pattern in the quadrilateral code mark with the code number N
Figure BDA00030190783000000327
The corresponding code value is noted as
Figure BDA00030190783000000328
Wherein Y is 1,2,3,4, K is 1,2,3, and
Figure BDA00030190783000000329
is 0 or 1;
s80: for the quadrilateral coding mark with the coding number of N, the 12-bit binary number with the coding number of N is marked as wNAnd define
Figure BDA00030190783000000330
Respectively corresponding to binary numbers w in sequence from the lowest order to the highest orderNAnd must satisfy the following formula:
GN·FN＝N
wherein: column vector GN＝(20,21,22,23,24,25,26,27,28,29,210,211)T；
Column vector
Figure BDA00030190783000000331
S90: according to the Kth encoding combination encoding pattern of the Yth encoding combination in the quadrilateral encoding mark with the encoding number determined in the step S80 and corresponding to the N
Figure BDA00030190783000000332
Corresponding code value
Figure BDA00030190783000000333
Determining the corresponding coded combined coding pattern
Figure BDA0003019078300000041
The color of (c).
There is also provided a computer-readable storage medium comprising a computer program for use in conjunction with an electronic device having image processing capabilities, the computer program being executable by a processor to perform the encoding method.
Compared with the prior art, the invention has the following beneficial effects:
1. the parallelogram coding mark provided by the invention comprises four coding combination patterns, and each coding combination pattern comprises three coding combination coding patterns. Therefore, 4096 different codes can be generated by the quadrilateral coding mark provided by the invention, the coding capacity is large, the three-dimensional data can be well spliced aiming at a field target with a large size, and the high accuracy can be kept;
2. in the parallelogram coding mark provided by the invention, the positions of the orientation pattern, the positioning pattern and each coding combination pattern and the positions of each coding combination coding pattern are distinguished by a method of graphic geometric relationship and vector product, so that the parallelogram coding mark has stronger robustness and can also have higher precision aiming at affine transformation images;
3. the parallelogram coding mark provided by the invention has simple patterns, is easy to realize by extracting real-time digital images in computer vision measurement and decoding algorithm of the real-time quadrilateral coding mark, reduces the complexity of the calibration process, and can keep higher precision;
4. the parallelogram coding mark provided by the invention utilizes four vertexes of the parallelogram coding mark as four angular points, when one quadrangle coding mark is coded, four characteristic angular points containing coding information can be obtained, the establishment of a plurality of characteristic angular points is beneficial to extraction and high-precision positioning, and the parallelogram coding mark has larger application space in the aspects of high-precision quadrangle coding mark positioning, high-precision three-dimensional point cloud splicing and the like.
Drawings
FIG. 1 is a diagram of a quadrilateral code symbol when all code combination code patterns are white;
FIG. 2 is a schematic diagram of arrangement of each vertex, each corner point, and each coding pattern in each coding combination in the quadrilateral coding mark of the present invention;
FIG. 3 is a schematic diagram showing the arrangement of the vertices, corners and the coding patterns in the coding combinations in the quadrilateral coding marks with the coding numbers of 757;
FIG. 4 is a diagram illustrating the final effect of the quadrilateral code flag with code number 757;
FIG. 5 is a flowchart illustrating an encoding method according to the present invention.
Detailed Description
The following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings, will make the advantages and features of the present invention more comprehensible to those skilled in the art, and will thus provide a clear and concise definition of the scope of the present invention.
Referring to fig. 1, a parallelogram coding mark based on geometric relationship of figures is a square coding grid with a side length of 60 mm. The quadrilateral coding mark is composed of a square background pattern and a coding pattern, wherein the coding pattern is arranged inside the square background pattern. The coding pattern comprises a positioning pattern, an orientation pattern and a coding combination pattern, wherein the orientation pattern and the positioning pattern are used for judging the direction of the quadrilateral coding mark. The square background pattern has four coding combination patterns inside, each coding combination pattern is composed of 1 coding combination orientation pattern and 3 coding combination coding patterns, and the coding combination patterns are used for coding 4 vertexes of the quadrilateral coding mark.
The color of a square background pattern in the quadrilateral coding mark is marked as color 1, and the colors of an orientation pattern, a positioning pattern, all coding combination orientation patterns and all coding combination coding patterns in the quadrilateral coding mark are color 2. Wherein, the color 1 and the color 2 have obvious color difference. In this embodiment, it is preferable that color 1 is black and color 2 is white, as shown in fig. 1.
Inside the quadrilateral code mark, the area sizes of the orientation pattern, all code combination orientation patterns and all code combination code patterns satisfy the following relationship: the area of any one of the coding combination coding patterns is smaller than that of any one of the orientation patterns, and the area of any one of the coding combination orientation patterns is smaller than that of any one of the coding combination coding patterns. In this embodiment, the orientation pattern is a circular connected domain with a diameter of 12 mm, the encoding combination orientation pattern is a circular connected domain with a diameter of 3 mm, the encoding combination encoding pattern is a circular connected domain with a diameter of 6 mm, and the positioning pattern is a circular connected domain with an outer circle diameter of 12 mm and an inner circle diameter of 5 mm, as shown in fig. 1.
In this embodiment, the positioning pattern, the orientation pattern, all the encoding combination orientation patterns and all the encoding combination encoding patterns of the quadrilateral encoding mark are not overlapped and not communicated.
The coding number of the quadrilateral coding mark is marked as N, N is a positive integer, and N belongs to [0,4095]]. As shown in FIG. 2 (color 1 is set to gray in the figure for convenience of marking and description), inside the quadrangular code mark, the positioning pattern is marked as
Figure BDA0003019078300000051
With a geometric centre of1With an orientation pattern of
Figure BDA0003019078300000052
With a geometric centre of2From a to a1Starting from lead to a2Is marked as a standard vector alphaNRecord of a1And a2The line segment between is line segment lN. Segment lNRespectively, with four sides of the square lattice (shown in the figure)
Figure BDA0003019078300000053
) (q is shown in the figure)1'、q'2、q'3、q'4) Are connected to form four line segments (shown in the figure)
Figure BDA0003019078300000054
) The resulting four line segments divide the entire square grid into four regions (shown in the figure)
Figure BDA0003019078300000055
Wherein, Y is 1,2,3,4 respectively, which are the same below and are not repeated herein).
Then orient the pattern
Figure BDA0003019078300000056
And positioning pattern
Figure BDA0003019078300000057
The position of (a) should satisfy the following requirements: line segment lNMust be aligned with one side of the square lattice and line segment lNThe midpoint of (a) needs to be near (adjacent to or coincident with) the geometric center point of the square lattice; the positions of the four code combinations need to satisfy the following requirements: four coded combined orientation patterns are located inside the four zones, respectively, and the geometric center of each coded combined orientation pattern is near (adjacent to or coincident with) the geometric center point of the zone in which it is located. In this embodiment, line segment lNThe middle point of (3) coincides with the geometric center point of the square lattice, and the geometric centers of the four coded combined orientation patterns coincide with the geometric center point of the located area.
And, among the four vertexes of the square lattice, each vertex has and only has one encoding combination orientation pattern closest to the vertex, that is, among the straight line distances between each vertex and the geometric centers of the four encoding combination orientation patterns, there is and only one encoding combination orientation pattern with the shortest straight line distance. Meanwhile, two of the four encoding combination orientation patterns are significantly closer to the orientation pattern than to the positioning pattern. Likewise, the other two encoded combined orientation patterns are located significantly closer to the positioning pattern than to the orientation pattern.
As shown in fig. 2, each region
Figure BDA0003019078300000061
The code serial number of the code combination pattern in the corresponding area is marked as Y, and the code combination orientation pattern in the corresponding area is marked as
Figure BDA0003019078300000062
With a geometric centre of
Figure BDA0003019078300000063
In the Y-th code combination, the code combination code in the corresponding area is recordedThe pattern is sequentially
Figure BDA0003019078300000064
Corresponding geometric centers are sequentially
Figure BDA0003019078300000065
By
Figure BDA0003019078300000066
Respectively leading to
Figure BDA0003019078300000067
Three directional line segments are obtained and are respectively marked as vectors
Figure BDA0003019078300000068
Vector
Figure BDA0003019078300000069
Vector
Figure BDA00030190783000000610
Simultaneous vector
Figure BDA00030190783000000611
Vector
Figure BDA00030190783000000612
Vector
Figure BDA00030190783000000613
Respectively with the standard vector alphaNAre respectively recorded as
Figure BDA00030190783000000614
Figure BDA00030190783000000615
As shown in formula (1):
Figure BDA00030190783000000616
then each oneThe positions of the 3 code pattern code combinations within a code combination need to satisfy the following requirements:
Figure BDA00030190783000000617
there is a significant difference in the modular length or direction, which facilitates distinguishing the positions of the 3 code combining code patterns.
In the present embodiment, the pattern is oriented
Figure BDA00030190783000000618
A center of a circle2And positioning pattern
Figure BDA00030190783000000619
A center of a circle1Connected line segment lNThe length is 20 mm, and the central point of the line segment is superposed with the geometric central point of the square lattice; center of circle of four coding combined directional pattern
Figure BDA00030190783000000620
All coincide with the geometric center of the area; the center of each of the three code combination code patterns
Figure BDA00030190783000000621
Uniformly distributed in the center of a circle with the diameter of 9 mm and the respective coding combination orientation pattern
Figure BDA00030190783000000622
On coinciding circumferences, while one of the code patterns is combined with the code (as shown in FIG. 2)
Figure BDA00030190783000000623
) Center of circle and coding combined orientation pattern
Figure BDA0003019078300000071
Center of a circle
Figure BDA0003019078300000072
Is located atNAnd the center of the coding combination coding pattern is determined by the coding combinationTowards the center of the pattern and above the center of the circle.
Referring to fig. 5, a method for encoding a parallelogram encoding flag based on geometric relationship of figures is used to complete the encoding process of the encoding flag. The process is described in detail below with reference to a specific example.
The encoding method includes the steps of:
s10: the coding number of the quadrilateral coding mark is marked as N, N is a positive integer, and N belongs to [0,4095 ]. Establishing a coding coordinate system of a quadrilateral coding mark with a coding number N, which comprises the following specific processes:
s101: selecting one vertex on the quadrilateral coding mark with the coding number N as an origin o of a coding coordinate systemNWith the standard vector αNIs used as Y of the coding coordinate system of the quadrilateral coding mark with the coding number of NNThe positive direction of the axis;
s102: in the plane of the quadrilateral coding mark with the coding number N, the origin o of the coding coordinate system is usedNTaking Y as the rotation center and looking at the direction of the quadrilateral code mark in front of human bodyNClockwise rotates 90 degrees in the positive direction of the shaft, and the direction obtained after the rotation is taken as X of the coding coordinate systemNThe positive direction of the axis;
S103：XNaxis and YNAll the axes are in the plane of the quadrilateral coding mark, and the Z of the coding coordinate system is determined by adopting the right-hand ruleNThe axes are positive, thereby establishing a coding coordinate system oN-XNYNZNAs shown in fig. 2;
in this embodiment, if N is 757, the coding coordinate system o of the quadrilateral coding flag corresponding to the coding number 757 is taken as the coding coordinate system757-X757Y757Z757As shown in fig. 3.
S20: in the coding coordinate system, one vertex is selected to be marked as a first vertex
Figure BDA0003019078300000073
With the first vertex
Figure BDA0003019078300000074
Taking the direction of the quadrilateral coding mark as a starting point, and sequentially marking the other three vertexes of the quadrilateral coding mark as second vertexes along the clockwise direction by taking the human face as the front view
Figure BDA0003019078300000075
Third vertex
Figure BDA0003019078300000076
And a fourth vertex
Figure BDA0003019078300000077
In this embodiment, the origin o of the coding coordinate system is preferably set toNAs the first vertex
Figure BDA0003019078300000078
The first vertex
Figure BDA0003019078300000079
Second vertex
Figure BDA00030190783000000710
Third vertex
Figure BDA00030190783000000711
And a fourth vertex
Figure BDA00030190783000000712
The position of (a) should satisfy the following conditions: from the first vertex
Figure BDA00030190783000000713
Pointing to the second vertex
Figure BDA00030190783000000714
Vector of (2)
Figure BDA00030190783000000715
Is directed to the standard vector alphaNIs in the same direction and is formed by the second vertex
Figure BDA00030190783000000716
Pointing to the third vertex
Figure BDA00030190783000000717
Vector of (2)
Figure BDA00030190783000000718
Is directed to the standard vector alphaNThe same direction is also used;
in this embodiment, if N is 757, the four vertices of the quadrilateral code flag with the code number of 757 are assigned
Figure BDA0003019078300000081
Figure BDA0003019078300000082
As shown in fig. 3.
S30: putting the first vertex
Figure BDA0003019078300000083
The first vertex
Figure BDA0003019078300000084
Second vertex
Figure BDA0003019078300000085
Third vertex
Figure BDA0003019078300000086
And a fourth vertex
Figure BDA0003019078300000087
Sequentially as the first corner point of the quadrilateral coding mark with the number N corresponding to
Figure BDA0003019078300000088
Second corner point
Figure BDA0003019078300000089
The third corner
Figure BDA00030190783000000810
The fourth corner point
Figure BDA00030190783000000811
As shown in fig. 2;
in this embodiment, if N is 757, the first corner of the coding flag corresponding to the coding number 757 is taken as the first corner
Figure BDA00030190783000000812
Second corner point
Figure BDA00030190783000000813
Third corner
Figure BDA00030190783000000814
The fourth corner point
Figure BDA00030190783000000815
As shown in fig. 3.
S40: from the first vertex
Figure BDA00030190783000000816
Second vertex
Figure BDA00030190783000000817
Third vertex
Figure BDA00030190783000000818
And a fourth vertex
Figure BDA00030190783000000819
The four sides of the quadrilateral coding mark with the serial number of N corresponding to the sequentially connected directions are sequentially the sides
Figure BDA00030190783000000820
Edge
Figure BDA00030190783000000821
Edge
Figure BDA00030190783000000822
Edge
Figure BDA00030190783000000823
And note the edge
Figure BDA00030190783000000824
Edge
Figure BDA00030190783000000825
Edge
Figure BDA00030190783000000826
Edge
Figure BDA00030190783000000827
Is q 'in sequence'1、q′2、q′3、q′4(ii) a The standard vector alpha isNMidpoint p ofNAre respectively reacted with q'1、q′2、q′3、q′4Connecting to obtain line segments as dividing lines
Figure BDA00030190783000000828
Then four dividing lines
Figure BDA00030190783000000829
Divide the quadrilateral grid into four regions
Figure BDA00030190783000000830
In this embodiment, if N is 757, four regions of the coding flag corresponding to the coding number 757 are coded
Figure BDA00030190783000000831
Figure BDA00030190783000000832
As shown in fig. 3.
S50: remember four regions
Figure BDA00030190783000000833
Respectively has a geometric center point of o1、o2、o3、o4The code combined orientation pattern in the corresponding area is sequentially recorded as
Figure BDA00030190783000000834
Corresponding geometric centers are in turn
Figure BDA00030190783000000835
Figure BDA00030190783000000836
Then in the quadrilateral code mark with the number N corresponding to the four regions, the four code combined orientation patterns are respectively positioned in the four regions, and
Figure BDA00030190783000000837
at o position1In the vicinity of the location of the mobile station,
Figure BDA00030190783000000838
at o position2In the vicinity of the location of the mobile station,
Figure BDA00030190783000000839
at o position3In the vicinity of the position of the mobile phone,
Figure BDA00030190783000000840
at o position4And the ordering of the four code combinations is determined accordingly. In a preferred embodiment of the method of the invention,
Figure BDA00030190783000000841
and o1The two layers are overlapped with each other,
Figure BDA00030190783000000842
and o2The overlapping is carried out on the two sides of the steel pipe,
Figure BDA00030190783000000843
and o3The two layers are overlapped with each other,
Figure BDA00030190783000000844
and o4Overlap as shown in fig. 2.
In this embodiment, if N is 757, the code number is 757Coded composite orientation pattern of coded signs
Figure BDA00030190783000000845
The distribution of (c) is shown in fig. 3.
S60: each region
Figure BDA0003019078300000091
The coding sequence number of the coding combination pattern in the corresponding area is marked as Y, and the coding combination orientation pattern in the corresponding area is marked as
Figure BDA0003019078300000092
The geometric center of which is
Figure BDA0003019078300000093
In the Y-th code combination, the code combination code patterns in the corresponding areas are sequentially marked as
Figure BDA0003019078300000094
Corresponding geometric centers are in turn
Figure BDA0003019078300000095
As shown in FIG. 2, from
Figure BDA0003019078300000096
Respectively leading to
Figure BDA0003019078300000097
Three directed line segments are obtained and are respectively marked as vectors
Figure BDA0003019078300000098
Vector
Figure BDA0003019078300000099
Vector
Figure BDA00030190783000000910
Simultaneous vector
Figure BDA00030190783000000911
Vector
Figure BDA00030190783000000912
Vector
Figure BDA00030190783000000913
Respectively with the standard vector alphaNAre respectively recorded as
Figure BDA00030190783000000914
As shown in the above formula (1). The positions of the 3 code combination code patterns within each code combination need to satisfy the following requirements: vector
Figure BDA00030190783000000915
There is a significant difference in die length or direction.
In the coding coordinate system oN-XNYNZNIn, memory vector
Figure BDA00030190783000000916
Vector
Figure BDA00030190783000000917
Vector
Figure BDA00030190783000000918
Respectively are
Figure BDA00030190783000000919
Setting:
Figure BDA00030190783000000920
the following conditions are satisfied:
Figure BDA00030190783000000921
whereby vectors can be distinguished
Figure BDA00030190783000000922
Vector
Figure BDA00030190783000000923
Vector
Figure BDA00030190783000000924
Thereby determining the code pattern of three code combinations in the Y code combination of the quadrilateral code mark with the number of N
Figure BDA00030190783000000925
The ordering of (c).
In this embodiment, if N is 757, the sequence of each code combination pattern of the code flag corresponding to the code number 757 and the sequence of the code combination code pattern in each code combination pattern are as shown in fig. 3.
S70: the Y-th code is combined with the K-th code combined code pattern in the quadrilateral code mark with the code number of N
Figure BDA00030190783000000926
The corresponding code value is recorded as
Figure BDA00030190783000000927
Wherein Y is 1,2,3,4, K is 1,2,3, and
Figure BDA00030190783000000928
is 0 or 1;
s80: for the quadrilateral coding mark with the coding number of N, the 12-bit binary number with the coding number of N is wNAnd specify
Figure BDA00030190783000000929
Sequentially and respectively corresponding to binary numbers w from the lowest order to the highest orderNAnd must satisfy the following formula:
GN·FN＝N (3)
wherein: column vector GN＝(20,21,22,23,24,25,26,27,28,29,210,211)T，
Column vector
Figure BDA0003019078300000101
In this embodiment, if N is 757, the column vector in the code flag corresponding to the code number 757 is F757＝(1,0,1,0,1,1,1,1,0,1,0,0)T。
S90: according to the Kth encoding combination encoding pattern of the Yth encoding combination in the quadrilateral encoding sign with the encoding number N determined in the step S80
Figure BDA0003019078300000102
Corresponding code value
Figure BDA0003019078300000103
To determine the corresponding code pattern
Figure BDA0003019078300000104
Including the following two states:
a first state: if the coding is combined with the coding pattern
Figure BDA0003019078300000105
Corresponding code value
Figure BDA0003019078300000106
The code combines the code pattern
Figure BDA0003019078300000107
Is color 1. Wherein, Y is 1,2,3,4, K is 1,2, 3;
and a second state: if the code is combined with the coding pattern
Figure BDA0003019078300000108
Corresponding code value
Figure BDA0003019078300000109
The code combines the code pattern
Figure BDA00030190783000001010
Is color 2. Wherein, Y is 1,2,3,4, K is 1,2, 3.
In this embodiment, the column vector in the code flag corresponding to the code number 757 is F757＝(1,0,1,0,1,1,1,1,0,1,0,0)TI.e. by
Figure BDA00030190783000001011
Is 0, then the corresponding code combination code pattern
Figure BDA00030190783000001012
Figure BDA00030190783000001013
Is color 1, i.e., black; the rest(s)
Figure BDA00030190783000001014
Is 1, then the corresponding code is combined with the code pattern
Figure BDA00030190783000001015
Is color 2, i.e. white. Therefore, each code combination code pattern in the quadrilateral code mark with the code number of 757 corresponds
Figure BDA00030190783000001016
The color state of (2) is shown in fig. 4.
Therefore, the encoding work of the quadrilateral encoding mark is completed, and the encoding serial number of each angular point can judge the position of the uniquely determined angular point on the quadrilateral encoding mark. In the process of three-dimensional measurement of the visual structured light, four corner points of the quadrilateral coding mark are used for three-dimensional point cloud splicing of a target curved surface, so that the characteristics of extraction and high-precision positioning can be realized, and the positioning of the high-precision quadrilateral coding mark, the high-precision three-dimensional point cloud splicing and the like can be realized.
The encoding method based on quadrilateral encoding signs provided by the invention needs to compile a corresponding computer program and execute the program on a computer to realize corresponding operation processing and logic control functions, so the invention also provides a computer readable storage medium comprising the computer program used in combination with an electronic device with an image processing function, and the computer program can be executed by a processor to execute the encoding method.
The above description is only an embodiment of the present invention, and is not intended to limit the scope of the present invention, and all equivalent structures or equivalent processes performed by the present invention or directly or indirectly applied to other related technical fields are included in the scope of the present invention.

Claims (9)

1. A coding method of a parallelogram coding mark based on a graph geometric relationship is characterized in that: the mark is a square coding square, a quadrilateral background pattern and a coding pattern are arranged on the surface of the coding square, and the coding pattern is positioned inside the quadrilateral background pattern;
the coding pattern comprises a positioning pattern, an orientation pattern and a coding combination pattern, the orientation pattern and the positioning pattern are used for judging the direction of the quadrilateral coding mark, and the coding combination pattern is used for coding each corner point of the quadrilateral coding mark
The encoding method comprises the following steps:
s10: marking the coding number of the quadrilateral coding mark as N, wherein N is a positive integer and belongs to [0,4095], and establishing a coding coordinate system of the quadrilateral coding mark with the coding number of N;
s20: selecting one vertex as the first vertex in the coding coordinate system
Figure FDA0003694787580000011
With the first vertex
Figure FDA0003694787580000012
Taking the direction of the quadrilateral coding mark as a starting point and looking forward by people, and coding the quadrilateral coding mark along the clockwise directionThe other three vertexes of the log are sequentially marked as second vertexes
Figure FDA0003694787580000013
Third vertex
Figure FDA0003694787580000014
And a fourth vertex
Figure FDA0003694787580000015
S30: the first vertex
Figure FDA0003694787580000016
The first vertex
Figure FDA0003694787580000017
Second vertex
Figure FDA0003694787580000018
Third vertex
Figure FDA0003694787580000019
And a fourth vertex
Figure FDA00036947875800000110
Sequentially used as the first corner point of the quadrilateral coding mark with the number N corresponding to
Figure FDA00036947875800000111
Second corner point
Figure FDA00036947875800000112
Third corner
Figure FDA00036947875800000113
The fourth corner point
Figure FDA00036947875800000114
S40: divide the quadrilateral grid into four regions
Figure FDA00036947875800000115
S50: in the quadrilateral coding mark with the serial number N, the four coding combination orientation patterns are respectively positioned in the four regions, and the geometric center of each coding combination orientation pattern is adjacent to or coincided with the geometric center of the region where the pattern is positioned, so that the sequence of the four coding combinations is determined;
s60: in each area
Figure FDA00036947875800000116
In which the orientation pattern is combined by the codes in the corresponding regions
Figure FDA00036947875800000117
Has a geometric center of
Figure FDA00036947875800000118
Starting from three coded combined coded patterns respectively
Figure FDA00036947875800000119
The geometric center of (A) is sequentially
Figure FDA00036947875800000120
Figure FDA00036947875800000121
Constructing vectors
Figure FDA00036947875800000122
Vector
Figure FDA00036947875800000123
Vector
Figure FDA00036947875800000124
Wherein, the first and the second end of the pipe are connected with each other,Y＝1,2,3,4；
differentiating vectors
Figure FDA00036947875800000125
Vector
Figure FDA00036947875800000126
Vector
Figure FDA00036947875800000127
To determine the size and direction of the three code pattern combinations
Figure FDA00036947875800000128
Sorting of (2);
s70: combining the Y-th code with the K-th code to form a code pattern in the quadrilateral code mark with the code number N
Figure FDA00036947875800000129
The corresponding code value is noted as
Figure FDA00036947875800000130
Wherein Y is 1,2,3,4, K is 1,2,3, and
Figure FDA00036947875800000131
is 0 or 1;
s80: for the quadrilateral coding mark with the coding number of N, the 12-bit binary number with the coding number of N is wNAnd define
Figure FDA0003694787580000021
Sequentially and respectively corresponding to binary numbers w from the lowest order to the highest orderNAnd must satisfy the following formula:
GN·FN＝N
wherein: column vector GN＝(20,21,22,23,24,25,26,27,28,29,210,211)T；
Column vector
Figure FDA0003694787580000022
S90: according to the Kth encoding combination encoding pattern of the Yth encoding combination in the quadrilateral encoding mark with the encoding number determined in the step S80 and corresponding to the N
Figure FDA0003694787580000023
Corresponding code value
Figure FDA0003694787580000024
To determine the corresponding code pattern
Figure FDA0003694787580000025
The color of (c).
2. The method as claimed in claim 1, wherein the method comprises the following steps: the number of the coding combination patterns is four, and each coding combination pattern is composed of one coding combination orientation pattern and three coding combination coding patterns.
3. A method for encoding a parallelogram-shaped coded flag based on geometric relationships of figures as set forth in claim 2, wherein: the positioning pattern, the orientation pattern, each coding combination orientation pattern and each coding combination coding pattern are not overlapped and not communicated.
4. The method as claimed in claim 2, wherein the method comprises the following steps: the colors of the orientation pattern, the positioning pattern, the coding combination orientation pattern and the coding combination coding pattern are the same, and are obviously different from the color of the quadrilateral background pattern.
5. The method as claimed in claim 2, wherein the method comprises the following steps: the area of any one of the coding combination coding patterns is smaller than that of any one of the orientation patterns, and the area of any one of the coding combination orientation patterns is smaller than that of any one of the coding combination coding patterns.
6. The method as claimed in claim 1, wherein the method comprises the following steps: and a connecting line segment of the geometric center of the orientation pattern and the geometric center of the positioning pattern and one edge of the coding square, and the middle point of the connecting line segment is adjacent to/coincided with the geometric center point of the coding square.
7. The method as claimed in claim 2, wherein the coding method of the parallelogram coding flag based on the graph geometry relationship comprises: four corners of the quadrilateral background pattern are divided into four regions, each region is internally provided with a coding combination pattern, and the geometric center of each coding combination orientation pattern is adjacent to/coincided with the geometric center of the region where the coding combination orientation pattern is positioned.
8. The method according to claim 2 or 7, wherein the method comprises the following steps: within each code combination pattern, the positions of the three code combination code patterns satisfy the formula:
Figure FDA0003694787580000031
wherein the content of the first and second substances,
Figure FDA0003694787580000032
there is a significant difference in die length or direction;
n is the code number of the quadrilateral coding mark, N is a positive integer, and N belongs to [0,4095 ];
y is the code number of the code combination pattern in each region, and Y is 1,2,3, 4;
αNa standard vector resulting from directing the geometric center of the positioning pattern to the geometry of the orientation pattern;
Figure FDA0003694787580000033
the geometric centers of the orientation patterns are directed to the resulting vectors of the geometric centers of the three encoding combination encoding patterns, respectively, for the encoding combination.
9. A computer-readable storage medium comprising a computer program for use in conjunction with an electronic device having image processing capabilities, the computer program being executable by a processor to perform the encoding method of claim 1.
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