A geographical point matching method based on frequency constraint and triangle principle

Abstract

The present invention discloses a geographical point matching method based on frequency constraint and triangle principle, belonging to the field of geographical information processing. It includes: obtaining a set of geographical points to be matched and a set of basic geographical points; calculating the topological structure; calculating the topological structure with distance constraint; finding the most similar candidate triangle descriptors of each triangle descriptor in the topological structure of the set of geographical points to be matched in the topological structure of the set of basic geographical points; obtaining all sets of basic geographical points, and counting the frequency of occurrence of each geographical point; screening out the sets of basic geographical points greater than the frequency threshold; forming a new descriptor set; counting all the basic geographical points included in the descriptor set to obtain the point set successfully matched with the set of geographical points to be matched. The present invention makes full use of the spatial position distribution relationship of geographical points, combines the topological structure characteristics of the set of points to be matched, and adopts multi-attribute constraints to improve the reliability of matching, and is applicable to matching local geographical points from a large number of geographical points.

Description

Technical Field

[0001] The present invention belongs to the field of geographic information processing, and particularly relates to a geographic point matching method based on frequency constraint and triangle principle. Background Art

[0002] With the rapid development of geographic information and surveying and mapping technologies, the acquisition and obtaining of various geographic information data have become convenient and are gradually applied to many fields such as land resource planning, engineering construction, and navigation. To better serve various fields, the overall management of geographic information data has become the primary key issue. However, there are many inconsistencies in various data in terms of scale, version, geometric position, and data format, which increases the threshold for the comprehensive application of geographic information data.

[0003] The diversification of geographic space data acquisition methods has led to the emergence of a large amount of spatial data. Points with geographic coordinates, as an important type of vector data, have extensive applications in coordinate system conversion, image geometric correction, point cloud data positioning, Internet maps, etc. Due to the differences in geographic point data in terms of scale, acquisition time, data format, service purpose, and accuracy, there are systematic deviations when they are applied in multi-source data fusion, which brings difficulties to the comprehensive and convenient application of spatial data. Therefore, the efficient and accurate matching between point sets with the same geographic entity meaning and geographic location is particularly important, which can provide basic technical support for the fusion application of data. However, there is no existing technology research on how to use the spatial relationship between geographic points to achieve the efficient and accurate matching of geographic point data. Summary of the Invention

[0004] In view of this, the present invention provides a geographic point matching method based on frequency constraint and triangle principle, which can make full use of the spatial position distribution relationship of geographic points, and combine the topological structure characteristics of the point set to be matched, and adopt multi-attribute constraints to improve the reliability of matching. The method is applicable to matching local geographic points from a large number of geographic points.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A geographic point matching method based on frequency constraint and triangle principle, comprising the following steps:

[0007] Step 1, respectively obtain the set S of geographic points to be matched m and the set S of basic geographic points b ;

[0008] Step 2, calculate its topological structure T according to the set S of geographic points to be matched m ; Sm ;

[0009] Step 3, according to the set S of geographic points to be matched mDetermine the distance constraint R based on the two points with the farthest distance, and calculate the set S of basic geographical points b Topological structure with distance constraint

[0010] Step 4: Search for each triangle descriptor in the topological structure respectively in the topological structure the set H of the most similar candidate triangle descriptors i ;

[0011] Step 5: Obtain the set of all candidate triangle descriptors ∪H i and the set of basic geographical points it contains and count the frequency F of each geographical point appearance;

[0012] Step 6: According to the frequency F of the set of basic geographical points and the set S of geographical points to be matched m , screen out the set of basic geographical points greater than the frequency threshold

[0013] Step 7: Traverse each triangle descriptor in all candidate triangle descriptor sets ∪H i and judge whether the geographical points it contains are included in the set of basic geographical points if included, retain the descriptor, and finally form a new set H' of triangle descriptors;

[0014] Step 8: Count all the basic geographical points included in the set H' of triangle descriptors, and obtain the set of geographical points which is the point set successfully matched with S m is the successfully matched point set.

[0015] Furthermore, the topological structure in Step 2 is expressed as:

[0016]

[0017] where N m is the number of geographical points to be matched in the set S m , is the i-th triangle descriptor, expressed as:

[0018]

[0019] In the formula, and are any three non-repeating geographical points in the set S m , and ​respectively represent the minimum and maximum interior angles of the triangle formed by three points that constitute the topological structure descriptor The minimum and maximum interior angles of the triangle formed by three points that constitute .

[0020] Furthermore, the topological structure with distance constraints in step 3 is expressed as:

[0021]

[0022] where N b is the number of geographical points in the set S b and is the i-th triangle descriptor, expressed as: In the formula,

[0023]

[0024] In the formula, and are any three non-repeating geographical points in the set S b , and respectively represent the minimum and maximum interior angles of the triangle formed by the three points that constitute , and dis max (*,*,*) is to find the maximum distance between any two of the three points.

[0025] Furthermore, the triangle descriptor in step 4 is the set H of the most similar candidate triangle descriptors in the topological structure i expressed as:

[0026] Satisfying

[0027]

[0028] where o n represents the number of the triangle descriptor in the topological structure , n is the number of triangle descriptors in the set H i , and represents the angular space distance between the triangle descriptors and , and its expression is:

[0029]

[0030] In the formula, and respectively represent 's minimum and maximum interior angles, and respectively represent 's minimum and maximum interior angles.

[0031] Further, the set of basic geographic points screened in step 6 is expressed as:

[0032]

[0033] wherein, represents the t-th geographic point in the set of geographic points j , is the coordinate of this geographic point, is the frequency of occurrence of this geographic point, c2 is the number of geographic points included in the set of geographic points , and N m is the number of geographic points to be matched in the set S m .

[0034] Further, the new descriptor set H' in step 7 is expressed as:

[0035]

[0036] wherein, represents the v-th j descriptor in the set H', is any one of the three points of the descriptor .

[0037] The present invention has the following beneficial effects:

[0038] 1. The present invention proposes a geographic point matching method based on frequency constraint and triangle principle, which can effectively realize the rapid matching of point sets and provide theoretical support for the regional search and matching of geographic points.

[0039] 2. The method of the present invention has strong robustness and is still effective when the point set to be matched is translated, rotated as a whole, and scaled relative to the true position, and can be applied to aspects such as road intersection point, geographic control point, and geographic sampling point matching. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic diagram of the principle of the geographic point matching method based on frequency constraint and triangle principle. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] The following further describes the present invention in detail with reference to the drawings and specific embodiments.

[0042] A geographic point matching method based on frequency constraint and triangle principle, as Figure 1 shown, includes the following steps:

[0043] Step 1, obtain the set S of geographic points to be matchedm When the set S m contains N m points, it can be expressed as:

[0044]

[0045] Obtain the basic geographical point set S b When the set S b contains N b points, it can be expressed as:

[0046]

[0047] In the formula, x and y respectively represent the coordinates of the geographical point, and Id represents the number of the geographical point.

[0048] Step 2, calculate its topological structure T according to the geographical point set S to be matched m The calculation method is as follows: Sm

[0049]

[0050] Among them, N m is the number of geographical points to be matched in the set S m , is the i-th triangle descriptor and can be expressed as:

[0051]

[0052] In the formula, a1, a2, and a3 are respectively the serial numbers of any non-repeating geographical points in the set S m , and respectively represent the minimum interior angle and the maximum interior angle of the triangle formed by the three points constituting the topological structure descriptor .

[0053] Step 3, determine the distance constraint R according to the two points with the farthest distance in the geographical point set S to be matched, and calculate the topological structure with distance constraint of the basic geographical point set S m The calculation method is as follows: b

[0054]

[0055] Among them, N b is the number of geographical points in the set S b , is the i-th triangle descriptor and can be expressed as:

[0056] ​​​

[0057] In the formula, e1, e2, and e3 are respectively the b serial numbers of any non-repeating geographical points in the set S, and respectively represent the minimum interior angle and the maximum interior angle of the triangle formed by the three points that make up , and dis max (*,*,*) is to find the maximum distance between any two of the three points.

[0058] Step 4: Search for each triangle descriptor in the topological structure in the most similar candidate triangle descriptor set H in the topological structure i , and its calculation method is as follows:

[0059] Satisfy

[0060]

[0061] where o n represents the serial number of the triangle descriptor in the topological structure , n is the number of triangle descriptors in the set H i , represents the angular spatial distance between the triangle descriptors and , and its expression is:

[0062]

[0063] In the formula, and respectively represent 's minimum interior angle and maximum interior angle, and respectively represent 's minimum interior angle and maximum interior angle.

[0064] Step 5: Obtain all candidate descriptor sets H, which can be expressed as:

[0065]

[0066] In the formula, q i represents the geographical point descriptor serial number.

[0067] Then the set of basic geographical points included in the set H can be expressed as:

[0068]

[0069] where l jRepresents the number of a geographical point, and c1 is a set of geographical points contains the number of geographical points.

[0070] From the set of geographical points it is possible to count the frequency of occurrence F of each point, and the calculation method is as follows:

[0071]

[0072] In the formula, represents the frequency of occurrence of the geographical point numbered .

[0073] Step 6, based on the set of basic geographical points with frequency F and the set S of geographical points to be matched m , filter out the set of basic geographical points greater than the frequency threshold which is expressed as follows:

[0074]

[0075] where t j represents the number of the set of geographical points , c2 is the set of geographical points contains the number of geographical points, and N m is the set S m contains the number of geographical points to be matched.

[0076] Step 7, traverse each triangular descriptor in the candidate descriptor set H Judge whether the geographical points it contains are included in the set of basic geographical points . If so, retain the descriptor. Finally, form a new descriptor set H', which is expressed as follows:

[0077]

[0078] where v j represents the number of the descriptor in the set H', is a descriptor the number of any one of the three points.

[0079] Step 8, count all the basic geographical points included in the descriptor set H', and the obtained geographical point set is the point set successfully matched with S m . Finally, the geographical point set can be expressed as:

[0080]

[0081] In the formula, c3 is the set The number of all geographical points.

[0082] In summary, the geographical point matching method based on frequency constraint and triangle principle proposed by the present invention aims at the problem of difficult matching of multiple geographical points, proposes a descriptor method for describing the topological structure of geographical points, selects a candidate matching point set through preliminary screening, and further refines the screening according to the frequency and triangle principle, providing key technical support for applications such as fusion, registration, and update of various forms of geographical points.

Claims

1. A geographic point matching method based on frequency constraint and triangle principle, characterized in that Including the following steps: Step 1, obtain the set S of geographical points to be matched respectively m and the set S of basic geographical points b ; Step 2, according to the set S of geographical points to be matched m calculate its topological structure Step 3, according to the set S of geographical points to be matched m Determine the distance constraint R based on the two points with the farthest distance in it, and calculate the basic set S of geographical points b Topological structure with distance constraint Step 4, search for the topological structures respectively for each triangle descriptor in the topological structure for the most similar set H of candidate triangle descriptors i ; Step 5, obtain all candidate triangle descriptor sets ∪H i The set of basic geographical points included And count the frequency F of occurrence of each geographical point; Step 6, according to the frequency F of the basic geographic point set and the set S of geographic points to be matched m , filter out the basic geographic point set with a frequency greater than the frequency threshold Step 7, traverse each triangle descriptor in all candidate triangle descriptor sets ∪H i and judge whether the geographical points included in are included in the basic geographical point set . If included, retain the descriptor, and finally form a new triangle descriptor set H'.​​ Step 8, count all the basic geographical points included in the triangle descriptor set H', and the obtained geographical point set is the point set that m successfully matches with S 2. The geographic point matching method based on frequency constraint and triangle principle according to claim 1, characterized in that, The topological structure in Step 2 is expressed as: Among them, N m is the number of geographical points to be matched in the set S m , and is the i-th triangle descriptor, expressed as: In the formula, and are any three non-repeating geographical points in the set S m , and respectively represent the minimum interior angle and the maximum interior angle of the triangle formed by the three points that make up the topological structure descriptor .

3. A geographic point matching method based on frequency constraint and triangle principle according to claim 2, characterized in that, The topological structure with distance constraints in Step 3 It is expressed as: Among them, N b is the number of geographical points in the set S b , and is the i-th triangle descriptor, expressed as: Wherein, and are any three non-repeating geographical points in the set S b , and respectively represent the minimum interior angle and the maximum interior angle of the triangle formed by the three points that make up , and dis max (*,*,*) is to find the maximum distance between any two of the three points.​ 4. A geographical point matching method based on frequency constraint and triangle principle according to claim 3, characterized in that, The triangle descriptor in step 4 In the topological structure The set H of the most similar candidate triangle descriptors i Is expressed as: Meet where o n represents the number of the triangle descriptor in the topological structure , n is the number of triangle descriptors in the set H i , represents the angular spatial distance between the triangle descriptor and , and its expression is: Wherein, and respectively represent the minimum interior angle and the maximum interior angle of, and respectively represent the minimum interior angle and the maximum interior angle of.

5. A geographic point matching method based on frequency constraint and triangle principle according to claim 4, characterized in that The set of basic geographic points screened in step 6 It is expressed as: Among them, represents the t-th geographical point in the set of geographical points j , is the coordinate of this geographical point, is the frequency of occurrence of this geographical point, c2 is the number of geographical points included in the set of geographical points , N m is the set S m is the number of geographical points to be matched in the set.

6. The geographical point matching method based on frequency constraint and triangle principle according to claim 5, characterized in that The new descriptor set H' in step 7 is expressed as: Among them, represents the v-th j descriptor in the set H', is any one of the three points of the descriptor ​

Images