阅读说明：本技术 一种地基三维激光扫描的林分调查样木精准编码生成方法 (Method for generating accurate codes of forest stand survey sample trees through three-dimensional laser scanning of foundation ) 是由 温小荣 杨杰 刘磊 朱硕 于 2021-01-06 设计创作，主要内容包括：本发明公开了一种地基三维激光扫描的林分调查样木精准编码生成方法,属于林分调查领域。本发明针对目前地基三维激光扫描进行林分标准地调查时,扫描得到的激光点云数据其样木编号难以确定的问题；在进行实测样木测树因子对比时,传统的数字标号方法不能适应地基三维激光扫描进行林分标准地调查的样木标号需求的问题,提出一种地基三维激光扫描的林分调查样木精准编码生成方法,该方法通过将放了反光片的m×n宫格视为被染色的m×n宫格；设染色的格子数为k；求取宫格染色的解集S以及能被正确识别的情况解集S中元素个数|S|和耗材数N；能够快速确定单期或多期林分标准地每株样木的位置,以适应于地基激光进行林分调查的林木测树因子对比分析的需求。(The invention discloses a method for generating accurate codes of forest stand survey sample trees by three-dimensional laser scanning of a foundation, and belongs to the field of forest stand survey. The method aims at the problem that the sample wood number of the laser point cloud data obtained by scanning is difficult to determine when forest stand standard ground investigation is carried out by foundation three-dimensional laser scanning at present; when actual measurement sample tree measurement factor comparison is carried out, the traditional digital labeling method cannot adapt to the problem of sample tree labeling requirements of forest standard ground investigation carried out by foundation three-dimensional laser scanning, and a forest stand investigation sample tree accurate coding generation method of foundation three-dimensional laser scanning is provided, wherein m × n grids with light reflecting sheets are regarded as dyed m × n grids; setting the number of dyed grids as k; solving a solution set S of the grid dyeing, and the number | S | and the number N of consumables in the condition solution set S which can be correctly identified; the position of each sample tree in a single-stage or multi-stage forest stand standard area can be quickly determined so as to meet the requirements of forest tree measuring factor comparative analysis of forest stand investigation by using laser on the basis.)

1. A method for generating accurate codes of forest stand survey sample trees by ground-based three-dimensional laser scanning is characterized by comprising the following steps:

1) the mxn grid with the reflecting sheet is regarded as a dyed mxn grid; setting the number of dyed grids as k;

2) when the first dyed lattice is in the first row and the first column, the cases of dyeing k-1 in the remaining mn-1 lattices are solutions, and the solutions are totallyA plurality of;

3) when the first grid is in other columns t of the first row, filling k-2 grids to be dyed into grids before the last column of the last row after the first dyed grid according to a certain sequence, namely, k-2 grids need to be dyed in mn-t-1 grids;

4) if the last but one dyed lattice is in the first row or the last but one dyed lattice is not in the first row but there is a dyed lattice in the first row, all the spaces behind it can form an independent solution; if the penultimate dyed lattice is in the non-first column of the penultimate row, the solution is 0; if the penultimate lattice is in a non-first row and a non-penultimate first row, subtracting the number of rows of the lattice from the total number of rows of the grid to obtain the number of independent solutions;

5) accumulating the number of the solutions to obtain a solution set S of the grid dyeing;

6) the condition that the total energy in the mxn grids can be correctly identified is the number | S | of elements in the solution set S, the number of consumables, namely the number of reflectors, is the sum of the dyeing numbers in the solution set S, and N is used for representing the number of consumables.

2. The method for generating the accurate codes of the forest stand survey sample trees based on the three-dimensional laser scanning of the foundation according to claim 1, wherein k is more than or equal to 1 and less than or equal to mn in the step 1).

3. The method for generating the accurate codes of the forest stand survey sample trees based on the three-dimensional laser scanning of the foundation according to claim 1, wherein t is more than 1 and less than or equal to n in the step 3).

4. The method for generating accurate codes of forest stand survey sample trees based on three-dimensional laser scanning as claimed in claim 1, wherein the effective occupancy rate is

5. The method as claimed in claim 1, wherein when the mxn grid is a 3 x 3-dimensional nine-grid, the number of elements | S | in solution set S is 400 if a total number of the 3 x 3-dimensional grid can be correctly identified.

6. The method for generating the accurate code of the forest stand survey sample tree based on the three-dimensional laser scanning as claimed in claim 1, wherein the number of consumables N is 1952 when the m x N grid is a 3 x 3 dimension nine grid.

7. The method for generating the accurate codes of the forest stand survey sample trees based on the three-dimensional laser scanning of the foundation as claimed in claim 1, wherein when the m x n grid is a 3 x 3 dimensional nine grid, the effective occupancy rate is 0.542222.

Technical Field

The invention belongs to the field of forest stand investigation, and particularly relates to a method for generating accurate codes of forest stand investigation sample trees by ground-based three-dimensional laser scanning.

Background

When forest stand standard land investigation is carried out by foundation three-dimensional laser scanning, forest stand standard land sample trees need to be marked, and the traditional digital marking method cannot meet the requirements of the forest stand standard land investigation sample tree marking by foundation three-dimensional laser scanning because the corresponding serial numbers of the trees in the spliced data of a plurality of stations cannot be distinguished. In addition, the existing technology for extracting the foundation three-dimensional laser scanning data cannot visually find some trees meeting the special requirements of researchers (such as felling, withering, disease attack or competition) in comparison with a plurality of stages of standards, and cannot rapidly position the positions of the trees in the standard ground. In order to solve the problems, a specific coding method capable of identifying three-dimensional laser scanning data of the foundation is adopted, a specific coded label is made for each sample tree in the forest stand standard, and the number can be displayed and rapidly identified after the three-dimensional laser scanning of the foundation.

In the manufacture of such specific tags, materials capable of reflecting lidar, referred to as reflectors, are selected. The reflecting sheets on the market are all square, and if the area of a region to be measured is large and the number of objects to be measured is large, how to save material cost is also an urgent problem to be solved.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a method for generating accurate codes of forest stand survey sample trees by ground-based three-dimensional laser scanning.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a method for generating accurate codes of forest stand survey sample trees by ground-based three-dimensional laser scanning comprises the following steps:

1) the mxn grid with the reflecting sheet is regarded as a dyed mxn grid; let the number of dyed lattices be k:

2) when the first dyed lattice is in the first row and the first column, the cases of dyeing k-1 in the remaining mn-1 lattices are solutions, and the solutions are totallyA plurality of;

3) when the first grid is in other columns t of the first row, filling k-2 grids to be dyed into grids before the last column of the last row after the first dyed grid according to a certain sequence, namely, k-2 grids need to be dyed in mn-t-1 grids;

4) if the last but one dyed lattice is in the first row or the last but one dyed lattice is not in the first row but there is a dyed lattice in the first row, all the spaces behind it can form an independent solution; if the penultimate dyed lattice is in the non-first column of the penultimate row, the solution is 0; if the penultimate lattice is in a non-first row and a non-penultimate first row, subtracting the number of rows of the lattice from the total number of rows of the grid to obtain the number of independent solutions;

5) accumulating the number of the solutions to obtain a solution set S of the grid dyeing;

6) the condition that the total energy in the mxn grids can be correctly identified is the number | S | of elements in the solution set S, the number of consumables, namely the number of reflectors, is the sum of the dyeing numbers in the solution set S, and N is used for representing the number of consumables.

Further, in the step 1), k is more than or equal to 1 and less than or equal to mn.

Further, in the step 3), t is more than 1 and less than or equal to n.

Further, effective occupancy rate

Further, when the m × n grid is a 3 × 3-dimensional nine grid, a case where a total of the 3 × 3-dimensional grids can be correctly recognized is that the number | S | of elements in the solution set S is 400.

Further, when the m × N grid is a 3 × 3 dimension nine grid, the number of consumables N is 1952.

Further, when the m × n grid is a 3 × 3 dimensional grid, the effective occupancy rate is 0.542222.

Has the advantages that: compared with the prior art, the invention has the advantages that:

the method aims at the problem that the sample wood number of the laser point cloud data obtained by scanning is difficult to determine when forest stand standard ground investigation is carried out by the existing foundation laser; when actual measurement sample tree measurement factor comparison is carried out, the traditional digital labeling method cannot adapt to the problem of sample tree labeling requirements of forest stand standard land survey carried out by foundation three-dimensional laser scanning, and discloses a forest stand survey sample tree accurate coding generation method based on foundation three-dimensional laser scanning, which can quickly determine the position of each sample tree in single-stage or multi-stage forest stand standard land so as to adapt to the requirements of forest tree measurement factor dynamic monitoring comparison analysis of forest stand survey carried out by foundation laser.

Drawings

FIG. 1 is a schematic diagram of forest stand standard survey sample wood numbering;

FIG. 2 is an effect diagram of a foundation three-dimensional laser scanning sample wood with a number diagram;

FIG. 3 is a plot of the number of staining events for the Sudoku staining problem;

fig. 4 to fig. 10 are nine-grid encoding result diagrams generated by the encoding method of the present invention.

Detailed Description

The invention is further described with reference to specific examples. These examples are intended to illustrate the invention and are not intended to limit the scope of the invention.

Example 1

In the point cloud data, only the reflective patch on the reflection image can be clearly interpreted, and the 3 × 3 dimensional squared figure behind it is not visible. Thus, the data obtained by scanning two codes with the ground-based three-dimensional laser with similar geometrical characteristics can be the same. As shown in fig. 1-2, fig. 2 is the actual scanning effect diagram of fig. 1, and the numbering of fig. 1(e) has 4 cases in a 3 × 3 dimensional grid of nine squares, wherein fig. 1(a) and 1(b) are 2 cases, and the other two cases are respectively the fig. 1(c) in which the stained area in fig. 1(a) is simultaneously shifted downward by one grid and the fig. 1(d) in which the stained area in fig. 1(b) is simultaneously shifted upward by one grid. When the number of objects to be detected is large, the number of situations that the reflectors placed in the 3 x 3 dimensional nine-square grid can be correctly identified at most needs to be calculated. The 3 x 3 dimensional nine-square grid with the reflector is assumed to be a dyed nine-square grid.

Nine design of quilt dyeingThe grid is M, and the solution set S satisfiesAbsence of M_jE.g. S, i ≠ j, such that M_jM can be obtained by translating the dyed area_iIf the total energy is correctly identified, the total number of elements in the solution set S is | S |, and the number of consumables is the sum of the number of dyes in each nine-square in S, which is recorded as N.

The inscription is 1 stained and 0 unstained, as in the nine-palace grid in FIG. 1, (a) can be written as(b) Can be recorded asSimilarly, we can also find M₁Having "same propertiesSo these four cases can only retain one solution in the solution set S, and so on. It should be noted that translation can only be done within the boundaries of the squared figure, and cyclic translation cannot occur, such asAndlet the grid in the ith row and the jth column in the nine-square grid be a_ijThen M is₅A of (a)₁₃Can not move to M₆A of (a)₁₁In position, therefore M₅And M₆Are two elements in the solution set.

For more generality, the Sudoku is expanded to m × n lattices, which can be represented by an m × n matrix, where m is the number of rows of the m × n lattices, n is the number of columns of the m × n lattices, and the number of stained lattices is k, obviously 1 ≦ k ≦ mn.

(1) It is only necessary to judge the case where the first dyed lattice is at the solution of the first row, because the first dyed lattice at other rows can be obtained by shifting down the elements of the solution set of the first dyed lattice at the first row.

(2) When the first dyed lattice is in the first row and the first column, the cases of dyeing k-1 in the remaining mn-1 lattices are solutions, and the solutions are totallyA plurality of;

(3) when the first grid is at the other columns t (1 < t ≦ n) of the first row, k-2 grids to be dyed are filled into the grids before the last column of the last row after the first dyed grid according to a certain sequence, namely, k-2 grids need to be dyed in mn-t-1 grids.

(4) If the last but one dyed lattice is in the first row or the last but one dyed lattice is not in the first row but there is a dyed lattice in the first row, all the spaces behind it can form an independent solution;

if the penultimate dyed lattice is in the non-first column of the penultimate row, the solution is 0;

if the penultimate lattice is in the non-first row and not the penultimate row, the total number of rows of the grid minus the number of rows of the lattice is the number of independent solutions.

(5) Accumulating the number of the solutions in the circulation to obtain a solution set S of the grid dyeing;

(6) the condition that the total energy in the mxn grids can be correctly identified is the number | S | of elements in the solution set S, the number of consumables, namely the number of reflectors, is the sum of the dyeing numbers in the solution set S, and N is used for representing the number of consumables.

The results of the nine-grid solution are shown in table 1. Let the number of dyeings x_i(here, x)_iK) corresponding to m × n lattice is set to the corresponding solution number n in solution set S_iTotal dyeing number N ═ Σ x_in_iAnd the effective occupancy rate is used for calculating the total dyeing number to account for the space when all the nine-square lattices in the solution set are not dyed (or after all the dyeing is removed) so as to evaluate the use efficiency of the reflector plate, namely the effective occupancy rate

TABLE 1 Sudoku staining problem solution results

xi	1	2	3	4	5	6	7	8	9
										ni	1	12	48	97	114	82	36	9	1

The number | S | of elements in the solution set S is 400, the total number N of dyes is 1952, and the effective occupancy rate is 0.542222.

The Sudoku coding results generated by the coding method are shown in fig. 4 to 10, and the Sudoku coding method can quickly determine the position of each sample tree in a single-stage or multi-stage forest stand standard area so as to meet the requirements of dynamic monitoring and comparative analysis of forest tree measuring factors for forest stand investigation by ground-based laser three-dimensional scanning.