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Method and device for acquiring coordinates of point cloud by oblique photography

A technology of oblique photography and oblique shooting, which is applied in the field of surveying and mapping, can solve the problems of large error of point cloud data, inconsistency between point cloud position and actual position, etc., to improve accuracy, reduce uneven change of point cloud elevation, and overcome the problem of forced distribution Effect

Inactive Publication Date: 2017-08-18
CHINA ACADEMY OF ELECTRONICS & INFORMATION TECH OF CETC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The main purpose of the present invention is to propose a method and device for oblique photography to obtain point cloud coordinates, which solves the problems of large errors in the point cloud data obtained in the prior art and the inconsistency between the point cloud position and the actual position

Method used

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  • Method and device for acquiring coordinates of point cloud by oblique photography
  • Method and device for acquiring coordinates of point cloud by oblique photography
  • Method and device for acquiring coordinates of point cloud by oblique photography

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Embodiment 1

[0039] Specific as figure 1 As shown, this embodiment provides a method for oblique photography to obtain point cloud coordinates, including:

[0040]S1: Obtain the point cloud coordinates of the subject based on dense matching and forward intersection of multiple images taken at an angle;

[0041] S2: Determine a "flat" area according to the point cloud coordinates, and the height difference of the "flat" area is within a preset threshold range;

[0042] S3: Construct the triangulation network of the "flat" area, and obtain the data characteristics of the triangulation network;

[0043] S4: Establish an adjustment model according to the data characteristics of the triangulation and collinear equations, linearize the adjustment model, and obtain the three-dimensional coordinates of the point cloud.

[0044] The method for obtaining point cloud coordinates by oblique photography provided by the embodiment of the present invention first uses the overlapping images obtained by ...

Embodiment 2

[0048] Specific as figure 2 As shown, this embodiment 2 is optional on the basis of embodiment 1. The above-mentioned adjustment model is established based on the data characteristics of the triangulation network and the collinear equation, and the adjustment model is linearized to obtain the three-dimensional coordinates of the point cloud , including S14, specifically S14 is:

[0049] Constructing a smooth energy function according to the data characteristics of the triangulation;

[0050] An adjustment model is established according to the collinear equation;

[0051] Add the smoothing energy function as a constraint to the adjustment model, linearize the adjustment model, and obtain the three-dimensional coordinates of the point cloud, thereby, using the smoothing energy function as a constraint, construct an error equation and solve Realize the rigorous calculation of the three-dimensional space coordinates of the global optimal multi-slice space forward intersection, ...

Embodiment 3

[0055] combine Figure 4 As shown, this embodiment 3 makes the following optimizations for the above-mentioned embodiment 1 and embodiment 2. In this embodiment, multi-chip dense matching is first performed, and then the initial rigorous calculation, "flat" area detection and constraints are sequentially performed. Rigorous calculations under the conditions.

[0056] Among them, the initial rigorous solution includes the initial solution of beam method forward intersection (least squares solution); "flat" area detection includes "flat" area detection and the construction of triangulation; the rigorous calculation under constraint conditions includes grid fairing energy Function construction, error equation construction and rigorous value solution.

[0057] In the method for obtaining point cloud coordinates by oblique photography provided by the embodiment of the present invention, the calculation process of point cloud coordinates is: multi-slice dense matching--beam method ...

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Abstract

The invention provides a method and a device for acquiring coordinates of a point cloud by oblique photography, so as to solve the problem of inconsistency existing between the point cloud position and the actual position in oblique photography measurement. The method comprises steps: through carrying out dense matching and forward intersection on multiple images obtained through oblique photography, point cloud coordinates of a photographed object are acquired; according to the point cloud coordinates, flat areas are determined, wherein the altitude difference among the flat areas is located in a preset threshold interval; a triangulation network for the flat areas is built, and data features of the triangulation network are acquired; and according to a collinearity equation and a smoothing energy function, an adjustment model is built, the adjustment model is linearized, and three-dimensional coordinates of the point cloud are acquired. The method uses the flat areas as constraint conditions for point cloud calculation, error match phenomena of the point cloud caused by altitude difference changes can be reduced, and the point cloud position and the actual position are thus consistent.

Description

technical field [0001] The invention relates to the field of surveying and mapping, in particular to a method and device for acquiring point cloud coordinates by oblique photography. Background technique [0002] At present, oblique aerial photogrammetry has been more and more widely used in the country, and one of the key issues of oblique aerial photogrammetry is to calculate point clouds through dense matching. [0003] However, due to the influence of dense matching accuracy, mis-matching, image geometric distortion, outer orientation element calculation error and intersection angle in the measurement system, the distribution of various errors using the traditional least squares calculation model can easily lead to the difference between point cloud position and There are inconsistencies between actual locations. This inconsistency is particularly prominent when the height difference changes. The prominent performance is that the point cloud has a large height differenc...

Claims

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Application Information

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IPC IPC(8): G06T7/00
CPCG06T2207/10028
Inventor 岳贵杰魏曦谢海永
Owner CHINA ACADEMY OF ELECTRONICS & INFORMATION TECH OF CETC
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