Ancient city wall three-dimensional crack detection method based on dense point cloud

Abstract

The invention discloses an ancient city wall three-dimensional crack detection method based on dense point cloud, and the method comprises the following steps: S01, scanning an ancient city wall, andobtaining wall surface point cloud data; S02, adopting polynomial surface fitting to research area surface point cloud, and removing crack internal points; S03, performing dimension reduction analysison the point cloud after the internal points are removed by utilizing a principal component analysis method; s04, calculating the maximum included angle between two adjacent points; s05, judging crack boundary points, and obtaining a suspected crack boundary point sequence; s06, performing secondary identification and judgment according to the suspected crack boundary points obtained in S05 to obtain final crack boundary points; s07, according to the crack boundary points, extracting geometric parameters such as the main direction, the width and the length of the cracks; s08, converting the geometric parameters of the cracks into a three-dimensional coordinate system; s09, performing storage. The ancient city wall three-dimensional crack detection method based on the dense point cloud ishigh in automation degree and detection precision, three-dimensional geometrical parameters of all cracks of the wall are effectively extracted, and crossing from traditional two-dimensional crack detection to three-dimensional detection is achieved.

Description

technical field [0001] The invention specifically relates to a three-dimensional crack detection method of an ancient city wall based on a dense point cloud. Background technique [0002] As an important carrier of the combination of historical and cultural heritage and traditional features, the ancient city wall has high scientific, cultural and economic value. In order to better protect the ancient city wall, it is of great significance to detect three-dimensional cracks on it. The traditional mechanical measurement method generally needs to place measuring points on the city wall, and use vernier calipers to measure the width of cracks and other information. However, this type of method has obvious limitations: 1) The particularity of the city wall makes it not suitable for large-scale measurement on the wall. Placement of measuring points; 2) The detection of cracks is limited to two-dimensional forms, and the extraction of three-dimensional shapes cannot be realized; 3...

AI Technical Summary

Problems solved by technology

The traditional mechanical measurement method generally needs to place measuring points on the city wall, and use vernier calipers to measure the width of cracks and other information. However, this type of method has obvious limitations: 1) The particularity of the city wall makes it not suitable for large-scale measurement on the wall. Placement of measuring points; 2) The detection of cracks is limited to two-dimensional form, and the extraction of three-dimensional form cannot be realized; 3) It needs to be visually identified and marked; 4) The measurement distance is limited; 5) The work is cumbersome and labor-intensive

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