Building change detection method based on density of projection points of movable window

Abstract

The invention discloses a building change detection method based on the density of projection points of a movable window. The method comprises the steps that two periods of point cloud data are collected and registered; dimension-reducing analysis is carried out on a fixed wall; projection points of a station point in a plane of the fixed wall are calculated, and a structural coordinate system is established; the two periods of point cloud data are transformed to the structural coordinate system; a k-means classification method is used to obtain a brick point cloud and a mortar point cloud; the mortar point cloud is projected to the direction Z and the direction Y; a fixed window length Lfix and a movable window length Lmove are defined, and point-cloud linear density change along the direction Z and the direction Y is calculated; horizontal and vertical segmentation lines among bricks are calculated, coordinates of four corners of each brick and the center of each brick are calculated; and change is detected by utilizing the centers of the corresponding brick in two periods. According to the invention, deformation information of the centers of the bricks of the wall is extracted automatically, the automation degree is improved greatly, original data is mined fully, and it is ensured that deformation information of the bricks of a brick-structured building can be obtained effectively on the premise that the precision is ensured.

Description

Technical field [0001] The invention designs a building change detection method, in particular to a building change detection method based on a moving window. Background technique [0002] In cities, buildings are the main places for human activities, and their safety status is related to human daily life and economic activities. Therefore, the change detection of buildings is of great significance. Based on the change detection and repair of buildings, especially The deformation and damage of buildings caused by earthquakes has been the focus of research in the industry in recent years. In the history of the development of building structures, masonry structures have been widely used in building foundation structures since ancient times, using bricks, stones, and masonry. A combination of various blocks such as adobe and mortar (mortar, clay slurry, etc.) is a masonry structure. The masonry structure is widely used due to its low cost, fire resistance, durability and ease of con...

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Problems solved by technology

[0002] In cities, buildings are the main places for human activities, and their safety status is related to human daily life and economic activities. Therefore, it is of great significance to detect changes in buildings. Based on the change detection and repair of buildings, especially The deformation and damage of buildings caused by earthquakes has been the focus of research in the industry in recent years. In the development history of building structures, masonry structures have been widely used in the foundation structure of buildings since ancient times. Bricks, stones, masonry And adobe and other blocks, a combination of mortar (mortar, clay slurry, etc.) However, its masonry strength is low and its earthquake resistance is poor. Therefore, the research on change detection of masonry buildings has extremely important practical significance. The existing image-based change detection methods, according to the level of information processing , can be divided into pixel-based, feature-based, and target-based change detection, and the change detection of LiDAR (Light Detection And Ranging) LiDAR data has gradually begun to be studied in the field of photogrammetry and computer vision, and image-based change detection The accuracy of the method is not high enough, the target is not clear enough, and it is easily affected by the image quality. The obtained deformation information is not rich enough, and it is impossible to accurately obtain the deformation information of each brick in the masonry structure. In addition, the low degree of automation also seriously affects Efficiency of Change Detection

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