Outer building wall crack detection system and method based on machine vision

Abstract

The invention relates to an outer building wall crack detection system and method based on machine vision. The system comprises a microcomputer processor, a CMOS sensor and a laser illumination system; the laser illumination system comprises four point-like laser transmitters arranged in the form of a rectangle; a transmission light beam is perpendicular to the imaging plane of a CMOS sensor; thecenter of the rectangular is positioned at the imaging center of the CMOS sensor; the microcomputer processor collects the image of the CMOS sensor in real time. According to the method, crack data isextracted via an image gray threshold processing and framework refining algorithm, the actual length corresponding to a unit pixel is acquired according to the pixel length of the rectangular formedby the extracted point-like laser, the absolute position of the current CMOS sensor under an outer wall reference system is acquired according to accumulation of relative movements between two frames,and thus the actual length of a crack and the coordinate of the crack under the outer wall reference system are acquired. According to the outer building wall crack detection system and method basedon machine vision provided by the invention, the automatic detection, size computation and coordinate positioning of the crack can be achieved, and the detection and positioning efficiencies of the crack are greatly improved.

Description

technical field [0001] The invention relates to the technical field of detection of building exterior walls, in particular to a system and method for detecting cracks in building exterior walls based on machine vision. Background technique [0002] With the development of my country's economic and social construction, there are more and more high-rise buildings, and the quality inspection of high-rise buildings has become increasingly important and difficult. As an important part of building quality inspection, the detection of cracks in the exterior walls of high-rise buildings is particularly difficult. On the one hand, high-rise buildings are high and difficult to climb, and manual climbing detection is inefficient and dangerous; on the other hand, cracks often appear irregular, and it is difficult to measure their characteristic data such as width and length. [0003] Machine vision is one of the hottest research topics in the field of automatic inspection. It obtains ...

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Problems solved by technology

[0005] Chinese patent application CN1081195933A discloses a building exterior wall quality defect detection system based on a kinect depth sensor. Through three-dimensional reconstruction of the wall surface, the size measurement and area calculation of defects such as wall cracks, depressions, hollows, etc. are realized, but The accuracy of the kinect depth sensor will be greatly reduced under strong sunlight, and the calculation of the size measurement method through 3D reconstruction is too large

[0006] Chinese patent application CN107202793A discloses a UAV-based building exterior wall quality defect detection system, which detects building exterior wall quality defects by collecting images with visible light and thermal imaging cameras mounted on the UAV, but it is not disclosed Specific image processing and detection methods, and the location of quality defects mainly depends on the GPS system, and the positioning error is large

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