The Research Of The Remote Non-contact Detecting System Of Defects And Crack For The Civil Engineering Structure

In the construction and work process of building engineering, due to reason for design, construction, use and the others, the cracks often appear in the concrete structure, which affect its applicability and durability. And when the crack width expansion reaches a certain value, it may endanger the safety of the main structure. Despite a large number of achievements in scientific research and practice have proved that, concrete crack is difficult to avoid, which is a kind of material characteristic for concrete material, which can be accept by people, but the key to the problem is to control the degree of harmful in the permitted range.The development situation of the crack is one of the most important condition and pathological basis to diagnose, analyse and judge the morbidity of the existing buildings. According to its position and patterns, you can approximate inference the internal stress of concrete position, direction, its reason, harmfulness, and take corresponding measures. Therefore, judging the concrete health status, accurately grasping the concrete crack correctly, the patterns of the trend, width, length and depth, etc., which is important to put forward scientific and reasonable treatment scheme.At present, almost all the crack width detection is the traditional contact detection method, which is accuracy but low efficiency,dangerous, high economic cost and human cost.So it is in desperate need of a remote non-contact in current engineering detection practical application, which can reduce testing cost, improve work efficiency, and meet the requirements of intelligent measurement. Therefore, this research topic for building of intelligent detection, identification, evaluation work is of great significance.With the development of the digital optical photography technology, involves the optical camera hardware techniques such as optical lens, CCD, electronic components and other products performance index increased significantly, and cost gradually reduce, it is the technology condition to realize optical measurement.This topic is based on photometric method of digital image processing techniques, to measure and analyse the concrete surface crack width. Specific technical route:1. Shoot crack image using image acquisition system; 2. Image Preprocessing the collected image; 3. Detecting and sharpening the edge of the crack, making it more clearly discernible; 4. detecting and positioning the edge of crack, making sure that the differentiable profile edge of crack still keep clear in the amplification process, which is easy to pick up the edge position.This topic breaks the limitations in conventional method can only calculating horizontal and vertical direction of crack width, and puts forward a brand-new kind of calculation methods, which can calculate crack width in any trend and certain angle and pitching angle and the special circular arc in the plane, and then analyses the variety of error correction detailed. By experimental comparison, analysis and verification, this new method has higher precision after the error correction, can completely meet the detection needs for surface crack of building structure.In the finality, based on Java environment, using object oriented programming method, I write software in crack width detection, which realizes the direct measurement of crack width, makes the crack detection more visualizations, solves the traditional crack detection in low efficiency, the uncertainty and subjectivity, gives full play to the technology advantage in digital image processing. Using MySQL database, the software realize intelligent management the crack information.