Design Of A System For Building Surface Crack Measurement Based On Embedded

The existing building surface crack detection equipme nt has the disadvantage of low measure ment precision,ma nual reading style and inconvenient use,and the applicati on of embedded technology in the field of crack detection can improve the portability of equipment and improve the accuracy of measureme nt,which represents the development trend of crack detection field.Based on the e mbedded development Technology,mac hi ne vision technology a nd digital image processing technology,this thesis designs a set of detection system o f crack width,length,perimeter and area,which can achieve both near distance and long distance measurement..The main work done in this thesis is:(1)Hardware platform construction: With the OK210 development b oard to build the embedded processing syste m,the digital microscope to construct the near distance vision syste m,the electronic eyepiece and the optical telescope to construct the long distance vision system and the infrared laser rangefinder to co nstruct the distance measuring s yste m,co mpletes the long distance and the near distance measurement platform construction work.(2)Software system development: Developing crack detection softw are under the Cent OS 6.7 syste m platform,based on QT design graphical user interface,complete the development of function modules such as image acquisition,image processing,image calibration and crack eigenvalue measure ment.Ima ge Acquisition mod ule to achieve image acquisition,display,capture and save,image processing mod ule on the acquisition of gray,filtering,binary processing,ima ge calibration module to establish a single pixel and the actual ma gnitude of the scale model,the fracture eigenval ue measure ment mod ule uses various calculation algorith ms to analyze two-valued image and obtains the crack detection results.(3)Experimental design and analysis: Design experime nts for the width of the crack.The experimental results show that,in the near distance measure ment mode,the measureme nt range is greater than 10 mm,the resolution is 0.01 mm,the ma xi mum value error is better than 0.02 mm,repeatability is not greater than 0.01mm;in the long distance measurement mode,the measureme nt range is l arger than 50 mm,the working distance is 2m~50 m,the resolution is 0.5mm a t the working distance of 50 m,the ma xi mum value error is better than 0.5 mm,rep eatability is not more tha n 0.05 mm.In addition,the effect of the calibration test on the measure ment results is tested,and the results show that the limit width errors introduced by each factor are within the maximum error range.