Micro Quality Inspection Technology Of Stone Surface

With the development of domestic architectural decoration industry and the growing concern about low carbon environmental awareness,the natural stone is widely used in architectural decoration,at the same time,enterprise have increased the demand for stone quality inspection technology.Three-dimensional measurement and evaluation of the surface micro-topography is a hot topic in the field of surface science.Three dimensional reconstruction of the surface topography have great significance for the study of the surface observation,measurement and performance.A kind of 3D reconstruction method of stone slabs surface was proposed based on the study of the theories and key points of the depth from focus(DFF).The micro-quality detection of the stone plate surface was realized.It was the main research content of the thesis using monocular camera combined computer image processing technology to detect the micro quality of the stone surface,and the study of non-contact surface microstructure quality inspection technology was achieved.According to the design requirements,the hardware of the system was selected,that including light source,CCD industrial camera,image acquisition card,system structure and so on.(1)The stones image collected by CCD industrial camera transferred to the computer.By using the method of image processing,the pretreatment of stones image was completed,which provided a basis for the subsequent surface quality detection.(2)Using the method of servo motor to control the moving of the camera along the Z axis,the image of microscopic sequence was obtained and the Z axis value of the image was recorded.The improved Laplacian fusion method was used to extract clear region of each microscopic sequence image.Extract clear region were fused into an approximate full-focus image and calculated by focus measure.The precise depth information was determined for each point by Gaussian interpolation.Three dimensional surface reconstruct was carried out by using the height information,and the 3D model of the micro sample was simulated.Software written calculated the two-dimensional roughness and 3D roughness by using the height data.(3)Combined with the transformation between RGB and HIS color model,the digital image processing technology was used to calculate reflectivity mathematical model.The average reflectivity of the measured stone surface was calculated by reflectivity mathematical model.Then the surface gloss was obtained.The rationality and correctness of the method was verified through the comparison of the surface quality parameters of the contact and non contact measurement.Therefore,the three dimensional reconstruction principle of focusing synthesis and the surface gloss calculation model could be used for surface quality detection.The detection system could provide a basic platform for the future stone decoration design,increase the utilization rate of stone,reduce labor cost and management cost of stone production enterprise.