Specular Surface Cracks Detection Based On Image Processing

Industrial defect detection is a key part in industrial production,which improves product quality,increasing brand reputation greatly.China is the world's largest manufacturing country,but defect detection work is still mainly artificial at present,and there is still a big gap between the developed countries.With the rise of human resources cost,automatic industrial defect detection will be an inevitable trend in the future.As one of the common defects,the specular surface defects are difficult to detect because of non-uniform illumination,and sometimes it is visible only at a certain angle of view.Aiming at detecting defects on specular surface,this paper designs a set of practical system which can classify the products based on the image processing method.It realizes the high-speed and high-efficiency detection of the products.This thesis is divided into four parts:(1)Illumination design.Through Phong model,simulations of lighting are carried out for better images.In trials and errors,finally we obtained an almost perfect solution,which is vertical illumination with coaxial light,providing uniform and stable background and highlighting the defects regardless of different angles.(2)Product area extraction.Through the high-resolution industrial CCD,the algorithm first solves the problem of light unevenness by illumination compensation.Then get the product location by Otsu,which shrinks the detection area.(3)Defect detection.Canny edge detection,morphological dilation algorithm and morphological skeleton algorithm are used to extract the complete defect target.Then the morphological corrosion and connectivity component extraction statistics were used to obtain the suspected defects.(4)Defect recognition.According to the geometric parameters,rough classification is classified as line defect and hole defect,and then the product grade classification standard table is used to subdivide each kind of defect,and the product grade is finally divided to decide whether the product is qualified,and output the failure reason.