Solder Joints Detection Method Based on Surface Recovery

Machine vision has been widely used in various industrial productions. However, the study for solder joints detection is not enough. This paper presents a solder joints detection method based on surface recovery. For a single gray-scale image, using shape-from-shading (SFS) technology, the surface of the solder joints is recovered. According to the shape distribution, the quality of solder joints is discriminated. In order to improve the accuracy of recovery for real images, hybrid illumination model is introduced and a reflection-component estimation method based on simulated annealing algorithm is designed. Then recovery process of the algorithm is improved. Compared to other detection methods based on two-dimensional images, this method provides more information about explicit physical meaning and make detailed quantitative analysis for solder joints easier. At the same time, even for defect that is difficult to detect, this method also has important research value.