3D Shape Reconstruction based on Directional LED lights

A novel algorithm is presented in this paper for solder paste inspection. The proposed methodology is based on a specially designed directional LED lighting to highlight the geometrical features of the solder paste block. Solder paste inspection and shape reconstruction are then carried out based on the highlighted features. An algorithm for 3D shape reconstruction of solder paste is developed. The process is carried out by calculating a set of surface heights for the solder paste block. The estimated shape of the solder paste block is represented by the calculated set of surface heights. To improve the accuracy of the estimation, parameter optimization has been carried out to search for an optimal set of algorithm parameters using the actual solder paste shape.