A Method for Reconstruction of Solder Joint Surface

Inspection of solder joint is a critical step in the assembly of Printed Circuit Board (PCB) which requires high reliability. Non-destructive inspection technology based on image captured by Charge Couple Device (CCD) has been widely used in a production of PCB because of their excellent characters. This paper deals with the reconstruction of the solder jointpsilas surface in PCB based on shape form shading technology. Shape-from-shading (SFS) is an important non-contact measurement method that can be affected by the noise combined in image, so a Gaussian Smoothing filter is used pre-reconstruction. Nowadays, more and more researchers pay more attention to 3-D solder joint inspection. In this paper, compared to other measurement methods, the advantages of SFS method are analyzed firstly. Then, theory of SFS method is introduced. To overcome the disadvantages existing in conventional SFS methods, some improved algorithms are provided and proved by experiments. Experimental results reveal that the proposed method shows practical value in solder joint inspection.