Analysis of the wavelet-based image difference algorithm for PCB inspection

The methodology and results regarding the use of wavelet transform and multiresolution analysis in automated visual printed circuit board (PCB) inspection provide the motivation for this research. In the paper, the wavelet-based image difference algorithm proposed is applied to a sample PCB image. The algorithm is applied by using a Haar wavelet where several different numbers of levels are considered. One conclusion from this paper is that the second level Haar wavelet transform should be selected for the application of visual PCB inspection.