Stain defect detection for mobile phone camera modules

In this paper, we present a stain defect detection algorithm based on the difference of window mean brightness. In particular, we use the maximum square value of the difference brightness in divided windows (MAXWDMS). Window shapes generally affect WDMS values and make stain images clearly distinguishable. The proposed method consists of three steps: window design, stain localization using MAXWDMS and setting the WDMS level. The proposed methodology has been successfully used in stain defect detection, achieving good detection rates in both quantitative evaluation and sensibility estimation. Experimental results show improved detection accuracy and a satisfactory processing time.