Automatic Mura Detection for Display Film Using Mask Filtering in Wavelet Transform

Jong-Seung PARK  Seung-Ho LEE  

Publication
IEICE TRANSACTIONS on Information and Systems   Vol.E98-D   No.3   pp.737-740
Publication Date: 2015/03/01
Online ISSN: 1745-1361
DOI: 10.1587/transinf.2014EDL8140
Type of Manuscript: LETTER
Category: Image Recognition, Computer Vision
Keyword: 
machine vision,  mura detection,  mura mask,  mask filtering,  

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Summary: 
In this letter, we present a method for automatic mura detection for display film using the efficient decision of cut-off frequency with DCT and mask filtering with wavelet transform. First, the background image including reflected light is estimated using DCT with adaptive cut-off frequency, and DWT is applied to background-removed images for generating mura mask. Then, a mura mask is generated by separating low-frequency noise in the approximation coefficients. Lastly, mura is detected by applying mura mask filtering to the detail coefficients. According to the comparison by Semu index, the results from the proposed method are superior to those from the existing methods. This indicates that the proposed method is high in reliability.