Streak detection in mottled and noisy images

We describe a method for automatically detecting streaks in printed images using adaptive window-based image projections and mutual information. The proposed approach accepts a scanned image enclosing the defect and computes the projections across the entire image at different window sizes. The resulting traces collected from the projections are analyzed with a peak detection algorithm and subsequently correlated using normalized mutual information to pinpoint the location and width of streak(s). Finally, for a given peak, the window size is changed adaptively to identify and locate the intensity and length of the corresponding streak(s) while maximizing the signal-to-noise ratio. Results on synthetic and real-life images are provided to demonstrate the effectiveness of our proposed technique. (c) 2007 SPIE and IS&T.