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Region-adaptive Smear Removal Method Using Optical Black Region for CCD Sensors  

Han, Young-Seok (Institute of TMS Information Technology, Yonsei University)
Song, Ki-Sun (Institute of TMS Information Technology, Yonsei University)
Kang, Moon-Gi (Institute of TMS Information Technology, Yonsei University)
Publication Information
Journal of the Institute of Electronics Engineers of Korea SP / v.47, no.6, 2010 , pp. 107-116 More about this Journal
Abstract
Smear is a phenomenon that occurs when an extremely strong light source appears in the imaging system with CCD sensor. It occurs due to the signal charge transfer of CCD and appears as bright lines of noise emanating vertically (or horizontally) from the light source. For still images, smear can be reduced by using a mechanical shutter or special drive methods, but these techniques cannot be applied to image sequences. In this paper, we propose a smear removal method that can be applied to imaging systems for not only still images but also image sequences. The proposed method uses the optical black region(OBR) which is a group of pixels located in the boundary of CCD imaging sensors. Although the OBR is not exposed to light, it contains smear information caused by the charge transport. First, noise and the smear signal in the OBR is separated, and noise is removed to correctly estimate smear effect. Then, corrected OBR signal is uniformly subtracted to eliminate smear effect. Also, if saturation is occurred, the current pixel is substituted by weighted summation of neighboring pixels to improve the visual degradation. Experimental results show that the proposed algorithm outperforms the conventional methods.
Keywords
smear; CCD; charge transfer; optical black region; noise;
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