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Mid frequency - DCT focus measure operator for the robust autofocus  

Lee, Sang-Yong (Korea University)
Park, Sang-Soo (Korea University)
Kim, Soo-Won (Korea University)
Publication Information
Journal of the Institute of Electronics Engineers of Korea SD / v.43, no.12, 2006 , pp. 8-14 More about this Journal
Abstract
This paper proposed noise insensitive 4*4 mid frequency-OCT (MF-DCT) focus measure operator. Proposed operator enhanced low power 8*8 MDCT operator to have 4*4 rotationally same form for Gaussian noise. MF-DCT operator acting like band-pass filter suppresses both low-frequency signal useless for focus measure and high-frequency signal affected by impulsive noise. Also it is proved to be linear because it uses the energy of band-pass filtered signal as focus measure. Experimental result shows its superiority by comparing AUM with traditional operators.
Keywords
Autofocus; Focus measure; Impulsive noise; Gaussian noise; AUM;
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