Implementation of an Automatic Focusing Algorithm Based on Spatial High Frequency Energy and Entropy
KANG Zong-ming,ZHANG Li,XIE Pan(Department of Electronic Engineering,Tsinghua University,Beijing 100084,China)
A new advanced automatic focusing algorithm is proposed.After discussing the principle how image is blurred by the lens system,we presented spatial high frequency energy and entropy as the sharpness criteria and analyzed their performance detailedly.Aiming at the limitation of conventional MCS,the concept of direction-test frame is proposed.The reliability,speed and sensitivity of auto focus are enhanced by using more definition criteria together and self-adjust step.The proposed algorithm has been successfully tested to be effective on a high definition image processing system developed by the authors.Experimental results demonstrate that the new criteria work according to the fact and the proposed algorithm.
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