An advanced autofocus system for video camera using quasi condition reasoning

A novel autofocus (AF) system using quasicondition reasoning has been developed. This system consists of two main parts: a mountain-climbing servo (MCS) block and a quasicondition reasoning block. The operational basis of the MCS method and its performance limitation caused by external physical disturbance are shown. The quasicondition reasoning method, using a phase plane structured by the external disturbance components contained in the image signal, is described. It is concluded that the quasicondition reasoning method has made it possible to achieve an advanced AF system with high disturbance immunity.<
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