Automatic focusing device employing a frequency domain representation of a digital video signal

Abstract

An automatic focusing device has an A/D converter for converting a supplied video signal to a digital signal; an orthogonal converter for converting a video signal transmitted from the A/D converter to a signal indicative of a frequency component region; and a control section for producing a control signal for performing a focusing operation based on information of the frequency component transmitted from the orthogonal converter. The orthogonal converter performs a discrete cosine transformation with respect to the digitally converted video signal. The orthogonal converter transmits low to high frequency components from the digitally converted video signal. The control section transmits the control signal for performing a focusing operation based on an arbitrary component of the frequency components transmitted from the orthogonal converter. A circuit for performing the focusing operation may be constructed on the basis of a plurality of frequency components.

Dependencies are inferred from the claim text.