Sharp-focus detector operating on doubled pixel signals e.g. for SLR camera - includes microprocessor for signal processing in accordance with calculated extreme value of correlation between two sequences

摘要

An image sensor (40) incorporating two rows of light receiving elements (4a, 4b) provides an analogue image signal to a driver circuit (50). The driver circuit generates control signals (51-53) for the image sensor. An amplifier (54) in the driver circuit feeds the microprocessor (60) with a stronger signal for conversion to digital form in synchronism with internally generated control signals (61-63). The digitised image is stored at successive addresses in write/read memory. Each pixel signal from each sensor is doubled and the focus is assessed from correlation of signals from both rows (4a, 4b). ADVANTAGE - Focus ascertained with higher precision by correlation of signals contg. double quantity of information.