Solid-state image pickup apparatus for producing image signals with pixel signals mixed in a horizontal direction and a signal reading method for the same

摘要

A solid-state image pickup apparatus includes a timing signal feeding section for outputting signals assigned to a preliminary pickup mode as well as signals assigned to an actual pickup mode that follows the preliminary pickup mode. In the preliminary pickup mode, signal charges read out of photodiodes are mixed and read out via a horizontal transfer path as if they were reduced in the horizontal direction, thereby increasing a substantial transfer rate. A signal processor includes a preliminary pickup processing circuit. The preliminary pickup processing circuit performs calculations with digital data derived from the mixed signal charges. As a result, the representative primary colors R (red), G (green) and B (blue) of a plurality of signal charges are produced from the mixed, reduced signals by approximation or within a preselected horizontal range. A luminance signal and chrominance signals are then produced from the above colors R, G and B. The apparatus successfully reduces signal reading time and enhances image quality.