IMPROVEMENTS IN OR RELATING TO MERGED FIELD OPERATION OF AN IMAGE SENSOR IN A STILL VIDEO CAMERA

摘要

A driving circuit (30) generates multi-phase signals for operating the vertical charge-coupled registers (V1, V2...) of an interline-transfer image sensor (12). Though having full-frame still capability, the sensor (12) is included in a still video camera for single-field recording. After a still exposure is completed, the phase signals (XV1...XV4) applied to the vertical registers generate an array of charge wells in the registers alongside the photoelectric elements (P1, P2) corresponding to each field. The image charges residing in these elements transfer to the registers as separate fields, where they are merged as one field in order to increase the photosensitivity for a single-field still recording. Such increased photosensitivity is translated into increased photographic range by controlling the exposure of the sensor (12) to accord with the increased image charge by, for example, reducing the exposure time provided by the sensor or the optical aperture presented to the image sensor. In this manner, the "speed" of the sensor is increased for merged field operation.