Patent Document ID: 6144408
Application ID: 08995955
Patent Status: 1

Claim One:
1. A electronic imaging device employing black pattern correction for dark current in an image sensor, said dark current imposing a fixed-pattern noise on image signals obtained by exposing the image sensor to image light from a subject, said imaging device comprising: a charge transfer image sensor composed of image pixels having a characteristic black pattern of dark current corresponding to the array of pixels in the sensor, the amplitude of the dark current for each pixel being dependent upon exposure time; means for capturing a reference dark frame exposure from the image sensor in the absence of light and generating dark frame pixel values therefrom; an exposure section for regulating the exposure time of the image light upon the image sensor and providing a corresponding plurality of image frame exposures in the presence of the image light, which is non-uniform across the sensor, the image sensor generating a corresponding plurality of image frames each comprised of image frame pixel values representative of the non-uniform image light; and a processor section for generating a unique black pattern dark current correction factor for each image frame based on processing both the dark frame pixel values for the reference dark frame exposure and the image frame pixel values for each image frame exposure, said processor section applying each black pattern correction factor to the image frame pixel values for each of the plurality of image frames to obtain corrected image frame pixel values that are modified for the black pattern due to dark current in the image sensor, wherein a single reference dark frame exposure is used in the correction of many image frame exposures.