Imaging apparatus with low-illuminance imaging capability

摘要

Low illuminance shooting is achieved by raising the gain or sensitivity through noise reduction while mitigating the deterioration in resolution. An image signal that has been imaged by CCD and amplified CDS is converted into a series of digital pixel values. A weighted moving average of a current pixel value and pixel values of at least two pixels spatially adjacent to the pixel of the current pixel value are calculated. The weighted moving average is divided by a division factor smaller than the sum of weights used in the weighted moving average calculation. If the image signal is smaller than a predetermined value, a selector supplies the divided weighted moving average as the current pixel value to the next stage. This enables not only a gain increase due to noise reduction but also a mitigation of the deterioration in resolution.