1. Field of the Invention
This invention relates to a noise reduction apparatus, a method and program for controlling this apparatus, and an image sensing device and digital camera having this apparatus.
2. Description of the Related Art
CCDs used in digital still cameras are continuing to be improved in terms of number of pixels and sensitivity. The influence of noise, therefore, has become a problem.
Using a low-pass filter or median filter, etc., to remove noise from a video signal obtained by image sensing has been considered (see the specification of Japanese Patent Application Laid-Open No. 2004-235472). The removal of noise from an image without detracting from image sharpness has also been considered (see the specification of Japanese Patent Application Laid-Open No. 2002-222416). There is also prior art for detecting an edge based upon neighboring pixels and suppressing a decline in resolution (see the specification of Japanese Patent Application Laid-Open No. 2005-303731).
It is still difficult, however, to remove noise completely.