In a digital camera, an image pickup section feeds pixel data to a signal processor
that uses green pixel data as high-frequency luminance data. To generate luminance
for a subject pixel that is either a red pixel or a blue pixel, the signal processor
determines a direction of correlation by using the subject pixel and pixel data
identical in color with the subject pixel and adjoining it in horizontal and vertical
directions. The signal processor then generates, based on the subject pixel and
the pixel data used for the above decision, a color complementary to green as high-frequency
luminance data while attaching a flag indicative of the direction of correlation
to the pixel data. Further, by comparing flag patterns, the signal processor corrects
the above flag and then generates high-frequency luminance data from pixel data
positioned in a direction indicated by the flag. This obviates a difference in
level between nearby pixels in a direction of length.
