First and second optical images of an object are respectively taken using two optical filters, having different optical transfer properties, which are placed one at a time in the optical path of the taken images. The first and second optical images are converted to first and second memories, respectively. The first digital signal indicative of the first optical image is provided to a luminance-signal generator which produces a luminance signal. The second digital signal indicative of the second optical image is provided to a color-signal generator which produces a color signal. A combining unit combines the luminance signal and the color signal to produce a single image signal of the object having a suppressed color moire. An image reproduction device receives the single image signal to reproduce the image of the object.