1. An image-taking system comprising: a solid-state imaging device for taking an image of an object; image-forming means for forming a luminance-component image and a color-component image of the object serially on said solid-state imaging device; generating means being moved such that every point on an image formed on said solid-state imaging device moves on the circumferences of a circle having a radius, and for generating optical transfer functions; control means for controlling said generating means for changing said radius alternately to change the optical transfer functions generated by said generating means so that a luminance-component image is formed at a different radius from a color-component image; storing means for storing the luminance-component image and the color-component image in order, formed with two or more different optical transfer functions generated by said generating means; and combining means for forming a single image by combining the luminance-component image and the color-component image readout from said storing means according to an image-generating operation.