Compact image scanner with large depth of field by compound eye system.

A compact image scanner is designed by using a compound eye system with plural optical units in which a ray path is folded by reflective optics. The optical units are aligned in two lines and take each image of a separated field of view (FOV), slightly overlapped. Since the optical units are telecentric in the object space and the magnification ratio is constant regardless of the object distance, the separated pieces of a total image are easily combined with each other even in the defocused position.