FIG. 3.

Flat field correction for the camera and lens. (A): The setup for the flat field correction procedure. CCD camera with f/1.4 lens was positioned against the light output port of the integrating sphere. The filtered light source provided the input illumination. (B): The flat field correction map. The green box outlines the interested imaging area for in vivo or phantom experiment. (C): Profiles along the dotted line indicated in panel (B). The profiles for 590–650 nm are essentially overlapped. (D)–(F) show the verification of the flat field correction. (D): An image of the integrating sphere output port prior to flat field correction. (E): The same image after the correction. (F): The profiles plotted along the line in panels (D) (raw data) and (E) (corrected).