Abstract: A hardware approach based on looking-up table was proposed to implement image fusion by transferring natural daylight colors to multi-band images in the l space, and consequently a long-distance infrared and low light level (LLL)/visible fusion imaging system was developed. An LLL camera and a CCD fusing with an infrared thermal imager in the night and day respectively, which ensured the system to keep 24-hour fusion imaging. The colors in the resulting colorized multiband night-time images closely resemble the colors in the daytime color reference image and object colors remain good color constancy. Two fields of view were designed, which satisfied the need of searching in the big field of view and tracking in the little field of view. A laser rangefinder was embedded in this system to satisfy the need of measuring distance. Preliminary field trials demonstrate the potential of the system for applications like surveillance, navigation and target detection.