Proceedings of SPIE
To characterize CMOS imagers an LED-based multi-spectral optical source system was designed and tested which is capable of illuminating a 15-mm field at a conjugate distance of 50 mm with 98 percent uniformity. The calibration source is comprised of an array of RGB semiconductor LEDs, an IR cutoff filter and a diffusing lens. The system is integrated into an anodized aluminum housing. The spatial uniformity of the LED optical source was compared with an optical integrating sphere and an Optoliner projection system.
Hancock, Jed J.; Baker, Doran J.; and Ware, Gene A., "An Optical Source for Characterizing CMOS Imagers" (2004). Space Dynamics Lab Publications. Paper 54.