A method and system for calibration of optical systems is disclosed. The system consists of a reference source (12), a spatial light modulator (26) for transmitting the reference source signal through non-imaging optics (30) and into the input of an optical system (36). The output of the optical system is then compared to the input signal and a correction is derived. The correction is stored and used real-time to adjust the output of the system to more accurately reflect the actual input signal.