An illumination system includes an illumination source configured to emit illumination light and a dispersive optical element configured to generate an angularly dispersed optical signal from the illumination light that is used to generate a spectral image. A digital micro-mirror device (DMD) includes an array of reflective elements that receive the spectral image and direct a portion of the spectral image to an integrating sphere. A controller is configured to calculate a subset of an array of reflective elements of the DMD to activate based on a target illumination output signal using a calibration model of the illumination system. The controller is also configured to activate the subset of the array of reflective elements to change the portion of the spectral image directed to the integrating sphere to generate an illumination output signal that substantially matches the target illumination output signal.