White-Light Prefiltering For Real-Time Digital Image Transmission Of Still And Moving Color Video Images
G. Eichmann, Robert C. Stirbl · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1981
Signal-dependent noise encountered when sampling video signals at low sampling rate, while using an adaptive video delta modulator both as a source encoder and a video digitizer, is combated by using a white-light reflective transform optical preprocessor. While the white-light preprocessor works on black and white images, its main advantage is that it can simultaneously process, using a single source, many color channels. Further, the relative lack of both spatial and temporal coherence aids in reducing speckle and interference noise effects. Experimental results on color video images, that have been preprocessed using a white-light optical transform preprocessor and digitally encoded by sampling with an adaptive delta modulator close to the Nyquist rate, are presented.