Contrast enhanced amplified imaging by photorefractive recycling

Summary form only given. The techniques of image processing for contrast enhancement are well established, but nevertheless limited. Signal contrast may be improved by filtering out the object background resulting in a weak image. We demonstrate a system in which the ordinarily discarded background light is recycled for use as a pump source used to amplify the filtered signal using photorefractive two-beam coupling. High pass filtering can be used to visualize phase objects such as fingerprints. We present a qualitative comparison of the captured images of a fingerprint and show that the image which takes advantage of optical pre-amplification by recycling, possesses superior characteristics and preserves image contrast. We envision that the technique of phase contrast microscopy may be supplemented by our recycling mechanism in much the same way, so as to substantially increase the throughput efficiency of ordinary phase contrast microscopes.