Fast optical thresholding with an array of optoelectronic transceiver elements

In this letter, we present an optoelectronic system for fast gray-level image decomposition into binary slices. To perform thresholding, we are making use of the differential nature of optical thyristors and compare the light level of the image pixels to that of a reference intensity. As input a gray-level image was generated using a nematic liquid crystal spatial light modulator (SLM) and as a reference intensity a VCSEL light source combined with a diffractive fan-out element was used. We also introduced a compact, large field of view telecentric optical system based on gradient refractive index lenses to image between the SLM and the array. A frame rate decomposition of a six gray-level image has been obtained at 1.8 kHz. Future prospects for system improvements are discussed.