Abstract

Gray-level image processors need more than just two bits for the inputs. For the specific case of image addition, it is necessary for the carry to propagate so as to yield the correct binary output. In the original optical shadow-casting work of Tanida and Ichioka,¹ this was realized by copying the input bits of the gray-level images into different spatial locations, but the scheme finally resulted in a nonbinary analog output. In the current work using a polarization-encoded optical shadow-casting system,² the carry propagation is accomplished simply by means of encoding (using polarization codes) the inputs and sources. Both serial and parallel outputs are shown to be realizable using the polarization-encoded optical shadow-casting system. The system is unique in that it acts like an associative memory wherein certain portions of the available memory locations are shared by more than one output. The associative nature of mapping of information in the input pixel subcells makes this system highly efficient in terms of memory saving.

© 1988 Optical Society of America