Abstract

Binary representations of sampled gray tone images and holograms are frequently used with success in optical information processing. Some of the binarization procedures used are based on the employment of carrier functions. Because of their passive nature, no object-dependent computations are necessary. In general these methods encounter the following handicap: to obtain a reasonable spatial resolution, a high carrier-frequency is chosen which implies a small number of sampling points with respect to the carrier period and, accordingly, a small number of representable gray levels. This trade-off can be avoided if one abandons the notion of a carrier period fixed to the underlying sampling raster. By a proper choice of carrier period and orientation with respect to the sampling raster it is possible to attain an optimization which includes a high spatial as well as high gray tone resolution.

© 1985 Optical Society of America