ENCODING HIDDEN INFORMATION IN SPATIAL LINE FREQUENCIES

A method of encoding a hidden image in high frequency spatial frequencies of a line pattern of a host image. A set of host image spatial frequencies is generated based on a predefined mapping of a domain of a set of representative scalar values of the hidden image and a domain of the host image spatial frequencies. The line pattern of the host image is generated based on the set of host image spatial frequencies. The host image may be composed of tiles containing parallel line segments, with each tile encoding a corresponding one of the scalar values. The host image may be composed of a stochastic line pattern generated from a white noise image convolved with a space variable kernel based on the predefined domain mapping. The hidden image may be decoded algorithmically or optically in a single step.