A method is disclosed for converting color images to textured monochrome
images such that image regions with similar luminance but different
chrominance look different when converted to black-and-white to preserve
color information therein. This texture-encoded color information can be
extracted at a later time to reconstitute the original color image. The
present method involves first converting the color image to a
luminance-chrominance colorspace. The chrominance data is decomposed into
4 channels of chrominance. A wavelet transformation of the luminance
channel is preformed. Scaled chrominance channels are then mapped to a
number of wavelet sub-bands. Once mapped, the wavelet transform is
inverted to generate textures proportional to the original colors of the
color image having an amplitude proportional to the chroma of the
original color. The black-and-white image is embedded with this texture
information into the image's grayscale component. In order to retrieve
the color image from the textured grayscale image, a wavelet transform
regenerates the scaled chrominance channels mapped therein. Those wavelet
sub-bands comprising embedded chroma are extracted and scaled to the size
of the original image. The remaining sub-bands are inverted to produce
the Y-image thereof. Separate images now exist in Y, Cr, and Cb. The
recombination of the YCbCr images produce the colored image that was
previously embedded into the grayscale components of the textured
black-and-white image.