Reversible color-to-gray mapping using subband domain texturization

— The concept of reversible conversion of color images to gray ones has been recently introduced. Colors are mapped to textures and from the textures the receiver can recover the colors. This was done using the wavelet transform and replacing highfrequency subbands by the down-sampled chrominance planes. The idea is to print a color image with a black and white printer and, then, at a later time, to scan the document and recover colors. In this paper, we propose to use a more robust method, i.e. more resistant to the print-scan noise. We propose to use a largely redundant representation of the chrominance, embedding them into multiple subbands of a general subband transform. In other words, we spread the chrominance onto many subbands. We show theoretically that for minimizing the variance of the error caused by noise, the chrominance should be replicated into many subbands and not linearly combined. We carry a noise analysis to determine bounds to guide us on how many subbands to em...

• Type: Journal
• Year: 2010
• Where: PRL
• Authors: Ricardo L. de Queiroz
• Keywords: Chrominance, Color Image, Down-sampled Chrominance Planes, PRL 2010