Coding of audio data in halftone images
Abstract: A new method for coding and decoding of audio data in halftone images is described and experimentally verified. Coding (modulation) is achieved by replacing printed dots by a set of two-dimensional characteristic symbols. Decoding (demodulation) is achieved by a bank of two-dimensional matched-filters. The system comprises source and channel coding, in order to compress and decompress the audio data and in order to avoid loss of data if the image is degraded physically. Up to 9 seconds of music in CD quality or 20 seconds of speech have been stored in an area of only 10cm2. Decoding is possible with a small hand-held scanner.