Near-lossless image authentication transparent to near-lossless coding
Roberto Caldelli, Giovanni Macaluso, F. Bartolini, Mauro Barni · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2004
In this paper attention is paid to the problem of remote-sensing image authentication by relying on a digital watermarking approach. Both transmission and storage is usually cumbersome for remote-sensing imagery and compression is unavoidable to make it feasible. In the case of multi-spectral images, used for classification purposes, too large valuemetric changes can cause miss-classification errors, so near-lossless compression is used to grant a given peak compression error. Similarly it is likely that also watermarking based authentication should grant such a maximum peak error and the requirements to be satisfied are: to allow valuemetric authentication, to control the peak watermark embedding error, to tolerate near-lossless compression. To achieve these requirements, a methodology has been designed by integrating into the standard JPEG-LS compression algorithm, by means of a stripe approach, a known authentication technique derived from Fridrich. This procedure points out two advantages: firstly, the produced bit-stream is perfectly compliant with the JPEG-LS standard, secondly, when the image has been decoded, it is always authenticated because information has been embedded in the reconstructed values. Near-lossless coding does not harm authentication procedure and robustness against different attacks is preserved. JPEG-LS coding/decoding has not got worse from the point of view of computational time.