On Tuesdays the USPTO issues new patents. Both of today's Spotlight Patents address the use of watermarking. Assigned to MY EZ Communcations, the first patent concerns hybrid digital watermarking for video authentication. Assigned to Ricoh, the second patent concerns a durable and undecipherable digital watermarking technique and detection of unauthorized use.
7,409,556, "Hybrid digital watermarking for video authentication," assigned to MY EZ Communications.
A hybrid digital watermarking system for video authentication includes an authenticated acquisition subsystem for digitally watermarking video data and a video management subsystem in signal communication with the authenticated acquisition subsystem for verifying the digitally watermarked video data, where the authenticated acquisition subsystem may include a watermarking device for applying each of an identity signature and a control signature to the video data within a hybrid digital watermark, and the hybrid digital watermark may achieve progressively varying robustness by means of error-correcting signature coding and/or rate-distortion guided bit embedding.
7,409,060, "Durable and undecipherable digital watermarking technique and detection of unauthorized use," assigned to Ricoh (JP).
A digital watermarking technique is disclosed, in which image data are converted to frequency components through discrete wavelet transform and quantized into a set of quantized coefficients, which are then divided into a plurality of blocks. A digital watermark is embedded in the quantized coefficients by performing ON/OFF adjustment of bit information, such that the relation between natural number T and the bit information defined by N (N is an even number) significant bits Qnm (x, y) of the m-th bit plane of the n-th block satisfies the ON state represented by equation (1), or the OFF state represented by equation (2), depending on whether the hash value of the n-th block is odd or even. Then the quantized coefficients are encoded to produce a code stream.