On Tuesdays the USPTO issues new patents. Both of today's Spotlight Patents address various aspects of watermarking. Assigned to Toshiba, the first patent concerns techniques for watermark detection. Assigned to Fujitsu, the second patent concerns techniques for inserting a watermarking program into an image processing program.
An image size reduction unit reduces the image size of an input image signal, thereby generating a size-reduced image signal. A specific frequency component extraction unit extracts a specific frequency component signal from the size-reduced image signal. A phase controller controls the phase of the specific frequency component signal. A correlator computes a cross-correlation value between the phase-controlled specific frequency component signal and size-reduced image signal. A watermark information estimation unit estimates, from the cross-correlation value, watermark information embedded in the input image signal.
7,471,806, "Method, apparatus and computer program for inserting a watermarking program into an image processing program," assigned to Fujitsu (JP).
At every reproduction of a moving image, a tamper resistant module (TRM) randomly selects any one of plural electronic watermark inserting modules, and incorporates the module selected into an area randomly selected from among plural non-operation (NOP) areas in an MPEG expansion module. The module can be switched for each image in a series of the moving images. Since an algorithm for inserting the electronic watermark differs for each moving image or each image, elimination of the electronic watermark by means of analysis, particularly, complete elimination from all the images, is extremely difficult.