New patents are issued by the USPTO on Tuesdays. Both of this week's Spotlight Patents are assigned to Cisco and both address aspects of digital watermarking. The first patent concerns techniques for embedding data in video frames. The second patents concerns techniques for an LFSR [linear feedback shift register] watermark system.
9,208,534, "System and method for embedding data," assigned to Cisco.
In one embodiment, a watermark is embedded in a sequence of video frames, for each one of the video frames, a set of N rectangular patches, two palettes of pixel values in a selected color space, such that the two palettes are denoted as P0 and P1, and P0.noteq.P1, and in each one of the N patches a processor which chooses one of P0 and P1 according to a value of a payload bit to be encoded, a calculator which calculates one of a variance of pixel values in the frame, and edginess for the pixel values in the frame, thereby determining a calculated value, and a processor which determines if the calculated value is beneath a given threshold value, if the calculated value is beneath the given threshold value the processor is operative to calculate a function of the pixel values, the closest value to a result of the calculation of the function in the chosen palette is chosen, and a replacer which replaces the pixel values within the patch with the chosen closest value. Related systems, apparatus and methods are also described.
9,208,352, "LFSR watermark system," assigned to Cisco.
In one embodiment, a system including a processor is operative to receive a content item including a watermark encoding a series of data values of an output stream of a linear feedback shift register initialized with a seed including an information element and an assurance value, the shift register having a plurality of states each including a first and second value, identify at least part of the watermark in the content item, extract at least some of the data values from the at least part of the identified watermark, process at least some of the extracted data values yielding the initial state of shift register, and authenticate the first value of the initial state using the second value of the initial state in order to confirm that the first value is indeed the information element included in the seed processed by the shift register.