Every Tuesday the USPTO publishes newly issued patents. Both of today's Spotlight Patents concern various aspects of watermarking. Assigned to Wistaria Trading (Scott Moskowitz), the first patent concerns techniques for watermarking a content signal. Assigned to the Electronics and Telecommunications Research Institute (KR), the second patent concerns techniques for embedding and extracting digital watermark on lowest wavelet subband
7,343,492, "Method and system for digital watermarking," assigned to Wistaria Trading (Scott Moskowitz).
A method for applying a digital watermark to a content signal is disclosed. In accordance with such a method, a watermarking key is identified. The watermarking key includes a binary sequence and information describing application of that binary sequence to the content signal. The digital watermark is then encoded within the content signal at one or more locations determined by the watermarking key.
7,343,025, "Method for embedding and extracting digital watermark on lowest wavelet subband," assigned to Electronics and Telecommunications Research Institute (KR)
A for embedding a digital watermark on a wavelet lowest subband includes: setting a DC component region of a multi-stage wavelet-transformed original copy image to a watermark embedment region, and high-frequency filtering an original picture LL.sub.n of the embedment region; generating index information for designating a pixel position, and a watermark sequence to be embedded; calculating an embedment strength .lamda. for each position of the watermark embedment region; in case the watermark sequence is sequentially embedded on an embedded position designated by the index information, mutually comparing the original picture LL.sub.n coefficient value for each embedded position with a mirror picture LL.sub.n' coefficient value, and then altering the original picture LL.sub.n coefficient value; and in case the original picture LL.sub.n coefficient value is differentiated above a predetermined value with reference to the coffesponding embedment strength .lamda., skipping the watermark embedment for the position.