Patent ID: 6788801
Filing Date: 2004-09-07
Classification: G06T,H04N

Abstract:
The method for detecting information embedded in an image comprising:accepting an image; transforming the accepted image to form a plurality of transform coefficients which represent the accepted image; accepting an original image; transforming the original image to form a plurality of transform coefficients which represent the original image; computing a difference between the transform coefficients of the original image and the transform coefficients of the accepted image; determining a plurality of estimates of a watermark sequence, each estimate being determined from a different subset of the computed differences between transform coefficients; computing a plurality of indicators that the watermark sequence was encoded in the accepted image, each indicator being associated with a different one of the determined estimates of the watermark sequence; and determining an overall indicator that the watermark sequence was encoded in the accepted image from the plurality of indicators, wherein determining the plurality of estimates comprises determining a positive watermark estimator that estimates a positive watermark used to modify a subset of transform coefficients of the original image such that the magnitude of each of the coefficients is more likely to be increased than decreased.