Abstract: Techniques for improving detection of watermarks in content that has undergone a lossy transformation. One of the techniques is used when the message that is contained in a watermark belonging to a digital representation that is derived from an original watermarked digital representation cannot be decoded. The technique obtains information about the watermark by comparing the watermark vector for the watermark that cannot be decoded with a replica of the watermark vector from the original watermarked digital representation. The replica is made using the message. Depending on the degree of similarity, the watermark's presence and some of its characteristics may be determined. Another technique improves the robustness of watermarks that are used for authentication by employing a short (even single-bit) watermark vector to make the watermark and using the message needed for the authentication to determine where the watermark is located in the digital representation.

Abstract: Techniques for improving detection of watermarks in content that has undergone a lossy transformation. One of the techniques is used when the message that is contained in a watermark belonging to a digital representation that is derived from an original watermarked digital representation cannot be decoded. The technique obtains information about the watermark by comparing the watermark vector for the watermark that cannot be decoded with a replica of the watermark vector from the original watermarked digital representation. The replica is made using the message. Depending on the degree of similarity, the watermark's presence and some of its characteristics may be determined. Another technique improves the robustness of watermarks that are used for authentication by employing a short (even single-bit) watermark vector to make the watermark and using the message needed for the authentication to determine where the watermark is located in the digital representation.

Abstract: Techniques for incorporating authentication information into digital representations of objects and using the authentication information to authenticate the objects. The authentication information may be made from information in one portion of the digital representation and incorporated into another portion of the digital representation that does not overlap the first portion. Where the digital representation is made into an analog form and that in turn is made into a digital representation and the second digital representation is verified, the two portions must further be non-overlapping in the analog form. The information from which the authentication information is made may exist at many levels: representations of physical effects produced by the object, representations of features of the object, codes that represent the object's contents, and representations of descriptions of the object. Also disclosed are a verification server and techniques for reducing errors by an OCR.