New patents are issued by the PTO on Tuesdays. Today's Spotlight Patents concern aspects of digital fingerprinting and digital watermarking. Assigned to Amazon, the first patent addresses techniques for checking the integrity of a document by comparing a prior fingerprint of a document with a result of a fingerprint function applied to content of the document. Assigned to TLS, the second patent addresses techniques for inserting watermarks into audio signals that have speech-like properties.
9,633,062, "Document fingerprints and templates," assigned to Amazon.
Aspects related to fingerprints and templates of documents are described. In one embodiment, the integrity of a document is checked by comparing a prior fingerprint of a document with a result of a fingerprint function applied to content of the document. When the fingerprint of the document is consistent with the result of the fingerprint function, a standard form related to the document is identified. In this context, a synopsis of the standard document may be provided. In other embodiments, when the prior fingerprint of the document is inconsistent with the result of the fingerprint function, one or more paragraphs of the document may be checked for consistency by comparing prior fingerprints of the paragraphs with results of a fingerprint function applied to the paragraphs. Common meaning statements for one or more of the paragraphs may also be identified and provided as part of the synopsis of the document.
9,626,977, "Inserting watermarks into audio signals that have speech-like properties," assigned to TLS Corp.
A method for a machine or group of machines to watermark an audio signal includes receiving an audio signal and a watermark signal including multiple symbols, and inserting at least some of the multiple symbols in multiple spectral channels of the audio signal, each spectral channel corresponding to a different frequency range. Optimization of the design incorporates minimizing the human auditory system perceiving the watermark channels by taking into account perceptual time-frequency masking, pattern detection of watermarking messages, the statistics of worst case program content such as speech, and speech-like programs.