Digital watermarking system using scrambling method
AssigneeSanyo Electric Co., Ltd.
InventorAkiomi Kunisa
Life of this patent
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Abstract
An encoding apparatus that embeds a watermark in host data is provided. A multiplexer generates a plurality of bit sequences by adding initial data to the head of the watermark. A scrambler scrambles a plurality of the bit sequences respectively and generates a plurality of scrambled watermarks. An embedder embeds a plurality of the scrambled watermarks in the host data and generates a plurality of candidate watermarked host data. A signal-to-noise ratio calculator evaluates the robustness of the watermarks hidden in the respective candidate watermarked host data. A selector selects one candidate that has the highest level of the robustness as a final watermarked host data.
Claims29
A digital watermark embedding method comprising scrambling a digital watermark to be embedded in host data and thereby generating a plurality of candidate watermarks, and evaluating robustness of the respective candidate watermarks when the respective candidate watermarks are embedded in the host data, and obtaining watermarked host data in which one of the candidate watermarks is embedded with a high level of robustness.
A digital watermark embedding method comprising generating a plurality of candidate locations of host data in which a digital watermark is embedded, and evaluating robustness of the watermark when the watermark is embedded in the respective candidate locations, and obtaining watermarked host data in which the watermark is embedded with a high level of robustness in one of the candidate locations.
An encoding apparatus comprising:
- a scrambling unit which scrambles a digital watermark to be embedded in host data and generates a plurality of candidate watermarks;
- an embedding unit which embeds the respective candidate watermarks in the host data and generates a plurality of candidate watermarked host data;
- an evaluating unit which evaluates robustness of the respective candidate watermarks hidden in the respective candidate watermarked host data;
- and
- a selecting unit which selects and outputs one of the plurality of the candidate watermarked host data according to the evaluated robustness.
An encoding apparatus comprising:
- a location information generating unit which generates a plurality of candidate locations of host data in which a digital watermark is to be embedded;
- an embedding unit which embeds the watermark in the respective candidate locations of the host data and generates a plurality of candidate watermarked host data;
- an evaluating unit which evaluates robustness of the digital watermark embedded in the respective candidate watermarked host data;
- and
- a selecting unit which selects and outputs one of the plurality of the candidate watermarked host data according to the evaluated robustness.
A decoding apparatus comprising:
- an extracting unit which extracts a scrambled watermark from host data in which a digital watermark is supposed to have been embedded;
- and
- a descrambling unit which descrambles the scrambled watermark by performing a convolutional operation on the watermark using identification data on the watermark.
A decoding apparatus comprising:
- a location information generating unit which generates a plurality of candidate locations of host data in which a digital watermark is supposed to have been embedded;
- an extracting unit which extracts a plurality of candidate watermarks embedded in the host data according to the respective candidate locations;
- a checking unit which checks the plurality of the extracted candidate watermarks with an anticipated watermark;
- and
- a selecting unit which selects and outputs one of the candidate watermarks according to a checking result produced by the checking unit.
A decoding apparatus comprising:
- a location information generating unit which obtains a secret key which indicates identification data on a location of a host data in which a digital watermark is supposed to have been embedded, and identifies the location by decrypting the secret key and referring to a table which associates the identification data with a random location of the host data;
- and
- an extracting unit which extracts a watermark from the host data according to the identified location.
A host data structure in which a digital watermark is hidden, comprising an embedded watermark which is scrambled by a predefined scrambling method and identification data necessary for descrambling the scrambled watermark which are incorporated as a part of the scrambled watermark.
A computer program executable by a computer, the program comprising:
- generating a plurality of candidate watermarks by scrambling a digital watermark to be embedded in host data;
- generating a plurality of candidate watermarked host data by embedding the respective candidate watermarks in the host data;
- evaluating robustness of the respective candidate watermarks hidden in the respective candidate watermarked host data;
- and
- selecting one of the plurality of the candidate watermarked host data according to the evaluated robustness.
A computer program executable by a computer, the program comprising:
- generating a plurality of candidate locations of host data in which a digital watermark is embedded;
- generating a plurality of candidate watermarked host data by embedding the watermark in the respective candidate locations of the host data;
- evaluating robustness of the watermark hidden in the respective watermarked host data;
- and
- selecting one of the plurality of the candidate watermarked host data according to the evaluated robustness.
Dependencies are inferred from the claim text.