Image processing methods using reversible watermarking
AssigneeDigimarc Corporation
InventorsJun Tian, John Stach, Neil E. Lofgren
Life of this patent
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Abstract
The ability to remove a watermark from an encoded image opens the possibility of various novel applications. Several such applications are detailed. One employs a reversible watermark in conjunction with a second (robust) watermark. In this arrangement, the payload of the reversible watermark conveys information about the robust watermark (e.g., encoding parameters, or an error signal), permitting removal of the robust watermark from an uncorrupted encoded image. By such arrangements, the encoded image can be fully restored to its pristine, unencoded state even if several different watermarks have been applied.
Claims16
A method comprising:
- encoding a content object with a first, robust digital watermark, the first watermark conveying a first payload of one or more digital symbols, the first watermark being decodable notwithstanding at least certain corruptions of the encoded object;
- encoding the content object with a second digital watermark, the second watermark conveying a second payload of one or more digital symbols, the second watermark being encoded using a process that is reversible given an uncorrupted encoded content object and the second payload;
- wherein the second payload conveys data enabling substantial removal of the robust digital watermark from an uncorrupted version of the encoded content object.
A method comprising:
- receiving a content object encoded with first and second digital watermarks, the first and second watermarks conveying first and second payloads, respectively;
- decoding the first watermark to obtain the first payload, the first payload including first data;
- decoding the second watermark to obtain the second payload;
- processing the content object to remove the first watermark therefrom, yielding an intermediately-processed content object;
- through use of the first data, processing the intermediately-processed content object to remove the second watermark therefrom, yielding a processed content object;
- wherein said processed content object corresponds to the received content object without any watermarks.
A method of processing a content object encoded with frail and robust digital watermarks, each watermark conveying a data payload, the robust watermark being adapted to survive at least certain object corruptions, the method comprising:
- removing the robust watermark from the content object to provide an intermediate object;
- and
- decoding, from the intermediate object, the payload conveyed by the frail watermark.
Dependencies are inferred from the claim text.