Method and apparatus for selective block processing

A device (110) for embedding a watermark in selected blocks of a source data stream having a plurality of data elements, wherein the selected blocks meet a texture criterion that measures a variation of a selected characteristic associated with each data element, wherein the texture criterion is unrelated to any relationship between corresponding blocks of two different frames of the source data stream, the device comprising:

• a buffer circuit (115) for buffering and dividing the source data stream into a plurality of the selected blocks, wherein the block size is chosen arbitrarily with all blocks being of the same size;
• a block selector circuit (120, 170) coupled to the buffer circuit, the block selector circuit selecting the blocks of the source data stream that meet a substantially similar texture criterion, wherein the data input to the criterion function comes only from the block being tried for selection;
• and
• an embedder circuit (130, 140) coupled to the block selector circuit and an output of the buffer circuit, the embedder circuit embedding the watermark only in the selected blocks of arbitrary size that meet said substantially similar texture criterion.

A method of detecting a watermark embedded in selected blocks of a watermarked data stream having a plurality of data elements, wherein the selected blocks meet a texture criterion that measures a variation of a selected characteristic associated with each data element of the watermarked data stream, wherein the texture criterion is unrelated to any relationship between corresponding blocks of two different frames, the method comprising:

• dividing the watermarked data stream into a plurality of equally sized blocks as chosen arbitrarily in the embedding process reflected in the watermarked source data stream (145);
• selecting only the blocks that meet substantially similar texture criterion as that used in selecting the blocks for embedding the watermark, wherein the data input to the criterion function comes only from the block being tried for selection;
• and
• detecting the watermark only in the blocks that were embedded with the watermark and were selected by the selecting step thereby decreasing the time and number of operations necessary to process a given number of blocks.

A method of embedding and detecting a watermark in selected blocks of a source data stream having a plurality of data elements, wherein the selected blocks meet a substantially similar texture criterion that measures a variation of a selected characteristic associated with each data element, wherein the texture criterion is unrelated to any relationship between corresponding blocks of two different frames of the source data stream, the method comprising:

• dividing the source data stream into the selected blocks of substantially similar texture criterion, wherein the selected blocks are divided into a block size which is chosen arbitrarily with all blocks being of the same size;
• selecting only the blocks that meet said substantially similar texture criterion, wherein the data input to the criterion function comes only from the block being tried for selection embedding the watermark only in the selected blocks that meet the substantially similar texture criterion;
• in the process of detecting, selecting the blocks of the watermarked source data stream based on the same substantially similar texture criterion as that used in selecting the same blocks for embedding the watermark, wherein the size of the blocks is the same as arbitrarily chosen in the embedding process;
• and
• detecting the watermark only in the selected blocks.