초록 ▼

A method is provided which comprises providing a block of IWT (integer wavelet transform) coefficients for preferably one high frequency sub-band of an image; determining a mean value of said coefficients within said block; and establishing an encoded mean value to embed one of a logical-0 bit value

A method is provided which comprises providing a block of IWT (integer wavelet transform) coefficients for preferably one high frequency sub-band of an image; determining a mean value of said coefficients within said block; and establishing an encoded mean value to embed one of a logical-0 bit value and a logical-1 bit into said first block.

대표청구항 ▼

The invention claimed is: 1. A method of embedding into an image additional information that is not part of the image, the method comprising: dividing a frequency sub-band of the image into a plurality of blocks and providing a block of IWT (integer wavelet transform) coefficients for one of the pl

The invention claimed is: 1. A method of embedding into an image additional information that is not part of the image, the method comprising: dividing a frequency sub-band of the image into a plurality of blocks and providing a block of IWT (integer wavelet transform) coefficients for one of the plurality of blocks; determining a mean value of said coefficients within said block; and establishing an adjusted mean value to embed one of a logical-0 bit value and a logical-1 bit value, corresponding to said additional information, into said block by adjusting multiple coefficient values within a portion of the block that is less than the entire block, according to said logical-0 bit value or said logical-1 bit value, wherein the adjusting multiple coefficient values comprises: removing interference from neighboring IWT-coefficient blocks by applying a mask to said block, and adjusting selected coefficients within said block based on corresponding positions in the mask. 2. The method of claim 1 wherein said establishing comprises: maintaining said mean value unchanged to embed a logical-0 value into said block. 3. The method of claim 1 wherein said establishing comprises: changing said mean value to embed a logical-1 bit value into said block. 4. The method of claim 3 wherein said changing comprises: shifting at least one coefficient of a block in an HL1 sub-band by a shift quantity. 5. The method of claim 4 wherein said changing further comprises: shifting at least one coefficient of an associated block in an LL1 sub-band by about one quarter of said shift quantity. 6. the method of claim 1 further comprising: correcting any erroneous bit arising from said establishing using an error correction code. 7. The method of claim 1 further comprising: identifying a distribution of grayscale values of pixels in a spatial-domain block affected by said IWT coefficients; and customizing said establishing according to said grayscale-value distribution. 8. the method of claim 1 wherein said IWT coefficients comprise: HL1 coefficients. 9. The method according to claim 1, further comprising: dividing IWT coefficients for at least one frequency band of an image into a plurality of non-overlapping blocks and selecting said block of IWT coefficients from among said plurality of non-overlapping blocks; and wherein said establishing an adjusted mean value comprises modifying said mean value to embed one or more bits of data. 10. The method of claim 9 further comprising: identifying at least one coefficient eligible for modification by said modifying and at least one coefficient to remain unchanged during said modifying. 11. The method of claim 9 wherein said modifying said mean value comprises: adding a shift quantity to said mean value. 12. The method of claim 9 wherein said modifying said mean value comprises: subtracting a shift quantity from said mean value. 13. The method of claim 1, wherein the portion of the block is defined by masking the coefficients corresponding to one or more edges of the block. 14. The method of claim 1, wherein establishing the adjusted mean value comprises: selecting a shift value by which to shift the mean value to establish the adjusted mean value. 15. The method of claim 14, wherein said selecting is performed based on a distribution of values of the coefficients of the block. 16. The method of claim 14, further comprising: adjusting at least one coefficient in another frequency sub-band of said image to compensate for an adjustment to at least one of the coefficients of the block. 17. A method, comprising: dividing at least one frequency sub-band of an image into a plurality of blocks and providing a block of IWT (integer wavelet transform) coefficients for one of the plurality of blocks; determining a mean value of said coefficients within said block; establishing an adjusted mean value to embed one of a logical-0 bit value and a logical-1 bit value into said block, wherein said logical-0 or logical-1 bit value corresponds to information extraneous to said image to be embedded into said image, wherein said adjusted mean value is obtained by adjusting multiple coefficient values within a portion of the block that is less than the entire block, according to said logical-0 bit value or said logical-1 bit value; wherein the adjusting multiple coefficient values comprises removing interference from neighboring IWT-coefficient blocks by applying a mask to said block; either transmitting or storing said image, including said first block; obtaining said image; dividing IWT coefficients for at least one frequency band of said image into a plurality of non-overlapping blocks; determining a mean value of coefficients within a first block of said blocks; comparing said mean value to a threshold; and extracting a bit value from said block based on said comparing. 18. An apparatus for embedding into an image additional information that is not part of the image, the apparatus comprising: a dividing means for dividing a frequency sub-band of the image into a plurality of blocks and provide a block of IWT (integer wavelet transform) coefficients for one of the plurality of blocks; a determining means for determining a mean value of said coefficients within said block; and an establishing means for establishing an adjusted mean value to embed one of a logical-0 bit value and a logical-1 bit value, corresponding to said additional information, into said block by adjusting multiple coefficient values within a portion of the block that is less than the entire block, according to said logical-0 bit value or said logical-1 bit value, wherein the establishing means comprises means for removing interference from neighboring IWT-coefficient blocks by applying a mask to said block. 19. An apparatus, comprising: dividing means for dividing at least one frequency sub-band of an image into a plurality of blocks and providing a block of IWT (integer wavelet transform) coefficients for one of the plurality of blocks; determining means for determining a mean value of said coefficients within said block; establishing means for establishing an adjusted mean value to embed one of a logical-0 bit value and a logical-1 bit value into said block, wherein said logical-0 or logical-1 bit value corresponds to information extraneous to said image to be embedded into said image, wherein said adjusted mean value is obtained by adjusting multiple coefficient values within a portion of the block that is less than the entire block, according to said logical-0 bit value or said logical-1 bit value, wherein the establishing means comprises means for removing interference from neighboring IWT-coefficient blocks by applying a mask to said block, wherein the adjusting multiple coefficient values comprises adjusting selected coefficients within said block based on corresponding positions in the mask; means for either transmitting or storing said image, including said first block; obtaining means for obtaining said image; dividing means for dividing IWT coefficients for at least one frequency band of said image into a plurality of non-overlapping blocks; determining means for determining a mean value of coefficients within a first block of said blocks; comparing means for comparing said mean value to a threshold; and extracting means for extracting a bit value from said block based on said comparing.