Software and method for embedding data in two color images

A computer implemented method of processing a two color image represented as Y(m,n) for watermarking wherein m<M, n<N, said method comprising:

• designating a plurality of pixels at even row and even column coordinates within said two color image as candidate pixels;
• identifying as suitable for storing watermark data by inversion all of said candidate pixels for which,
• one pixel directly above said candidate pixel and one pixel directly below said candidate pixel have different colors;
• and
• one pixel immediately to the left of said candidate pixel and one pixel immediately to the right of said candidate pixel have different colors, by
• forming a two dimensional array HLoo(i−1,j−1)=Y(2i−1, 2j)⊕Y(2i, 2j), having one entry for each of said candidate pixels;
• forming a two dimensional array HLeo(i,j−1)=Y(2i, 2j)⊕Y(2i1, 2j), having one entry for each of said candidate pixels;
• forming a two dimensional array LHoo(i−1,j−1)=Y(2i, 2j−1)⊕Y(2i, 2j), having one entry for each of said candidate pixels;
• forming a two dimensional array LHoe(i−1,j)=Y(2i, 2j)⊕Y(2i, 2j1), having one entry for each of said candidate pixels;
• assessing values of (i,j) for which (HLoo(i−1, j−1)⊕HLeo(i, j−1))^(LHoo(i−1, j−1)⊕LHoe(i−1, j))=1 to identify invertible candidate pixels at locations (2i, 2j) in said image, wherein i, j, m, n, M, N are positive integers, greater than zero, and 2i+1<M, 2j+1<N.

A computer implemented method of processing a two color image represented as Y(m,n) for watermarking wherein m<M, n<N, said method comprising:

• designating a plurality of pixels at even row and even column coordinates within said two color image as candidate pixels:
• identifying as suitable for storing watermark data by inversion all of said candidate pixels for which,
• one pixel directly above said candidate pixel and one pixel directly below said candidate pixel have different colors;
• and
• one pixel immediately to the left of said candidate pixel and one pixel immediately to the right of said candidate pixel have different colors, by
• forming a two dimensional array
• HLL ee(i, j)=Y(2i−1,2j)⊕Y(2i+1,2j), having one entry for each of said candidate pixels;
• forming a two dimensional array
• LHL ee(i, j)=Y(2i,2 j−1)⊕Y(2i,2 j+1), having one entry for each of said candidate pixels;
• assessing values of (i,j) for which HLLee(i, j)⊕LHLee(i, j)=1 to identify invertible pixels at locations (2i, 2j) in said image, wherein i, j, m, n, M, N are non-zero positive integers and 2i+1<M, 2j+1<N.

A computer implemented method of processing a two color image represented as Y(m,n) for watermarking wherein m<M, n<N, said method comprising:

• designating a plurality of pixels at odd row and odd column coordinates within said two color image as candidate pixels;
• identifying as suitable for storing watermark data by inversion all of said candidate pixels for which,
• one pixel directly above said candidate pixel and one pixel directly below said candidate pixel have different colors;
• and
• one pixel immediately to the left of said candidate pixel and one pixel immediately to the right of said candidate pixel have different colors, by
• forming a two dimensional array
• LHL OO(i, j)=Y(2i+1,2j)⊕Y(2i+1,2j)+2), having one entry for each of
• said candidate pixels;
• forming a two dimensional array
• HLL OO(i, j)=Y(2i,2j+1)⊕Y(2i+2,2j+1), having one entry for each of
• said candidate pixels;
• assessing values of (i,j) for which HLLOO(i, j)⊕LHLOO(i, j)=1 to identify invertible candidate pixels at locations (2i+1, 2j+1) in said image, wherein 1, 1, m, n, M, N are integers and 2i+2<M, 2j+2<N.

A computer implemented method of processing a two color image represented as Y(m,n) for watermarking wherein m<M, n<N, said method comprising:

• designating a plurality of pixels at odd row and odd column coordinates, and at even row and even column coordinates within said two color image as candidate pixels;
• identifying as suitable for storing watermark data by inversion all of said candidate pixels for which,
• one pixel directly above said candidate pixel and one pixel directly below said candidate pixel have different colors, and
• one pixel immediately to the left of said candidate pixel and one pixel immediately to the right of said candidate pixel have different colors, by forming a two dimensional array
• HLL ee(i, j)=Y(2i−1,2j)⊕Y(2i+1,2j), having one entry for each of said candidate pixels;
• forming a two dimensional array
• LHL ee(i, j)=Y(2i,2 j−1)⊕Y(2i,2j+1), having one entry for each of said candidate pixels;
• forming a two dimensional array
• LHL OO (i, j)=Y(2i+1,2+j)⊕Y(2i+1,2j+2), having one entry for each of said candidate pixels;
• forming a two dimensional array
• HLL OO (i, j)=Y(2i,2j+1)⊕Y(2i+2,2j+1), having one entry for each of said candidate pixels;
• assessing values of (i,j) for which HLLOO(i, j)⊕LHLOO(i, j)=1;
• or
• HLLee(i, j)⊕LHLee(i, j)=1 to identify candidate pixels at locations (2i, 2j) and (2i+1, 2j+1) within said image that are invertible, wherein i, j, m, n, M, N are non-zero, positive integers and 2i+2<M, 2j+2<N.

A computer implemented method of processing a two color image represented as Y(m,n) for watermarking wherein m<M, n<N, said method comprising:

• designating a plurality of pixels at odd row and even column coordinates within said two color image as candidate pixels;
• identifying as suitable for storing watermark data by inversion all of said candidate pixels for which,
• one pixel directly above said candidate pixel and one pixel directly below said candidate pixel have different colors, and
• one pixel immediately to the left of said candidate pixel and one pixel immediately to the right of said candidate pixel have different colors, by
• forming a two dimensional array
• HLLeo(i, j)=Y(2i−1,2j+1)⊕Y(2i+1,2j+1), having one entry for each of said candidate pixels;
• forming a two dimensional array LHLeo(i, j)=Y(2i,2j)⊕Y(2i,2 j+2), having one entry for each of said candidate pixels;
• assessing values of (i,j) for which HLLeo(i, j)⊕LHLeo (i, j)=1 to identify invertable pixels at locations (2i, 2j+1) in said image, wherein i, j, m, n, M, N are non-negative integers and 2k<M, 2j+2<N.

A computer implemented method of processing a two color image represented as Y(m,n) for watermarking wherein m<M, n<N, said method comprising:

• designating a plurality of pixels at even row and odd column coordinates within said two color image as candidate pixels:
• identifying as suitable for storing watermark data by inversion all of said candidate pixels for which,
• one pixel directly above said candidate pixel and one pixel directly below said candidate pixel have different colors, and
• one pixel immediately to the left of said candidate pixel and one pixel immediately to the right of said candidate pixel have different colors, by
• forming a two dimensional array
• LHLoe(i, j)=(Y(2i+1,2j−1)⊕Y(2i+1,2j+1)), having one entry for each of
• said candidate pixels;
• forming a two dimensional array
• HLLoe(i, j)=(Y(2i,2j)⊕Y(2i+2,2j)), having one entry for each of said candidate pixels;
• assessing values of (i,j) for which HLLoe(i, j)⊕LHLoe(i, j)=1 to assess if candidate pixels at locations (2i+1, 2j) are invertible, wherein i, j, m, n, M, N are non-negative integers and 2i+1<M, 2j+1<N.

A computer implemented method of processing a two color image represented as Y(m,n) for watermarking wherein m<M, n<N, said method comprising:

• designating a plurality of pixels at odd row and even column coordinates, and at even row and odd column coordinates within said two color image as candidate pixels;
• identifying as suitable for storing watermark data by inversion all of said candidate pixels for which,
• one pixel directly above said candidate pixel and one pixel directly below said candidate pixel have different colors, and
• one pixel immediately to the left of said candidate pixel and one pixel immediately to the right of said candidate pixel have different colors, by
• forming a two dimensional array
• LHLoe(i, j)=(Y(2i+1,2j−1)⊕Y(2i+1,2j+1)), having one entry for each of said candidate pixels;
• forming a two dimensional array
• HLLoe(i, j)=(Y(2i,2j)⊕Y(2i+2,2j)), having one entry for each of said candidate pixels;
• forming a two dimensional array
• HLLeo(i, j)=Y(2i−1,2j+1)⊕Y(2i+1,2j+1), having one entry for each of said candidate pixels;
• forming a two dimensional array LHLeo(i, j)=Y(2i,2j)⊕Y(2i,2j+2), having one entry for each of said candidate pixels;
• assessing values of (i,j) for which HLLeo(i, j)⊕LHLeo(i, j)=1 or for
• for which HLLoe(i, j)⊕(i, j)=1 to assess if pixels at locations (2i, 2j+1) and (2i+1, 2j) in said image may be inverted, wherein i, j, m, n, M, N are positive, non-zero integers and 2i+2<M, 2j+2<N.