home *** CD-ROM | disk | FTP | other *** search
/ Developer Source 3 / Developers_Source_Vol_03_1996.iso / dobbs / apr95 / walt1f4.gif < prev    next >
Graphics Interchange Format  |  1996-06-12  |  86.2 KB  |  409x654  |  4-bit (16 colors)
   ocr: (a) - 1 2 3 4 5 Bil J Bito Seal #1 Bit1 Bit2 2. Seal#2 3 Bit3 Bito Bit2 Bit3 4 5 Sample 6x6 - Pixel Image (b) 0 1 2 3 4 5 55 73 71 71 123 123 205 0 120 123 70 72 147 199 - 121 130 123 123 67 68 68 73 123 2 140 133 120 72 70 70 117 3 158 142 123 123 69 71 4 159 122 70 195 178 150 112 67 70 5 714-Original pixel value 70- Pixel value after: embedding a checksum: bit Figure 4: Disguising your checksum as noise using a monocbrome image. (a) Random walk sequence, for Io nontntersecting seals; (b)fixed modijications due to seai embedding (cbecksum-0011,).