Relative contrast mask

Relative contrast mask, a part of algorithm transparency, is a set of primary blocks on the block map where contrast is too low relative to other parts of the image. It is computed during feature extraction. Relative contrast mask contributes to combined mask.

KeywordSuffixZip
relative-contrast-mask.json014-relative-contrast-mask.json
relative-contrast-mask.dat015-relative-contrast-mask.dat

Visualization

Relative contrast visualization can be computed from this stage's binary data combined with block map and original fingerprint image. Visualization itself is not part of transparency data.

Relative contrast mask visualized as yellow masked out area around fingerprint image
Relative contrast mask. Yellow area consists of blocks excluded due to low contrast.

Binary data

Binary data has the same format as for absolute contrast mask.

Example: 015-relative-contrast-mask.dat

Json

Json data describes basic properties of the binary data, most importantly dimensions of the mask, which is the same as the number of primary blocks.

Example: 014-relative-contrast-mask.json

{
  "axes": [
    "y",
    "x"
  ],
  "dimensions": [
    25,
    26
  ],
  "scalar": "boolean",
  "bitness": 8,
  "format": "false as 0, true as 1"
}