Inner mask

Inner mask, a part of algorithm transparency, is computed during feature extraction by shrinking pixel mask. It represents inner fingerprint area, somewhat away from fingerprint border. It is used for inner minutiae filtering.

KeywordSuffixZip
inner-mask.json038-inner-mask.json
inner-mask.dat039-inner-mask.dat

Visualization

The following visualization was created from this stage's binary data overlaid on top of the original fingerprint image. Visualization itself is not part of transparency data.

Fingerprint image with interior area highlighted in yellow color
Inner mask region is shown as light yellow.

Binary data

Binary data has the same structure as for pixel mask except that value 1 now marks the inner mask.

Example: 039-inner-mask.dat

Json

Json data describes basic properties of the binary data, most importantly dimensions of the image.

Example: 038-inner-mask.json

{
  "axes": [
    "y",
    "x"
  ],
  "dimensions": [
    374,
    388
  ],
  "scalar": "boolean",
  "bitness": 8,
  "format": "false as 0, true as 1"
}