Skeleton minutiae in SourceAFIS transparency data

SourceAFIS » Algorithm » Transparency » Skeleton minutiae

Skeleton minutiae, a part of algorithm transparency, are minutiae obtained directly from ridge and valley skeletons during feature extraction, specifically from the last filtering stage of both skeletons. Only skeleton minutiae with exactly one connected ridge (or valley) are considered. Skeleton minutiae from ridge skeleton become endings. Skeleton minutiae from valley skeleton become bifurcations. Skeleton minutiae are subsequently filtered to inner minutiae, have minutia clouds removed, pass through top minutiae filter, and lastly get shuffled before being used to construct edge table.

KeyMIMEFilename in ZIP
skeleton-minutiaeapplication/cbor038-skeleton-minutiae.cbor

Visualization

Visualization of skeleton minutiae was constructed from this stage's CBOR data with original fingerprint in the background. Visualization itself is not part of transparency data.

Fingerprint minutiae, blue endings and green bifurcations, collected from skeletons with original fingerprint in the background
Minutiae collected from ridge and valley skeletons. Endings are blue, bifurcations are green.

Format

Minutiae are reported as part of an intermediate fingerprint template format only used in algorithm transparency. The intermediate template is a CBOR-encoded data structure:

Every minutia has the following fields:

Example: 038-skeleton-minutiae.cbor

{
  "size": {
    "x": 388,
    "y": 374
  },
  "minutiae": [
    {
      "position": {
        "x": 76,
        "y": 268
      },
      "direction": 5.472151735260461,
      "type": "ENDING"
    },
    {
      "position": {
        "x": 80,
        "y": 156
      },
      "direction": 1.9936502529278375,
      "type": "ENDING"
    },
    "... skipped 111 items ...",
    {
      "position": {
        "x": 310,
        "y": 166
      },
      "direction": 4.607512041654456,
      "type": "BIFURCATION"
    },
    {
      "position": {
        "x": 214,
        "y": 74
      },
      "direction": 0.844153986113171,
      "type": "BIFURCATION"
    }
  ]
}