Filtered mask
Filtered mask, a part of algorithm transparency, refines combined mask using a set of filters into a mask marking valid fingerprint area. It is computed during feature extraction. It is used to derive equalized image, block orientation and smoothed orientation, parallel smoothing and orthogonal smoothing, and binarized image and derived data. It is later processed into pixel mask and subsequently into inner mask.
Key | MIME | Filename in ZIP |
---|---|---|
filtered-mask | application/cbor | 011-filtered-mask.cbor |
Visualization
Mask visualization can be computed from this stage's binary data mapped onto blocks and the original fingerprint image. Visualization itself is not part of transparency data.
Format
Filtered mask has the same format as absolute contrast mask
except that true
marks high-contrast (interior) blocks while false
marks low-contrast (exterior) blocks.
Example: 011-filtered-mask.cbor
{ "width": 26, "height": 25, "cells": [ false, false, "... skipped 646 items ...", false, false ] }