Documentation Index
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The constants defined in nfiq2_constants.hpp provide standardized identifiers for quality measures, algorithms, CBEFF identifiers, actionable feedback, and threshold values used throughout NFIQ2.
Identifiers Namespace
The NFIQ2::Identifiers namespace contains identification strings for various objects used in NFIQ2.
CBEFF Quality Algorithm Identifiers
CBEFF (Common Biometric Exchange Formats Framework) quality algorithm identifiers.
namespace NFIQ2::Identifiers::CBEFF
| Constant | Type | Description |
|---|
Vendor | unsigned int | Quality algorithm vendor identifier |
NFIQ2Rev0 | unsigned int | Unified quality score (NFIQ 2.0) |
NFIQ2Rev1 | unsigned int | Unified quality score (NFIQ 2.1) |
NFIQ2Rev2 | unsigned int | Unified quality score (NFIQ 2.2) |
NFIQ2Rev3 | unsigned int | Unified quality score (NFIQ 2.3) |
Orientation Certainty
namespace NFIQ2::Identifiers::CBEFF::OrientationCertainty
| Constant | Type | Description |
|---|
Mean | unsigned int | Mean of local orientation certainty level |
StdDev | unsigned int | Standard deviation of local orientation certainty level |
Local Clarity
namespace NFIQ2::Identifiers::CBEFF::LocalClarity
| Constant | Type | Description |
|---|
Mean | unsigned int | Mean of local clarity score |
StdDev | unsigned int | Standard deviation of local clarity score |
Frequency Domain Analysis
namespace NFIQ2::Identifiers::CBEFF::FrequencyDomainAnalysis
| Constant | Type | Description |
|---|
Mean | unsigned int | Mean of local frequency domain analysis |
StdDev | unsigned int | Standard deviation of local frequency domain analysis |
namespace NFIQ2::Identifiers::CBEFF::RidgeValleyUniformity
| Constant | Type | Description |
|---|
Mean | unsigned int | Mean of local ridge valley uniformity |
StdDev | unsigned int | Standard deviation of local ridge valley uniformity |
Orientation Flow
namespace NFIQ2::Identifiers::CBEFF::OrientationFlow
| Constant | Type | Description |
|---|
Mean | unsigned int | Mean of local orientation flow |
StdDev | unsigned int | Standard deviation of orientation flow |
Contrast
namespace NFIQ2::Identifiers::CBEFF::Contrast
| Constant | Type | Description |
|---|
ImageMean | unsigned int | Average contrast (“MU”) |
MeanOfBlockMeans | unsigned int | Average of average contrasts (“MMB”) |
Minutiae
namespace NFIQ2::Identifiers::CBEFF::Minutiae
| Constant | Type | Description |
|---|
Count | unsigned int | Minutiae count |
CountCOM | unsigned int | Minutiae count in center of mass |
PercentImageMean50 | unsigned int | Minutiae quality based on image mean |
PercentOrientationCertainty80 | unsigned int | Minutiae quality based on orientation certainty level |
Region of Interest
namespace NFIQ2::Identifiers::CBEFF::RegionOfInterest
| Constant | Type | Description |
|---|
Mean | unsigned int | Region of interest image mean |
OrientationMapCoherenceSum | unsigned int | Region of interest orientation map coherence sum |
OrientationMapCoherenceMean | unsigned int | Region of interest relative orientation map coherence sum |
Actionable Quality Feedback
Identifiers for interpretation of quality measures that may indicate corrective measures for subsequent captures.
namespace NFIQ2::Identifiers::ActionableQualityFeedback
| Constant | Type | Description |
|---|
EmptyImageOrContrastTooLow | const char[] | The image is blank or the contrast is too low (mean gray level appears white) |
UniformImage | const char[] | Standard deviation of gray levels in image indicates uniformity |
FingerprintImageWithMinutiae | const char[] | Number of minutia in image |
SufficientFingerprintForeground | const char[] | Number of pixels in the computed foreground |
Unified Quality Scores
Combinations of all quality measures via a pattern classifier.
namespace NFIQ2::Identifiers::UnifiedQualityScores
| Constant | Type | Description |
|---|
NFIQ2Rev0 | const char[] | Unified quality score (NFIQ 2.0) |
NFIQ2Rev1 | const char[] | Unified quality score (NFIQ 2.1) |
NFIQ2Rev2 | const char[] | Unified quality score (NFIQ 2.2) |
NFIQ2Rev3 | const char[] | Unified quality score (NFIQ 2.3) |
Prediction Algorithms
Algorithms that combine quality measures to compute a unified quality score.
namespace NFIQ2::Identifiers::PredictionAlgorithms
| Constant | Type | Description |
|---|
RandomForest | const char[] | Identifier for the RandomForest prediction algorithm |
Quality Measure Algorithms
Algorithms that compute one or more quality measures.
namespace NFIQ2::Identifiers::QualityMeasureAlgorithms
| Constant | Type | Description |
|---|
FrequencyDomainAnalysis | const char[] | Identifier for the FrequencyDomainAnalysis quality measure algorithm |
MinutiaeCount | const char[] | Identifier for the MinutiaeCount quality measure algorithm |
MinutiaeQuality | const char[] | Identifier for the MinutiaeQuality quality measure algorithm |
LocalClarity | const char[] | Identifier for the LocalClarity quality measure algorithm |
Contrast | const char[] | Identifier for the Contrast quality measure algorithm |
OrientationCertainty | const char[] | Identifier for the OrientationCertainty quality measure algorithm |
OrientationFlow | const char[] | Identifier for the OrientationFlow quality measure algorithm |
RegionOfInterestMean | const char[] | Identifier for the RegionOfInterestMean quality measure algorithm |
RegionOfInterestCoherence | const char[] | Identifier for the RegionOfInterestCoherence quality measure algorithm |
RidgeValleyUniformity | const char[] | Identifier for the RidgeValleyUniformity quality measure algorithm |
Quality Measures
Identifiers of individual quality measures.
namespace NFIQ2::Identifiers::QualityMeasures
Frequency Domain Analysis
Frequency of the sinusoid following the ridge-valley structure.
namespace NFIQ2::Identifiers::QualityMeasures::FrequencyDomainAnalysis
| Constant | Type | Description |
|---|
Mean | const char[] | Mean of local quality value |
StdDev | const char[] | Standard deviation of local quality values |
Histogram::Bin0 - Histogram::Bin9 | const char[] | Local quality values represented as histogram bins (10 bins total) |
Minutiae
Measures relative to minutiae detected using FingerJet FX OSE.
namespace NFIQ2::Identifiers::QualityMeasures::Minutiae
| Constant | Type | Description |
|---|
Count | const char[] | Number of minutiae in the image |
CountCOM | const char[] | Number of minutiae in a 200x200 pixel rectangle centered at center of mass |
PercentImageMean50 | const char[] | Percentage of minutiae with quality value (Contrast::Mean) between 0-0.5 |
PercentOrientationCertainty80 | const char[] | Percentage of minutiae with Orientation Certainty Level above 80 |
Region of Interest
Measures based on the foreground area of the image.
namespace NFIQ2::Identifiers::QualityMeasures::RegionOfInterest
| Constant | Type | Description |
|---|
Mean | const char[] | Mean grayscale value of local regions with at least 1 pixel in the ROI |
CoherenceSum | const char[] | Sum of coherence values over all local regions within the ROI |
CoherenceMean | const char[] | Average of coherence values over all local regions within the ROI |
Local Clarity
Measure of the clarity of ridges and valleys.
namespace NFIQ2::Identifiers::QualityMeasures::LocalClarity
| Constant | Type | Description |
|---|
Mean | const char[] | Mean of local quality value |
StdDev | const char[] | Standard deviation of local quality values |
Histogram::Bin0 - Histogram::Bin9 | const char[] | Local quality values represented as histogram bins (10 bins total) |
Contrast
Measure of the gray levels of the image.
namespace NFIQ2::Identifiers::QualityMeasures::Contrast
| Constant | Type | Description |
|---|
ImageMean | const char[] | Arithmetic mean of the image |
MeanOfBlockMeans | const char[] | Arithmetic mean of per-block means of the image |
Orientation Certainty
Measure of the strength of energy concentration along dominant ridge flow orientation.
namespace NFIQ2::Identifiers::QualityMeasures::OrientationCertainty
| Constant | Type | Description |
|---|
Mean | const char[] | Mean of local quality value |
StdDev | const char[] | Standard deviation of local quality values |
Histogram::Bin0 - Histogram::Bin9 | const char[] | Local quality values represented as histogram bins (10 bins total) |
Orientation Flow
Measure of ridge flow continuity based on absolute orientation difference.
namespace NFIQ2::Identifiers::QualityMeasures::OrientationFlow
| Constant | Type | Description |
|---|
Mean | const char[] | Mean of local quality value |
StdDev | const char[] | Standard deviation of local quality values |
Histogram::Bin0 - Histogram::Bin9 | const char[] | Local quality values represented as histogram bins (10 bins total) |
namespace NFIQ2::Identifiers::QualityMeasures::RidgeValleyUniformity
| Constant | Type | Description |
|---|
Mean | const char[] | Mean of local quality value |
StdDev | const char[] | Standard deviation of local quality values |
Histogram::Bin0 - Histogram::Bin9 | const char[] | Local quality values represented as histogram bins (10 bins total) |
Thresholds Namespace
Threshold constants for actionable quality feedback.
namespace NFIQ2::Thresholds::ActionableQualityFeedback
Identifiers::ActionableQualityFeedback with these thresholds may indicate corrective actions for subsequent captures.
| Constant | Type | Description |
|---|
EmptyImageOrContrastTooLow | double | Threshold for empty image or contrast too low detection |
UniformImage | double | Threshold for uniform image detection |
FingerprintImageWithMinutiae | double | Threshold for minutiae presence |
SufficientFingerprintForeground | double | Threshold for foreground sufficiency |
Sizes Namespace
Block size constants used in quality measure calculations.
| Constant | Type | Value | Description |
|---|
LocalRegionSquare | unsigned int | 32 | Pixels (width and height) comprising a local region per ISO/IEC 29794-4:202X |
VerticallyAlignedLocalRegionWidth | unsigned int | 32 | Width after rotating local region to vertically align ridges |
VerticallyAlignedLocalRegionHeight | unsigned int | 16 | Height after rotating local region to vertically align ridges |
Source Reference
Defined in: NFIQ2/NFIQ2Algorithm/include/nfiq2_constants.hpp