NIST Fingerprint Image Quality 2 Documentation

Overview

NIST Fingerprint Image Quality (NFIQ) 2 is open source software that links image quality of optical and ink 500 PPI fingerprints to operational recognition performance. This allows quality values to be tightly defined and then numerically calibrated, which in turn allows for the standardization needed to support a worldwide deployment of fingerprint sensors with universally interpretable image qualities. NFIQ 2 quality features are formally standardized as part of ISO/IEC 29794-4 and serve as the reference implementation of the standard.

Application Programming Interface

This webpage details the application programming interface (API) for NFIQ 2. If you are not a software developer and only need to compute NFIQ 2 quality scores for 500 PPI optical or ink fingerprint images, please navigate to the releases page and download a pre-compiled version of our example application.

Quick Start

Follow these high-level steps to compute an NFIQ 2 quality score in your own application.

1. Include nfiq2.hpp in your source file.
   • NIST's releases install headers in /usr/local/nfiq2/include on macOS and Linux, C:\Program Files\NFIQ 2\include on Windows 64-bit, and C:\Program Files (x86)\NFIQ 2\include on Windows 32-bit.
2. Instantiate a NFIQ2::ModelInfo that points to the included random forest model parameters, and use it to instantiate a NFIQ2::Algorithm.
3. Instantiate a NFIQ2::FingerprintImageData with a decompressed fingerprint image.
4. Pass the NFIQ2::FingerprintImageData from 3 to NFIQ2::Algorithm::computeQualityScore of the NFIQ2::Algorithm instantiated in 2. A quality score is returned or a NFIQ2::Exception is thrown.
   • Note: If the calling application needs to inspect individual quality feature values or quality module calculation speeds, first call NFIQ2::QualityFeatures::computeQualityModules or NFIQ2::QualityFeatures::computeQualityFeatures with the image from 2 instead, and then pass the result of that method to NFIQ2::Algorithm::computeQualityScore. Use the other methods within NFIQ2::QualityFeatures to isolate the individual quality feature values and quality module speeds required.

Examples

Some examples of using the API can be found in the examples directory in the NFIQ 2 repository.

Contact

If you found a bug and can provide steps to reliably reproduce it, or if you have a feature request, please open an issue on GitHub. Other questions may be addressed to the project maintainers by emailing nfiq2.nosp@m.@nis.nosp@m.t.gov.

License

This work is in the public domain. For complete licensing details, refer to LICENSE.md.