> For the complete documentation index, see [llms.txt](https://docs.griaule.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.griaule.com/gbs/en/overview/biometricevaluation.md).

# Biometric Quality Assessment

This manual has the purpose of describing the parameters considered for the evaluation of the quality of a biometric extraction.

The quality evaluation is done during the process of extracting a template. This process aims to determine which are the best images to be used in biometric comparison procedures.

Each biometric modality has its various evaluation criteria. Below, the criteria for evaluating face and fingerprint images will be addressed.

## Fingerprint Evaluation

The list of parameters evaluated for a fingerprint image is the following:

> * Image size;
> * Number of minutiae;
> * Number of high-reliability minutiae;
> * Number of minutiae above the interphalangeal fold;
> * Contrast;
> * Finger orientation;
> * Loss of fingerprint section (edge cut by the reader);
> * Finger area;
> * Finger extension;
> * Value according to the NFIQ standard.

## Face Image Evaluation

The list of parameters evaluated for a face image is the following:

> * Size;
> * Number of faces detected in the image;
> * Eye position;
> * Face shape match with the ICAO standard;
> * Background uniformity;
> * Image sharpness;
> * Gray level;
> * Face orientation;
> * Face rotation;
> * Open mouth or smile;
> * Obstructions on the face;
> * Background color.


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