December 29, 2017

# Tutorial: Optimize fingerprint minutiae quality

### Introduction

This tutorial continues from the previous one which is on Using NIST Fingerprint software to generate a pairwise comparison score matrix. So, do read this before doing this one.

In this tutorial, you will learn how to optimize the fingerprint minutiae quality threshold. The Detection Error Trade-off (DET) curve before and after using a better threshold is shown below.

As can be observed, there is a marked improvement by simplying using only minutiae of sufficiently high quality.

### Procedures

##### 2. Create a new copy of the features directory which contains fingerprint templates with only sufficiently high quality minutiae.

Let’s take a look at an xyt file using head features_original/100_1.xyt in bash, which gives the following output:

The first column shows the row and column of minutiae and the third column shows the orientation. The last column is what we are interested in; it shows the quality of the minuatiae. The code below will filter out the minutiae with low quality by using a threshold of 20 and then writing the feature files back to the features directory.

##### 4. Analyse the scores

First, we load the scores produced in the previous tutorial; and call it scores.

Next, we get the genuine and impostor scores, reusing the variable user created in the previous tutorial.