NIST Special Database 27A

The tool described on this page can be used to upload the NIST SD-27A database into PiAnoS.

Background information

The NIST SD-27A is a reference collection of marks and prints. From the website:

NIST Special Database 27A - The National Institute of Standards and Technology in conjunction with the Federal Bureau of Investigation has maintained a database of grayscale fingerprint images, corresponding minutiae and selected latent fingerprints corresponding to fingerprint images in the data set. This data set is known as Special Database 27 (SD-27) and provides 500ppi imagery. In 2010, this data set was expanded to provide 1000ppi imagery to the research community and has been made available for electronic distribution. This data set is herein referred to as SD-27A.

Downloads and information can be found at http://www.nist.gov/itl/iad/ig/sd27a.cfm.

The provided tool creates a folder in PiAnoS that contains all matching pairs (latent vs. corresponding reference print), each one as a separate exercise.

Note that the tool performs automatic conversions from JPEG 2000 to PNG, because PiAnoS does not natively handle JP2 images.

Prerequisites

Usage

The script takes two mandatory arguments:

  • the path to the directory were SD-27A was unpacked. This directory should contain the file Readme.txt and the two directories: 500ppi-Legacy and 1000ppi.

  • the “pgsql URL” to the database. It is a convenient way to specify all of database name, host, port, username, and password in a single argument, using the syntax “pgsql://username:password@host:port/dbname”.

Since the dataset contains many marks and prints, there is a huge number of mark-print combinations that can be used as exercises in PiAnoS. import_nist_sd27.py has several modes to select how these marks and prints are combined. Note that not all marks have a corresponding print, that many marks have two corresponding prints, and many prints do not have a corresponding mark.

Mode

Description

1

Default mode. For each mark that has at least one corresponding print, an exercise is created. Marks that have more than one print only appear once, with the first matching print.

2

Like mode 1, but additionnal exercises are created for all prints of a mark (thus, the same mark can appear multiple times). This is a superset of mode 1.

Additionnal parameters:

  • --mode: see table above.

  • --dry-run: to check how many exercises would be created - this does not modify the database in any way.

  • --folder: to set the name of the PiAnoS folder

Examples

Getting extended usage information on Linux:

$ python import_nist_sd27.py --help

On Linux, assuming SD27A has been upacked to /home/bob/sd27a, and using a database named pianos on localhost, with username uname and password pwd, using the default mode:

$ python import_nist_sd27.py /home/bob/sd27a pgsql://uname:pwd@localhost/pianos

On Windows, assuming SD27A has been unpacked to C:\Users\Bob\sd27a, and using a database named pianos on the remote server pianos-srv, with username pianos and password passwd, using mode 2:

import_nist_sd27.py -m 2 "C:\Users\Bob\sd27a" pgsql://pianos:passwd@pianos-srv/pianos