WSQ Fingerprint Image Compression
Encoder/Decoder
Certification Guidelines
April 28, 2009

Introduction

The Wavelet Scalar Quantization (WSQ) Gray-scale Fingerprint Image Compression Algorithm is the standard for the exchange of 8-bit, 500ppi fingerprint images within the criminal justice community. This document describes the processes and procedure for obtaining FBI certification of WSQ implementations for compliance with the WSQ Specification. This certification program will facilitate interoperability between agencies and ensure efficient access to FBI criminal justice information services.

Scope

The WSQ Specification defines a class of encoders and a single decoder with sufficient generality to decode compressed image data produced by any compliant encoder. This provides an opportunity for future enhancement in key areas while maintaining compatibility with an installed base of equipment. To obtain certification, a WSQ decoder must implement the full range of functionality contained in the WSQ Specification, Part I: Requirements and Guidelines. This includes the ability to reconstruct images using even and odd length filters and imbedded restart codes. Part III of the WSQ specification contains the specific parameter values that must be implemented by encoders for certification.

Compliance with the WSQ Specification is determined by comparing the output from the implementation under test with the output from a double precision reference implementation developed at the National Institute of Standards and Technology (NIST). The comparison criteria and accuracy requirements are contained in the WSQ Specification, Annex AA: Procedures for Determining Compliance.

Certification Procedure

The vendor using the reference test set created from the NIST reference implementation conducts initial certification testing. This self-test procedure enables a vendor to react quickly to technology advancements and market requirements without being constrained by the FBI's limited personnel resources.

The reference test set can be downloaded from NIST via the Internet:

     ftp://sequoyah.nist.gov/pub/cmp_imgs/cmp_imgs/

NEW Once the vendor has determined that their software meets all the requirements in the WSQ Specification, FBI WSQ software implementation numbers (one for each platform to be submitted) must be obtained from:

     Stan Janet
     sjanet@nist.gov

The encoder test set contains 19 raw-format images, each of which must compressed at two different bit rates, producing 38 separate tests for the encoder. For each test, the encoder under test must match the file size, the parameter values in the header, and the quantized wavelet coefficient bin index values of the reference data within the accuracy requirements contained in the WSQ Specification.

The decoder test set contains 17 WSQ-format images compressed at the two different bit rates above, as well as 6 more images compressed with parameter values other then those given in Part III of the WSQ Specification. These additional tests evaluate the decoder's functionality on the full range of parameter values given in Part I of the WSQ Specification. For each of these 40 tests, the reference-compressed image is reconstructed using the decoder under test and the result compared to the reference reconstruction.

Take care to not overwrite the WSQ-format images in the decoder test set with the WSQ-format images you produce in the encoder test.

NIST should then be given the vendor's compressed raw-format images (.wsq file extension) and the reconstructed WSQ-format images (.rec file extension). The fastest and easiest way to do that is to put the files in a tar or zip archive and place that on a website (or FTP site) for NIST to download. The other way to do that is to burned the files to a CD-R or DVD-R and mail the disc to:

      Stan Janet - WSQ Certification Liaison
      NIST
      100 Bureau Drive, Mailstop 8940
      Gaithersburg, MD 20899
      USA

After processing the appropriate files for the encoder and decoder, a certification request containing the test report, test results, and all generated compressed and reconstructed files (cmp000xx with extensions '.wsq' and '.rec') are forwarded to the FBI for review and evaluation.

The FBI may request additional information or conduct supplemental tests to determine full compliance with the WSQ Specification.

If all the required information is complete and the results are satisfactory, the FBI CJIS Division will issue a letter certifying that the implementation is compliant with the WSQ Specification. That implementation number and description will than be added to the current list of approved implementations maintained by the FBI.

The FBI certification for an implementation will apply only to a specific configuration. A configuration encompasses the software version of the encoder/decoder, hardware platform, operating system, and compiler used. As any of these components change, a recertification will be required.

Downloading the Reference Test Set

The reference test files are available on the Internet at the NIST FTP site sequoyah.nist.gov. The easiest way to download the files is to use an Internet file downloading program, such as "wget":

     wget -r -c -nH --cut-dirs=2 ftp://anonymous:you%40youremail.com@sequoyah.nist.gov/pub/cmp_imgs/cmp_imgs

The files can also be downloaded using the regular "ftp" program:

     - "ftp" to sequoyah.nist.gov; use "anonymous" as
       the login name and your email address as the password.
     - Change to directory pub/cmp_imgs:
		cd pub/cmp_imgs/cmp_imgs
     - Set non-prompting mode:
		prompt
     - Set transfer mode to binary:
		binary
     - Enable "passive mode" for transfers (may not be required -- it
       depends on the traffic allowed by any firewall you might have):
		passive
     - Transfer all the original image files from this directory:
		mget *.raw
     - Use similar commands to transfer the rest of the files
     - Close the FTP connection:
		quit

The README file provides additional documentation and the DIRECTRY file, listed below, provides a complete listing of all files.

total 8740
drwxr-xr-x 2 root	4096 Jun 28 08:06 225
drwxr-xr-x 2 root	4096 Jun 28 08:09 75
-rw-r--r-- 1 root	814 May 10 13:38 CHANGES
-rw-r--r-- 1 root	0 Jun 28 08:19 DIRECTRY
-rw-r--r-- 1 root	2698 May 10 13:26 README
-rw-r--r-- 1 root	356345 Apr 4 08:59 cmp0000l.raw
-rw-r--r-- 1 root	638976 Apr 4 08:59 cmp00002.raw
-rw-r--r-- 1 root	638976 Apr 4 08:59 cmp00003.raw
-rw-r--r-- 1 root	612880 Apr 4 08:59 cmp00004.raw
-rw-r--r-- 1 root	638976 Apr 4 08:59 cmp00005.raw
-rw-r--r-- 1 root	638976 Apr 4 08:59 cmp00006.raw
-rw-r--r-- 1 root	347710 Apr 4 08:59 cmp00007.raw
-rw-r--r-- 1 root	600000 Apr 4 08:59 cmp00008.raw
-rw-r--r-- 1 root	347136 Apr 4 08:59 cmp00009.raw
-rw-r--r-- 1 root	197250 Apr 4 08:59 cmp000l0.raw
-rw-r--r-- 1 root	440238 Apr 4 08:59 cmp000ll.raw
-rw-r--r-- 1 root	369456 Apr 4 08:59 cmp000I2.raw
-rw-r--r-- 1 root	350889 Apr 4 08:59 cmp000l3.raw
-rw-r--r-- 1 root	269348 Apr 4 08:59 cmp000l4.raw
-rw-r--r-- 1 root	292120 Apr 4 08:59 cmp000l5.raw
-rw-r--r-- 1 root	504828 Apr 4 08:59 cmp000l6.raw
-rw-r--r-- 1 root	346986 Apr 4 08:59 cmp000l7.raw
-rw-r--r-- 1 root	562500 Apr 4 08:59 cmp000l8.raw
-rw-r--r-- 1 root	562500 Apr 4 08:59 cmp000l9.raw
drwxr-xr-x 2 root	8192 Jun 28 08:l1 not_7_ 9

All compressed and reconstructed files are in the subdirectories 75, 225, and not_7_9.

Created July 8, 1999.
Last modified April 28, 2009.
Contact webmaster@magi.nist.gov with corrections/comments.