WSQ file - Compression

Question

I received a sample with 1.000 fingerprints (WSQ files - 100 people with 10 fingerprints each) in WSQ format.

I know that WSQ is a compressed format. My question is: Is there a way to compress this again?

The compression algorithm should find patterns between fingerprints file.

Thanks a lot!

Answer 1

This is quite unlikely.

The compression algorithm applied directly on SWQ files may find some repetitions in the file structure, most likely in the header. This will provide maybe a few % of gains, but no more.

In any case, you can't be wrong with testing this hypothesis by using a simple compression program in "solid" mode, such as 7zip.

Answer 2

Yes, a reference implementation of a WSQ encoder (and decoder) is provided in the NBIS package:

http://www.nist.gov/itl/iad/ig/nbis.cfm