Wavelet Scalar Quantization
The Wavelet Scalar Quantization algorithm (WSQ) is a compression algorithm used for gray-scale fingerprint images. It is based on wavelet theory and has become a standard for the exchange and storage of fingerprint images. WSQ was developed by the FBI, the Los Alamos National Laboratory, and the National Institute of Standards and Technology (NIST).
This compression method is preferred over standard compression algorithms like JPEG because at the same compression ratios WSQ doesn't present the "blocking artifacts" and loss of fine-scale features that are not acceptable for identification in financial environments and criminal justice. 
- WSQ Fingerprint Image Compression Encoder/Decoder Certification Guidelines
- Aware WSQ1000 SDK
- Net-X Solutions WSQ SDK
- Jain, Anil; Pankanti, Sharath (2001). "Automated Fingerprint Identification and Imaging Systems". Advances in Fingerprint Technology (2nd ed.). CRC Press. pp. 275–326. ISBN 978-0-8493-0923-6.