WSQ Fingerprint Image Compression Encoder/Decoder Certification


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. Listed below are all the FBI certified WSQ implementations for compliance with the WSQ Specification. This certification program facilitates interoperability between agencies and ensures efficient access to FBI criminal justice information services.


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 embedded 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).

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.

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

Note: 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.

Also note that the certification process is not intended to endorse one product over a competitor's product, but merely to certify that the product meets FBI standards and that, between two products that meet FBI standards, the FBI does not recommend one over the other.

WSQ Certified Algorithms