After lot 713, Microsoft fingerprint readers changed. The new version
comes with a new USB product ID and a challenge-response authentication
scheme where the device challenges the authenticity of the driver.
An independent third party produced documentation on the computations
needed to convert a challenge into the correct response, and I then used
this documentation to produce a clean-room reimplementation of the
authentication scheme.
mindtct appears to completely ignore the pixels-per-mm input parameter
(ippmm). When processing AES4000 images, the binarized image is
completely mangled and a lot of ridge information is lost.
Resizing the AES4000's small images results in a huge imaging performance
gain.
We use imagemagick for the resizing, as it's resizing code resamples the
image too (smoothing it out), which further improves performance.
