[fprint] Working with small sensors

[Indev]

I've heard that fprint matching doesn't work well with small sensors.

In my case (issue #162
<https://gitlab.freedesktop.org/libfprint/libfprint/-/issues/162>), the
device returns 114x57 images and there is probably not much minutiae to
extract. I am certain that it is a press sensor, even though it returns
multiple images during communication. Despite the fact that it's hard to
find any specification for the device, Acer Swift 3 promo
<https://www.youtube.com/watch?v=FgbYrSOy3oQ> shows exactly that.

When running enroll and then verify examples, I get "score 0" on every
verify.

Basically, my questions are:

   1. Is this a small sensor problem and is there really too little
   minutiae?
   2. What is the state of small sensors matching? Are there any working
   drivers for small sensors?
   3. How much minutiae is enough to work?
   4. In my driver code, how can i check minutiae count *before* calling
   fpi_image_device_image_captured, for example, to prevent submitting images
   with low minutiae count?
   5. What are other options to make my device work, maybe by using
   multiple images?
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