Camera input

[peteole]

Hi,

I am trying to build an optical fingerprint sensor with this library. The idea is to have a camera take pictures of a finger through a window and match them with older pictures. To the eye, the quality of the images looks pretty decent.
The template I get has about 100 edges and minutiae. When matching with the exact same image, I get a very big score, however, even the slightest change (for example take the same image, but a slightly different part of it) results in a score of 0.

Also I need to do some preprocessing with opencv to be able to parse any edges from the image.

Any idea what's going wrong? How "change-resistent" is this library intended to be? Should a slight movement or rotation of the image be tolerated?
And another thing: Do you have any tips on how to preprocess images to get better results with an optical camera?

Here you can find the source code:
https://github.com/peteole/smartWindowJava

Thanks in advance!

[robertvazan]

SourceAFIS tolerates translation and rotation. It does not tolerate scaling, i.e. DPI change. SourceAFIS also tolerates reasonable amount of image noise. Could you send me two matching images that yield zero score? You can send them via private message/email. I will take a look.

[peteole]

Hmm I'm feeling a bit stupid now, actually I don't find your mail anywhere, could you send it please?

[robertvazan]

I was hoping you would visit my profile and follow link to my homepage:

https://robert.machinezoo.com/

My current email address is always there.

[robertvazan]

I've looked at the images and there are a few obvious issues:

• the image is not grayscale
• low contrast
• large areas of the fingerprint are not illuminated
• fingerprint should be dark, background bright
• 400 DPI is way off

You need to do a bit more image processing and adjust the DPI. If problems persist, send me new images for evaluation.