Detect fingerprint image from ID card

asked 2019-06-28 23:15:02 -0500

Andres gravatar image

Hi All,

We are trying to run a POC where we get a picture of an ID card that contains a fingerprint image on it and the idea is to first detect where in the picture the fingerprint is located, draw a rectangle around the fingerprint and cut the content of the rectangle. Has anyone have done something similar? Any ideas on how to accomplish this would be great.

Thanks a lot

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please do some own research before asking, opencv has face recognition samples , that do exactly this.

berak gravatar imageberak ( 2019-06-28 23:29:31 -0500 )edit

Hi Berak,

I have checked the face recognition samples but they are quite different as in there the algorithm looks for eyes, the T zone, lips and so on. In my case we need to look for an scheletonized image of a fingerprint which has a white background.

Andres gravatar imageAndres ( 2019-06-28 23:34:28 -0500 )edit

apologies, i missed the fingerprints.

berak gravatar imageberak ( 2019-06-29 02:24:09 -0500 )edit

Should I create a new question? Or can you help me to reopen it?

Andres gravatar imageAndres ( 2019-06-29 05:37:31 -0500 )edit

I reopened the question - hope you don't mind @berak

Andres can you give an example of such an ID card? Do they follow a pattern? Can they be photographed in a fixed position?

Witek gravatar imageWitek ( 2019-07-01 20:11:36 -0500 )edit

Hi Witek

Please find at the following link some samples

drive.google.com/drive/folders/1ahFDI...

Andres gravatar imageAndres ( 2019-07-01 20:46:32 -0500 )edit

Is the fingerprint always on the white background and the dominant surrounding color of the ID is yellow? Can these documents be scanned or do they need to be photographed from a hand held camera?

Witek gravatar imageWitek ( 2019-07-02 18:07:21 -0500 )edit

Witek,

Here the answers

Is the fingerprint always on the white background and the dominant surrounding color of the ID is yellow? Yes, the document will be the same for everybody

Can these documents be scanned or do they need to be photographed from a hand held camera? they need to be taken from a camera

Andres gravatar imageAndres ( 2019-07-07 23:12:27 -0500 )edit

I would try adaptive thresholding followed by countour detection in order to find the white rectangle. It would be helpful however, if the IDs could be photographed on a dark background as the difference between dark (black) and yellow is much bigger than between yellow and white (when only the fingerprint area is photographed like in your samples). Then, the largest detected rotated rectangle would correspond to the whole ID, which could be straightened and the fingerprint area could be easily cropped. See here for example:https://gist.github.com/canca...

Witek gravatar imageWitek ( 2019-07-09 02:48:53 -0500 )edit