Greyscale vs. Monochrome fingerprints

General information about Neurotechnology and its software

Greyscale vs. Monochrome fingerprints

Postby jmargel » Jan 07, 2010 15:55

Right now I'm working with grayscale fingerprints, however I am at the stage to start devlopment on state police fingerprint cards which goto the FBI. These grayscale prints do not show well at all on black and white color laser printers. However most of the police departments we are working with don't have color laser printers.

So, I might have to develop an option to use monochrome fingerprints. I have a couple of questions:

Does this technology work better (ie. enrolling and matching) grayscale prints over monochrome prints?

Can a monochrome fingerprint match upto a grayscale print and vice-versa?

Do you know if the FBI can take grayscale prints?

I tried doing a search and replace on the NGrayScaleImage to NMonochromeImage however I was getting errors in the Data.NFExtractor.Extract function. I have not spent anytime researching this, it could be just a simple error, not sure yet. I was using the VB sample provided with the SDK. Verifinger 6.2

Thanks,

Jeff
jmargel
 
Posts: 56
Joined: Oct 28, 2009 12:20

Re: Greyscale vs. Monochrome fingerprints

Postby Martynas » Jan 08, 2010 08:37

Hello,

NFExtractor accepts only NGrayScale images. It is not possible to use NMonochrome images with extractor. Even if it would be possible it would lead to worse extraction of fingerprint templates and this would lead to worse matching of fingerprints.
As I understand you need monochrome images only for printing. So you can extract fingerprint templates from grayscale images. Later convert these images to monochrome only for printing task.
Another possibility is to use a binarized fingerprint image, which can be returned by the extractor. Before doing extraction you can choose what kind of image will be returned after the extraction (returnde image is not a template) - it is possible to get not changed image (the same as it was used for input), binarized image (filtering algorithms are applied to image), skeletonized image.
Best regards,

Martynas
Software Consultant
Neurotechnology
Martynas
Neurotechnology
 
Posts: 2234
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Location: Vilnius, Lithuania

Re: Greyscale vs. Monochrome fingerprints

Postby jmargel » Jan 08, 2010 13:45

Thank you for the reply. I converted a grayscale fingerprint image to black and white with a photo editor and it did not come out good. I was just wondering if I would have gotten a better image by scanning monochrome. My thinking was that the matching would not be good either with a black and white.

I will have to find what is acceptable, if they can accept grayscale images. I'm going to have to do some researching on who to contact at the FBI.

Thanks,

Jeff
jmargel
 
Posts: 56
Joined: Oct 28, 2009 12:20


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