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Thinning

Started by Ructions Jan 10, 2005 at 10:36 AM 3 replies 800+ views

Original Post

Jan 10, 2005 at 10:36 AM

i am making a fingerprint recongition system and am in the process at the moment in thinning the fingerprint image into 1 pixel in width. but am having trouble doing this. i have search the internet and have got no real help. could any of ye point me in right direction where i might be able to get some sample source code so help me along. Thanks in advance Ructions

benryves

526

benryves

Jan 10, 2005 at 11:25 AM

I don't know what sort of pixel format you're using, so I'll use some bad sample code - hopefully it makes sense:

for (int y=0; yint brightness = 0;
for (int x=0; xbrightness += getpixel(source,x,y);
}
brightness /= source.width;
setpixel(dest,0,y,brightness);
}

dave j

118

dave j

Jan 10, 2005 at 3:28 PM

Do you mean you're trying to make the lines making up the fingerprint 1 pixel wide? If so you need to implement an erode filter. Have a look at this page on morphological filters. If you just want a program to do it, or a library to call, look at netpbm. If you want an example implementation you could look there as well since it's open source.

dave j

Ructions

Author

Ructions

Jan 11, 2005 at 8:10 AM

that a great help. but do you know any implementation of thinning in C++/C#. where i could get source code.

Thanks in advance

Ructions

dave j

118

dave j

Jan 11, 2005 at 2:40 PM

I don't I'm afraid. netpbm is written in C, although it won't have an OO interface, it will do erode filters. Unless you can find someone who has released code specifically for fingerprint analysis, I doubt you'll get anything more suitable than that - or one of the other open source image processing libraries.

dave j

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