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I'd like to detect if a logo image in user's camera view - for example if the logo of StackOverflow was printed on a paper and viewed through camera. Or for less complicated approach let's say that I'd like to detect it in a bitmap. I'd like to recognize if one specific logo - it's possible to hardcode it to the app.

Is it even possible with using of open-source libraries like OpenCV or would it require lots and lots of man-hours to implement?

Ovidiu Latcu
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Axarydax
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This is a clear case for invariant moments matching (look into wikipedia about Hu Moments). And I'm developing free opensource library which uses it for text tecognition on android:

http://sourceforge.net/projects/javaocr/

There are android demos, demonsrtating complete roundtrip - sampling, training and recognition. Here is market application showcasing it:

https://market.android.com/details?id=de.pribluda.android.ocrcall&feature=search_result#?t=W251bGwsMSwxLDEsImRlLnByaWJsdWRhLmFuZHJvaWQub2NyY2FsbCJd

( Support for the library through mailing lists )

I would say, that implementing recognition for just one logo will take me anout 5-6 hours.

Addition: OpenCV is a big library writen in C, and just integrate it into android is major PITA

Konstantin Pribluda
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This is possible with opencv but might still require lots and lots of man-hours depending on your definition of lots and lots.

On a more serious note: start at template matching. If that is not enough for you perhaps SIFT features are. Also, search this site, there are some pretty good discussions about stuff like this to be found.

Community
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jilles de wit
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  • opencv is C, and this means native mode in android - means major PITA. it is also way too big - user acceptance for 10MB big apps is very limited – Konstantin Pribluda Feb 17 '12 at 20:03
  • @jilles - lots and lots are tens of hours - compared to something in plug and play fashion. As the entire rest of the project would take maybe 6 hours and template matching/sift/surf would take 60 hours, I don't think it's a good idea to start working on this – Axarydax Feb 17 '12 at 20:40