Hi, is it possible to implement a customized bagOfFeatures with a SIFT extractor? and detector?

I'm using MATLAB R2014b version with computer vision toolbox. I'm trying to generate classifiers with different types of extractors to analyse handwritten words, and for that i'm making use of bagOfFeatures function. MATLAB doesn't have a SIFT extractor code but it's possible to implement it or use David Lowe's version. How can i use this SIFT extractor (and detector) with the bagOfFeatures function?

Thanks

[shalaw faraj]

Dear Arthur Costa,

did you get the code of Bag of features based on SIFT? if you got it please give it to me.

thanks

Answer 1

[Anand]

If you can upgrade to a later version (R2015a or higher), you can use the 'CustomExtractor' name-value pair to do this. Unfortunately, this wasn't part of R2014b.

http://www.mathworks.com/help/releases/R2015a/vision/ref/bagoffeatures-class.html

[Arthur Costa]

Thanks! I was searching for it at the wrong version

[Adit Chawdhary]

Is there a Custom Extractor file available for SIFT feature extraction?

Answer 2

[Image Analyst]

SIFT is still patented by the University of British Columbia for a few more years. I believe the Computer Vision System Toolbox uses SURF instead.

[Arthur Costa]

Thanks! That's one reason. But for research purposes they have provided a demo software at David Lowe's page: http://www.cs.ubc.ca/~lowe/keypoints/

But it doesn't run properly. I keep getting an error with 'Invalid keypoint file beginning'

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