How to print and verify that MatDescriptors are non-empty?? [closed]

asked 2013-02-07 07:58:10 -0600

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For example, suppose I run following snippet

Mat descriptors;
std::cout << descriptors.empty << std::endl; // writes 0
extractor.compute( object, keypoints, descriptors );
std::cout << descriptors.empty << std::endl; //  writes 0

So, as you can see even after calling extractor.compute(), descriptors are empty. So, how can one figure out that compute() was called and processed successfully.

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Closed for the following reason the question is answered, right answer was accepted by SR
close date 2013-06-15 17:08:23.981699

Comments

http://www.cplusplus.com/reference/vector/vector/

sammy gravatar imagesammy ( 2013-02-07 08:24:37 -0600 )edit

descriptors are not vectors, they are of Mat-type. So I guess, your pointer won't suffice.

Abhinav gravatar imageAbhinav ( 2013-02-07 11:37:06 -0600 )edit

My fault. You are right. Check the docs for cv::Mat. It's as easy as reading the doc page.

sammy gravatar imagesammy ( 2013-02-07 13:01:28 -0600 )edit

You answered your question already (except that you code misses brackets after empty such as std::cout<<descriptors.empty()<<std::endl;. Why there are no descriptors is an entirely different question. You may have detected or specified no keypoints for example.

SR gravatar imageSR ( 2013-06-15 17:05:52 -0600 )edit
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