2014-05-30 01:50:07 -0600 | commented question | OpenCV returning NULL Descriptor Matrix Nope. The library OpenCV give for iOS is precompiled without debug flags. I have tried numerous times to compile from source but never come right and to be honest just don't have the time. |
2014-05-29 11:03:21 -0600 | asked a question | OpenCV returning NULL Descriptor Matrix I am trying to use OpenCV for generating descriptors at keypoints in an image on iOS. I have done feature detection using my own algorithm and now want to extract the descriptors at these points. I implemented the following code to do this: However the descriptors Mat is always empty after I run the "compute" function. All the pointers are just NULL, although I can clearly see that the keyPoints array is a reduced size after I run it. Which means that it is removing keypoints that it can't extract descriptors for. I thought it was my implementation so I used a built in detector (SurfDetector) and copied the implementation from the OpenCV FREAK example. But I end up with the same result. Is anyone else having issues, or have I missed something fundamental in OpenCV? |