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Nevermind, I found a solution to the first issue: My application requires the key points to be sorted according to their response. While the CPU version does it automatically, the GPU versions don't. Unfortunately, I accidentally sorted (only) the key points but not the corresponding descriptors. Clearly, this caused a mismatch when indexing collected key points and descriptors in the training phase of my SVM.

IIRC, the problem arised somehow from the (OCL module) documentation which state:

At a minimuml level, it can be viewed as a set of accelerators, that can take advantage of the high compute throughput that GPU/APU devices can provide.

Even if this is somehow true, there are some essential differences which aren't documented (well) (e.g., the CPU version perform a sorting while the GPU versions don't).

In addition, it should be noted that there are some differences between CPU and GPU when comparing the descriptors (see also here). This is due some implementation aspects of the GPU. However, at least in my application, these differences seem to be acceptable.

I hope this helps someone else avoiding this pitfall.

Note, however, using the cv::ocl module still causes an application crash on termination.

Nevermind, I found a solution to the first issue: My application requires the key points to be sorted according to their response. While the CPU version does it automatically, the GPU versions don't. Unfortunately, I accidentally sorted (only) the key points but not the corresponding descriptors. Clearly, this caused a mismatch when indexing collected key points and descriptors in the training phase of my SVM.

IIRC, the problem arised somehow from the (OCL module) documentation which state:

At a minimuml level, it can be viewed as a set of accelerators, that can take advantage of the high compute throughput that GPU/APU devices can provide.

Even if this is somehow true, there are some essential differences which aren't documented (well) (e.g., the CPU version perform performs a sorting while the GPU versions don't).

In addition, it should be noted that there are some differences between CPU and GPU when comparing the descriptors (see also here). This is due some implementation aspects of the GPU. However, at least in my application, these differences seem to be acceptable.

I hope this it helps someone else in avoiding this pitfall.

Note, however, using the cv::ocl module still causes an application crash on termination.