Can I use gpu::Stream for CascadeClassifier_GPU on OpenCV and how?

Question

I use Opencv 2.4.10 (current stable version). And I use gpu::CascadeClassifier_GPU::detectMultiScale to detection faces. I want to use it async with my CUDA-kernel-code which I launch in separate cudaStream_t . But by default CascadeClassifier_GPU launch in the default zero-stream that make impossible to launch anything async to this on GPU.

As I see here no way to use gpu::Stream for CascadeClassifier_GPU : OpenCV DOC link

• Can I use gpu::Stream for CascadeClassifier_GPU and how?
• If no, then in what version of OpenCV can I do it?

UPDATE : So far the only way I've found - use a separate CPU thread to perform the function of the gpu::CascadeClassifier_GPU::detectMultiScale and perform it on a separate GPU. But for this at least I need 2 GPUs.

Answer 1

CascadeClassifier_GPU uses mixed GPU/CPU implementation and performs extra synchronizations internally, that's why it doesn't support asynchronous mode with gpu::Stream parameter. In order to launch it asynchronously with your code, you need to use separate CPU thread for it.