# Revision history [back]

### Why cuda::ORB detectAndCompute's useProvidedKeypoints parameter is forced to be false?

Hi Everyone,

I would like to use cuda::orb compute or detectAndCompute method to describe keypoints that I detect earlier. But when I try to use these methods I got "Assertion failed (useProvidedKeypoints == false) in detectAndCompute" error. When I search on the source code, I see

void ORB_Impl::detectAndCompute(InputArray _image, InputArray _mask, std::vector<KeyPoint>& keypoints, OutputArray _descriptors, bool useProvidedKeypoints){

CV_Assert( useProvidedKeypoints == false );
...


Why does the function takes a useProvidedKeypoints parameter that is forced to be equal to false?

Is there another way to achieve my goal?

Code Sample :

    cv::cuda::GpuMat gpu_img;
cv::cuda::GpuMat dst;