iliTheFallen's profile - activity

Very thx tuannhtn. It seems they may help me in this.

Hi All,

Is there any pool or a kind of search engine that i can use to match implementations in OpenCV with the papers that they are based? Because i need to cite LK Optical Flow GPU implementation and explain some part of it.

Thanks in advance, Ilker

Hi All,

I've been trying to make use of GPU counterpart(i.e. the one running on CUDA) of Pyramidal LK method; however this method does not return approximately the same next-points as does its cpu counterpart. Here is how i implemented :

    lk                  = new PyrLKOpticalFlow();
    lk->useInitialFlow  = true;
    lk->winSize.width   = 4;
    lk->winSize.height  = 4;
    lk->iters           = 20;
    lk->maxLevel        = 5;
    cv::Mat status(1, num_points, CV_8UC1, (void*)out_lk_status);
    GpuMat dev_status;
    //For pts...
    cv::Mat prev_pts(1, num_points, CV_32FC2, (void*)pts_prev);
    cv::Mat cur_pts(1, num_points, CV_32FC2, (void*)out_pts_cur);
    cv::Mat i_cpu(310, 
                  470,
                  CV_8UC1,
                  (void*)(IMG[I]->imageData));
    cv::Mat j_cpu(310, 
                  470,
                  CV_8UC1,
                  (void*)(IMG[J]->imageData));
    GpuMat dev_prev_pts;
    GpuMat dev_cur_pts;
    GpuMat i_gpu(i_cpu);
    GpuMat j_gpu(j_cpu);

    dev_prev_pts.upload(prev_pts);
    dev_cur_pts.upload(cur_pts);
    lk->sparse(i_gpu,
               j_gpu,
               dev_prev_pts,
               dev_cur_pts,
               dev_status);
    dev_cur_pts.download(cur_pts);
    dev_status.download(status);

and this is the working copy of its cpu counterpart :

    cvCalcOpticalFlowPyrLK( IMG[I], IMG[J], PYR[I], PYR[J], points[0], points[1], nPts, cvSize(4,4), Level, status, 0, cvTermCriteria(CV_TERMCRIT_ITER|CV_TERMCRIT_EPS,20,0.03), CV_LKFLOW_INITIAL_GUESSES);

You can see the pixel results(for a particular pair of consecutive frames) in the following link.

prev_pts_gpu_pts_cpu_pts

What should i have suspicion of?

P.S. My OpenCV version is 2.4.8.2.

Kind Regards,
Ilker