Optical_Flow_Extraction_GPU_Opencv3

Extracting optical flow based on GPU in Opencv3

Preface

This code was adapted from https://github.com/feichtenhofer/gpu_flow and we truly appreciate the work of feichtenhofer. The most of the detailed information can be seen in that repository.

Install Opencv3

My opencv version is 3.4.3. It will appear some problems when making opencv3 according to official documents. It concludes that following command is fine.

cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_INSTALL_PREFIX=/usr/local -D WITH_CUDA=ON -D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib/modules -D BUILD_TIFF=ON ..

Explaination of Output

The defaulted optical flow values are truncated to lie [-20, 20], and mapped to [0, 255] for JPG compression. The outputs are three channels JPG images. BGR of the image represents x, y, and magnitude of the optical flow value, respectively.

Example

./compute_flow --gpuID=0 --type=1 --skip=1 --vid_path xxx --out_path xxx