GPU based optical flow extraction in OpenCV

Features:

• OpenCV wrapper for Real-Time optical flow extraction on GPU
• Automatic directory handling using Qt
• Allows saving of optical flow to disk,
  • either with clipping large displacements
  • or by adaptively scaling the displacements to the radiometric resolution of the output image

Dependencies

• OpenCV 2.4
• Qt 5.4
• cmake

Installation

1. mkdir -p build
2. cd build
3. cmake ..
4. make
5. sudo make install

Usage:

./compute_flow [OPTION]...

Available options:

• --input-dir: directory containing video files
• --output-dir: directory to dump frames and flow to
• --start-video: start with video number in vid_path directory structure
• --gpu-id: use this GPU ID
• --method: use this flow method Brox = 0, TVL1 = 1
• --step: specify the number of frames between sampled frames used to compute optical flow
• --min-size=256: defines the smallest side of the frame for optical flow computation
• --output-size=256: defines the smallest side of the frame for saving as .jpeg
• --clip-flow/--clip-flow=false: defines whether to clip the optical flow larger than [-20 20] pixels and maps the interval [-20 20] to [0 255] in grayscale image space. If no clipping is performed the mapping to the image space is achieved by finding the frame-wise minimum and maximum displacement and mapping to [0 255] via an adaptive scaling, where the scale factors are saved as a binary file to out_path.

Docker

$ docker run --runtime=nvidia --rm -t \
    --volume /path/to/video-dir:/video \
    --volume  /path/to/output:/output \
    willprice/gpu_flow:latest