Flow IO OpenCV

This is a fork and OpenCV wrapper of the optical flow input/output code provided as part of the Sintel dataset [1]. The code is based on imageLib, a small C++ library for multi-channel images based on the StereoMatcher [2] code by Daniel Scharstein and Richard Szeliski. We refer to:

• lib/README-FlowIO: the original README shipped with the Sintel dataset.

• lib/imageLib/README: the original README of imageLib shipped with the Sintel dataset.

• lib/imageLib/README-StereoMatcher: the original README of the StereoMatcher.

  [1] D. J. Butler, J. Wulff, G. B. Stanley, M. J. Black. A naturalistic open source movie for optical flow evaluation. In European Conference on Computer Vision, pages 611 - 625, 2012. [2] D. Scharstein, R. Szeliski. A taxonomy and evaluation of dense two-frame stereo correspondence algorithms. Technical Report MSR-TR-2001-81, Microsoft Research, 2001.

Compile

The OpenCV wrapper is based on CMake and (surprise!) OpenCV (for example, follow Installing OpenCV on Linux to install OpenCV). The code has been tested on Ubuntu 14.04 and 14.10.

$ sudo apt-get install cmake build-essential libboost-all-dev
$ mkdir build
$ cd build
$ cmake ..
$ make
$ ./cli/cli --help
Allowed options:
  --help                produce help message
  --input-dir arg       input directory
  --output-dir arg      output directory
  --vis-dir arg         visualize results in a separate directory

The provided command line tool can be used to convert .flo files to .txt files using the cv::FileStorage format. Additionally, the tool provides visualization capabilities. For example:

$ ./cli/cli ../alley_1_flow ../alley_1_cflow --vis-dir ../alley_1_flow_vis

The result is shown below:

Usage

A usage example is provided in cli/main.cpp:

// Define input file and output (visualization) path (or directly output file).
boost::filesystem::path in_file(...);
boost::filesystem::path out_dir(...);
boost::filesystem::path vis_dir(...);

cv::Mat flow = FlowIOOpenCVWrapper::read(in_file.string());

boost::filesystem::path txt_path = out_dir / in_file.filename();
IO::writeMat(txt_path.string() + ".txt", flow);

if (visualize) {
    cv::Mat image = FlowIOOpenCVWrapper::flowToColor(flow);

    boost::filesystem::path image_path = vis_dir / in_file.filename();
    cv::imwrite(image_path.string() + ".png", image);
}

License

See lib/README-FlowIO.md and lib/imageLib/README.md for license information. The OpenCV wrapper and the corresponding command line tool are licensed as follows:

Copyright (c) 2015, David Stutz All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice,this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
• Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.