Merge pull request spmallick#462 from vkoriukina/vk/opencv-gpu

added code for OpenCV GPU Support

Author: vikasgupta-github

OpenCV-GPU-Support/README.md

@@ -0,0 +1,189 @@
+# OpenCV GPU Support
+
+This repository contains the code for [OpenCV GPU Support](https://www.learnopencv.com/opencv-gpu-support/)
+
+## Getting Started
+
+Our code is tested using Python 3.7.5, but it should also work with any other python3.x. If you'd like to check your
+version run:
+
+```bash
+python3 -V
+```
+
+### Virtual Environment
+
+Let's create a new virtual environment. You'll need to install [virtualenv](https://pypi.org/project/virtualenv/)
+package if you don't have it:
+
+```bash
+pip install virtualenv
+```
+
+Now we can create a new virtualenv variable and call it `env`:
+
+```bash
+python3 -m venv env
+```
+
+The last thing we have to do is to activate it:
+
+```bash
+source  env/bin/activate
+```
+
+### Numpy
+
+Install numpy package by running:
+
+```bash
+pip install numpy
+```
+
+### Installing CUDA
+
+The code was tested using CUDA Toolkit 10.2. Please follow the official instruction to download
+[CUDA Toolkit 10.2](https://developer.nvidia.com/cuda-10.2-download-archive) or higher.
+
+### OpenCV with CUDA Support
+
+In this blog post, we're using OpenCV with CUDA support to accelerate OpenCV algorithms. That is why we will need to
+customize the OpenCV library build and make it from scratch. To do so:
+
+1. Install dependencies:
+
+```bash
+sudo apt-get update
+sudo apt-get install build-essential cmake unzip pkg-config
+sudo apt-get install libjpeg-dev libpng-dev libtiff-dev
+sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev
+sudo apt-get install libxvidcore-dev libx264-dev
+sudo apt-get install libgtk-3-dev
+sudo apt-get install libatlas-base-dev gfortran
+sudo apt-get install python3-dev
+
+```
+
+2. Download the latest OpenCV version from the official repository:
+
+```bash
+wget -O opencv.zip https://github.com/opencv/opencv/archive/4.4.0.zip
+wget -O opencv_contrib.zip https://github.com/opencv/opencv_contrib/archive/4.4.0.zip
+```
+
+3. Unzip the downloaded archives:
+
+```bash
+unzip opencv.zip
+unzip opencv_contrib.zip
+```
+
+4. Rename the directories to match CMake paths:
+
+```bash
+mv opencv-4.4.0 opencv
+mv opencv_contrib-4.4.0 opencv_contrib
+```
+
+5. Compile OpenCV:
+
+Create and enter a build directory:
+
+```bash
+cd opencv
+mkdir build
+cd build
+```
+
+Run CMake to configure the OpenCV build. Don't forget to set the right pass to the `PYTHON_EXECUTABLE`. If you are using
+the CUDA version different from `10.2`, please change the last 3 arguments accordingly.
+
+```bash
+cmake -D CMAKE_BUILD_TYPE=RELEASE \
+      -D CMAKE_INSTALL_PREFIX=/usr/local \
+      -D INSTALL_PYTHON_EXAMPLES=OFF \
+      -D INSTALL_C_EXAMPLES=OFF \
+      -D OPENCV_EXTRA_MODULES_PATH=../../opencv_contrib/modules \
+      -D PYTHON_EXECUTABLE=env/bin/python3 \
+      -D BUILD_EXAMPLES=ON \
+      -D WITH_CUDA=ON \
+      -D CUDA_FAST_MATH=ON \
+      -D WITH_CUBLAS=ON \
+      -D CUDA_TOOLKIT_ROOT_DIR=/usr/local/cuda-10.2 \
+      -D OpenCL_LIBRARY=/usr/local/cuda-10.2/lib64/libOpenCL.so \
+      -DOpenCL_INCLUDE_DIR=/usr/local/cuda-10.2/include/ \
+      ..
+```
+
+Check the output and make sure that everything is set correctly. After that we're ready to build it with:
+
+```bash
+make -j4
+```
+
+Make sure, you didn't get any errors. Then run the following command:
+
+```bash
+sudo ldconfig
+```
+
+which creates the necessary links and cache to our freshly built shared library.
+
+Rename the created Python3 bindings for OpenCV to `cv2.so`:
+
+```bash
+mv lib/python3/cv2.cpython-37m-x86_64-linux-gnu.so cv2.so
+```
+
+The last step is to create a symlink of our OpenCV `cv2.so` into the virtual environment installed packages:
+
+```bash
+cd env/lib/python3.7/site-packages/
+ln -s ~/opencv/build/cv2.so cv2.so
+```
+
+## Running the Demo
+
+**C++**
+
+You first need to compile .cpp file with the following command:
+
+```bash
+g++ `pkg-config --cflags --libs opencv4` demo.cpp -o demo.out -lopencv_core -lopencv_highgui -lopencv_imgcodecs -lopencv_imgproc -lopencv_videoio -lopencv_video -lopencv_cudaarithm -lopencv_cudaoptflow -lopencv_cudaimgproc -lopencv_cudawarping -std=c++11
+
+```
+
+After that to run the demo, you will need to pass:
+
+- path to the video file,
+- device, to choose between CPU and GPU inference. By default, the device is set to "cpu".
+
+For example:
+
+```bash
+./demo.out video/boat.mp4 gpu
+```
+
+**Python**
+
+To run the demo, you will need to pass:
+
+- `--video` argument to set the path to the video file,
+- `--device` to choose between CPU and GPU inference. By default, the device is set to "cpu".
+
+For example:
+
+```bash
+python3 demo.py --video video/boat.mp4 --device "cpu"
+```
+
+
+# AI Courses by OpenCV
+
+Want to become an expert in AI? [AI Courses by OpenCV](https://opencv.org/courses/) is a great place to start.
+
+<a href="https://opencv.org/courses/">
+<p align="center">
+<img src="https://www.learnopencv.com/wp-content/uploads/2020/04/AI-Courses-By-OpenCV-Github.png">
+</p>
+</a>