Installing OpenCV 3

Question

I have been trying to install opencv 3 but this github url(https://github.com/Itseez/opencv_contrib/archive/3.3.0.zip) seems not working. But the zip file is downloading when I'm entering above url in a browser. I have a Raspbian stretch installation in Raspberry Pi B3.

I'm following the instructions given in this page https://www.pyimagesearch.com/2017/09/04/raspbian-stretch-install-opencv-3-python-on-your-raspberry-pi/

But terminal is showing the error given below:

pi@raspberrypi:~ $ wget -O 3.4.1.zip https://github.com/opencv/opencv/archive/3.4.1.zip
--2018年05月16日 12:11:50-- https://github.com/opencv/opencv/archive /3.4.1.zip
Resolving github.com (github.com)... 192.30.253.113, 192.30.253.112
Connecting to github.com (github.com)|192.30.253.113|:443... failed: No route to host.
Connecting to github.com (github.com)|192.30.253.112|:443... failed: No route to host.

Can anyone please tell me what am I missing here? Or please give me a working url.

Answer 1

Installation in Linux

These steps have been tested for Ubuntu 10.04 but should work with other distrib as well.
It works on my pi 3 with raspbian stetch.

Required Packages

• GCC 4.4.x or later
  
• CMake 2.8.7 or higher
  
• Git
  
• GTK+2.x or higher, including headers (libgtk2.0-dev)
  
• pkg-config
  
• Python 2.6 or later and Numpy 1.5 or later with developer packages (python-dev, python-numpy)
  
• ffmpeg or libav development packages: libavcodec-dev, libavformat-dev, libswscale-dev
  
• [optional] libtbb2 libtbb-dev
  
• [optional] libdc1394 2.x
  
• [optional] libjpeg-dev, libpng-dev, libtiff-dev, libjasper-dev, libdc1394-22-dev
  

The packages can be installed using a terminal and the following commands or by using Synaptic Manager:

 [compiler] $ sudo apt-get install build-essential
 [required] $ sudo apt-get install cmake git libgtk2.0-dev pkg-config 
 libavcodec-dev libavformat-dev libswscale-dev
 [optional] $ sudo apt-get install python-dev python-numpy libtbb2 libtbb-dev 
 libjpeg-dev libpng-dev libtiff-dev libjasper-dev libdc1394-22-dev

Getting OpenCV Source Code

You can use the latest stable OpenCV version available in sourceforge or you can grab the latest snapshot from the Git repository.

Getting the Latest Stable OpenCV Version

• Go to the openCV page on Sourceforge;
• Download the source tarball and unpack it.

Getting the Cutting-edge OpenCV from the Git Repository

Launch Git client and clone OpenCV repository In Linux it can be achieved with the following command in Terminal:

 $ cd ~/<my_working _directory>
 $ git clone https://github.com/Itseez/opencv.git

Building OpenCV from Source Using CMake, Using the Command Line

1. Create a temporary directory, which we denote as <cmake_binary_dir>, where you want to put the generated Makefiles, project files as well the object files and output binaries.

2. Enter the <cmake_binary_dir> and type

   cmake [<some optional parameters>] <path to the OpenCV source directory>
   

   For example

   $ cd ~/opencv
   $ mkdir release
   $ cd release
   $ cmake -D CMAKE_BUILD_TYPE=RELEASE -D CMAKE_INSTALL_PREFIX=/usr/local ..
   

3. Enter the created temporary directory cmake_binary_dir and proceed with:

   $ make -j8 # -j8 runs 8 jobs in parallel.
    # Change 8 to number of hardware threads available.
   $ sudo make install
   

Note If the size of the created library is a critical issue (like in case of an Android build) you can use the install/strip command to get the smallest size as possible. The stripped version appears to be twice as small. However, we do not recommend using this unless those extra megabytes do really matter.

• smc: I'm unable to connect github. I have set a static IP. I can only ping to google.com.

Answer 2

Best and easily method for install openCV on Raspbian, I try more method and i find this, Install dependency library for opencv :

 sudo apt-get install libhdf5-dev libhdf5-serial-dev
 sudo apt-get install libqtwebkit4 libqt4-test
 sudo apt-get install libatlas-base-dev libjasper-dev libqtgui4 python3-pyqt5 

Finally

 sudo pip install opencv-contrib-python

test for install openCV on bash

 pi@raspberrypi:~/fcs $ python3
 Python 3.5.3 (default, Sep 27 2018, 17:25:39) 
 [GCC 6.3.0 20170516] on linux
 Type "help", "copyright", "credits" or "license" for more information.
 >>> import cv2
 >>> cv2.__version__
 '3.4.4'
 >>> 

enter image description here Reference Doc

• Ingo: Why don't just sudo apt install python3-opencv or python-opencv from the buster repository?
• Hamed: This is opencv-contrib-python Unofficial pre-built OpenCV packages for Python.The difference between this library and the main library is not, Please see this [link][pypi.org/project/opencv-contrib-python/]