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I have tried installing opencv on arch using the aur package. It has successfully installed but when I try to import opencv2 in python, I get the following error

ImportError: libhdf5.so.100: cannot open shared object file: No such file or directory

Not just python , even when I tried running a c++ sample code using this, I got the same error. I have tried searching the net, found a few people who faced a similar issue but still I am unable to fix it.

I have installed Open CV version 3.2

Jeru Luke
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Reuben_v1
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3 Answers3

11

There are multiple packages with similar names but only one that works.

If you have not yet installed OpenCV, run:

pacman -S opencv
pacman -S python-opencv

Install hdf5:

pacman -S hdf5

Note that instructions for Sikuli, which depends on OpenCV, indicate that a symbolic link is required in /usr/lib. A system upgrade can break the link, which will have to be recreated to point to the most recent version of the OpenCV Java library:

# ls -la /usr/lib/libopencv_java*
-rwxr-xr-x 1 root root 2225952 Jul 18 02:48 /usr/lib/libopencv_java440.so
lrwxrwxrwx 1 root root      20 Aug  5 22:42 /usr/lib/libopencv_java.so -> libopencv_java440.so

This can be accomplished using the ln command:

sudo su -
cd /usr/lib
rm libopencv_java.so
ln -s libopencv_java440.so libopencv_java.so
Mateen Ulhaq
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Reuben_v1
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  • Actually, base-devel and opencv-samples are not necessary for compiling c++. – user202729 Jan 31 '19 at 10:23
  • Note that `python-opencv` also needs to be installed due to the [recent splitting of the packages](https://github.com/archlinux/svntogit-packages/commit/18c2a5cf0241bf4ff902df7e7bcae4afd2832ebc#diff-3e341d2d9c67be01819b25b25d5e53ea3cdf3a38d28846cda85a195eb9b7203a). Also, `-Syu` is unnecessary. `-S` is sufficient. Regarding "There are multiple packages with similar names but only one that works.", I only see `opencv` in the official repos, though there are (as usual) a bunch of variations in the AUR, including `opencv-cuda`. – Mateen Ulhaq Apr 28 '21 at 10:48
6

In version 4, in the default configuration, compiling opencv requires hdf5 and vtk, however it's not listed as a dependency of opencv.

That is mentioned in the two bugs on archlinux page: 1, 2.

There are 2 possible workarounds:

  1. sudo pacman -S hdf5 vtk (takes about 231.24 MiB of memory)
  2. If your program don't require hdf5 and vtk, remove -lopencv_hdf and -lopencv_viz from /usr/lib/pkgconfig/opencv4.pc (in case the program use pkg-config), or remove the 2 flags while compiling.

Warning: If you use workaround 2, update of opencv package will revert those changes. You may want to add them as a NoUpgrade entry in pacman.conf (read man page for details), but the file will no longer be updated and something else may break.

user202729
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3

for opencv4

sudo pacman -Sy opencv vtk hdf5

optionally, install Qt

sudo pacman -Sy qt5-base qtcreator qt5-doc gdb cmake

create a CMake project in QtCreator

paste the following

CMakeLists.txt

cmake_minimum_required(VERSION 3.5)

project(opencv LANGUAGES CXX)

set(CMAKE_CXX_STANDARD 11)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

add_executable(opencv main.cpp)

find_package( OpenCV REQUIRED )
include_directories( ${OpenCV_INCLUDE_DIRS} )
target_link_libraries( opencv ${OpenCV_LIBS} )

main.cpp

#include <opencv2/opencv.hpp>
#include <iostream>

using namespace cv;
using namespace std;

int main(int argc, char** argv)
{
    if ( argc != 2 )
    {
        printf("usage: DisplayImage.out <Image_Path>\n");
        return -1;
    }
    Mat image;
    image = imread( argv[1], 1 );
    if ( !image.data )
    {
        printf("No image data \n");
        return -1;
    }
    namedWindow("Display Image", WINDOW_AUTOSIZE );
    imshow("Display Image", image);
    waitKey(0);
    return 0;
}
xitong
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