peoblem with instalation

[WojciechowskiMarek]

CMake Error at /opt/ros/melodic/share/cv_bridge/cmake/cv_bridgeConfig.cmake:113 (message):
Project 'cv_bridge' specifies '/usr/include/opencv' as an include dir,
which is not found. It does neither exist as an absolute directory nor in
'${{prefix}}//usr/include/opencv'. Check the issue tracker
'https://github.com/ros-perception/vision_opencv/issues' and consider
creating a ticket if the problem has not been reported yet.

Where could be error ?

[dvigne]

Do you have OpenCV installed?

[ntomer]

I found a similar problem. I Installed opencv with 'sudo apt install python3-opencv python-opencv'.
hrrnxt@RUA-X-Ubuntu:~$ sudo apt install python3-opencv python-opencv Reading package lists... Done Building dependency tree Reading state information... Done python-opencv is already the newest version (3.2.0+dfsg-4ubuntu0.1). python3-opencv is already the newest version (3.2.0+dfsg-4ubuntu0.1). 0 upgraded, 0 newly installed, 0 to remove and 56 not upgraded.
However there is no path '/usr/include/opencv' but there is '/usr/include/opencv4/opencv2'

[Benefe]

I have the same problem. Like @ntomer there is also only '/usr/include/opencv4/opencv2' instead of '/usr/include/opencv'.
Maybe #209 and #316 might help.
This solved it for me:
I copied the fork of @OAkyildiz mentioned in #321 into catkin_ws/src and run catkin_make.

[ntomer]

I think there has been a change of opencv version behind the scenes.

Once I updated the path I had to modify the package that was using 'vision_opencv' with:
(remove)#include <cv.h>
(add)#include "opencv2/opencv.hpp"

And then remove some code which looks like it has been outdated. like the following lines:
namedWindow("Acquisition", CV_WINDOW_NORMAL | CV_WINDOW_KEEPRATIO);
cvDestroyAllWindows();

This all compiled before for me.

When I run:
python2 -c "import cv2; print(cv2.version)"
and
python3 -c "import cv2; print(cv2.version)"
the output is 4.0.0
but listing the python installs with: apt list python*opencv
Listing... Done
python-opencv/bionic-updates,bionic-security,now 3.2.0+dfsg-4ubuntu0.1 amd64 [installed]
python3-opencv/bionic-updates,bionic-security,now 3.2.0+dfsg-4ubuntu0.1 amd64 [installed]

suggesting the package is called 3.2 but programmatically identified as 4.0?

That would explain why #321 fixes the problem.

[AlexW159]

Hey. I have the same problem.
But sorry, I do not really get how you both solved it...

Clone the 'vision_opencv' packet from @OAkyildiz into ~/catkin_ws/src ....
After catkin build I get the next CMake Error:
`

CMake Error at /home/nuc-falke/catkin_ws/src/vision_opencv/cv_bridge/CMakeLists.txt:16 (find_package):

Could not find a configuration file for package "OpenCV" that is compatible

with requested version "3".

The following configuration files were considered but not accepted:
/usr/lib/x86_64-linux-gnu/cmake/opencv4/OpenCVConfig.cmake, version: 4.1.1

`

What am I doing wrong?
Or is there something else faulty?

[Benefe]

You might need to edit the required OpenCV version from 3 to 4 in the CMakeLists.

find_package(OpenCV 4 REQUIRED COMPONENTS opencv_core opencv_imgproc opencv_imgcodecs CONFIG )

Another solution mentioned in #316 might be sudo apt purge ros-melodic-cv-bridge and then build with catkin_make.
The difference is, you used catkin build instead of catkin_make

I hope this solves your problem.

[AlexW159]

Is there a significant difference between catkin build and catkin_make?
As I read, catkin build is just a newer and more advanced version of catkin_make (and some other variations)...

I used catkin build, because catkin_make has a problem with my non-homogeneous workspace.
I have a mavlink 'package' in it which seems to be (plain cmake) (a communication protocol for UAS from PX4).
And catkin build handles that issue; that's why I used it so far. The Error message suggest to use catkin_make_isolated which I am not famliar with yet, and I don't know how to use...

I installed sudo apt purge ros-melodic-cv-bridge,
and I changed the OpenCV 3 REQUIRED COMPONENTS to OpenCV 4 REQUIRED COMPONENTS.
Now I am getting cv::MatAllocator errors:

• abstract type 'NumpyAllocator'
• no member named 'refcount'
  and so on...
  

[Benefe]

I understand. The file in which the error occurs is module_opencv2.cpp, by using opencv2 functions which are not implemented in opencv4.
But as in the CMakeLists.txt of cvBridge defined it should use the corresponding file to the version of opencv. In our case opencv4. So the problem is either CMake does not recognize the version of opencv correctly or opencv4 is not installed correct.
I would suggest to clone the vision_opencv repo from @OAkyildiz into an empty directory, so git isn't able to merge files and make sure that only opencv4 is installed or CMake could only access opncv4.

[AlexW159]

I am kind of confused with my installed opencv versions...
When executing the commands @ntomer mentioned, i get:
$python2 -c "import cv2; print(cv2.__version__)"
4.3.0-dev
and
$python3 -c "import cv2; print(cv2.__version__)"
4.2.0

And like @ntomer said, when requestin the apt for the installed packages, it lists:
$apt list python*opencv
Listing... Done
python-opencv/bionic-updates,bionic-security,now 3.2.0+dfsg-4ubuntu0.1 amd64 [installed]
python3-opencv/bionic-updates,bionic-security,now 3.2.0+dfsg-4ubuntu0.1 amd64 [installed]

But before I changed the "REQUIRED OpenCV package from 3 to 4 on the CMakeLists.txt, the CMake Error said:

CMake Error at vision_opencv/cv_bridge/CMakeLists.txt:16 (find_package):
  Could not find a configuration file for package "OpenCV" that is compatible
  with requested version "3".

  The following configuration files were considered but not accepted:

    /usr/local/lib/cmake/opencv4/OpenCVConfig.cmake, version: 4.3.0
    /usr/lib/x86_64-linux-gnu/cmake/opencv4/OpenCVConfig.cmake, version: 4.1.1 

So it found version 4.3.0 and 4.1.1.

However, with the command I got from #316 :
$ pkg-config --modversion opencv
Package opencv was not found in the pkg-config search path. Perhaps you should add the directory containing 'opencv.pc' to the PKG_CONFIG_PATH environment variable
No package 'opencv' found
...he says he could not find an opencv package

@Benefe:
I cloned the vision_opencv repo from @OAkyildiz into an empty directory and empty catkin_ws,
so now I am also able to run catkin_make. However, the errors remain the same.
Regarding your last comment: How can I check which version CMake recognizes? Or might this also be caused by the suggestion @ntomer made :

package is called 3.2 but programmatically identified as 4.0?

Or how do I remove/deinstall all opencv files from my system, so that I can do a plain reinstall?

[Benefe]

In fact it is quite confusing with your installed opencv versions and with the versions make can find.
sudo find / -name "*opencv*" -exec rm -i {} \;
as in Removing all installed OpenCV libs
recommended should do the job.

I think with your command:

$apt list python*opencv
Listing... Done
python-opencv/bionic-updates,bionic-security,now 3.2.0+dfsg-4ubuntu0.1 amd64 [installed]
python3-opencv/bionic-updates,bionic-security,now 3.2.0+dfsg-4ubuntu0.1 amd64 [installed]

you get the python wrapped opencv libraries.

[espentrydal]

I fixed it with a small change in /opt/ros/melodic/share/cv_bridge/cmake/cv_bridgeConfig.cmake. Just replacing opencv with opencv4 on line 96 so it becomes

set(_include_dirs "include;/usr/include;/usr/include/opencv4")

Melodic installed with apt install ros-melodic-desktop, and opencv installed with apt install python-opencv.

[Benefe]

Nice! Thanks, I totally forgot about that.

[AlexW159]

@espentrydal, thank you, that fix sounds reasonable as well.

However, I actually decided to remove OpenCV completely and go back to version 3.4 for now, which works perfectly fine. But I will keep that in mind.

Thanks to all from my side.

[OAkyildiz]

In fact it is quite confusing with your installed opencv versions and with the versions make can find.
sudo find / -name "*opencv*" -exec rm -i {} \;
as in Removing all installed OpenCV libs recommended should do the job.

I think with your command:

$apt list python*opencv
Listing... Done
python-opencv/bionic-updates,bionic-security,now 3.2.0+dfsg-4ubuntu0.1 amd64 [installed]
python3-opencv/bionic-updates,bionic-security,now 3.2.0+dfsg-4ubuntu0.1 amd64 [installed]

you get the python wrapped opencv libraries.

I think there has been a change of opencv version behind the scenes.

Once I updated the path I had to modify the package that was using 'vision_opencv' with:
(remove)#include <cv.h>
(add)#include "opencv2/opencv.hpp"

And then remove some code which looks like it has been outdated. like the following lines:
namedWindow("Acquisition", CV_WINDOW_NORMAL | CV_WINDOW_KEEPRATIO);
cvDestroyAllWindows();

This all compiled before for me.

When I run:
python2 -c "import cv2; print(cv2.version)"
and
python3 -c "import cv2; print(cv2.version)"
the output is 4.0.0
but listing the python installs with: apt list python*opencv
Listing... Done
python-opencv/bionic-updates,bionic-security,now 3.2.0+dfsg-4ubuntu0.1 amd64 [installed]
python3-opencv/bionic-updates,bionic-security,now 3.2.0+dfsg-4ubuntu0.1 amd64 [installed]

suggesting the package is called 3.2 but programmatically identified as 4.0?

That would explain why #321 fixes the problem.

I am looking into it right now, but what you are seeing might be the OpenCV that comes with ROS being linked

[OAkyildiz]

I have installed OpenCV 4.1 again when I flashed my JetsonTX2 with Nvidia SDK manager. After installing ROS I was able to catkin build cv_bridge with my fork for #321.

If you are trying to build other packages while having issues with this you can also use '--start-with' argument but it is more likely to be a CMakeFile error

[OAkyildiz]

UPDATE: I received the same error. Removing built packages and rebuilding workspace solved it:
catkin clean -bldy #use [catkin_tools]( https://catkin-tools.readthedocs.io/en/latest/installing.html)

catkin build -j