OpenCV Crosscompile for ARM: highgui error (GTK2+) - opencv

I'm have build the OpenCV library from source for Zynq (ARM). But, OpenCV was build on the same PC for x86 (PC) also. Firstly, I can execute every example on my PC without any issues. Secondly, I am able to crosscompile and execute every program on the arm target, except the ones including highgui libraries, where I receive the following error:
OpenCV Error: Unspecified error (The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Carbon support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script) in cvShowImage, file /home/hristov/workspace/opencv/modules/highgui/src/window.cpp, line 534
terminate called after throwing an instance of 'cv::Exception'
what(): /home/user/workspace/opencv/modules/highgui/src/window.cpp:534: error: (-2) The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Carbon support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script in function cvShowImage
Yes, I have gone through the forum for solutions for this issue but some answers were unclear and I would like some more detail into this. I have created the OpenCV build for ARM build WITH_GTK and GTK2. Also installed libgtk2.0-dev, pkg-config
However, From another topic on this forum, I learned that the problem lies in setting up the pkg-config: http://answers.opencv.org/question/57945/opencv-gui-with-gtk-2-solved/
Q) Based on the above solution, Do you set the path for PKG_CONFIG_PATH on your ARM platform (Zynq) or on the PC platform (Ubuntu PC)? Because, it is already set to the described path on the ARM platform whereas it is different on the PC Linux platform. More details of the current path is shown below:
PKG_CONFIG_PATH in PC(Ubuntu):
/usr/local/lib/x86_64-linux-gnu/pkgconfig:/usr/local/lib/pkgconfig:/usr/local/share/pkgconfig:/usr/lib/x86_64-linux-gnu/pkgconfig:/usr/lib/pkgconfig:/usr/share/pkgconfig
PKG_CONFIG_PATH in ARM (Embedded platform):
/usr/local/lib/arm-linux-gnueabihf/pkgconfig:/usr/local/lib/pkgconfig:/usr/local/share/pkgconfig:/usr/lib/arm-linux-gnueabihf/pkgconfig:/usr/lib/pkgconfig:/usr/share/pkgconfig
If the pkg-config must be changed on my PC, to the /usr/lib/arm-linux-gnueabihf/pkgconfig/ location, I cannot find any pkg-config in that location. Should I create a new one, by copying the folder from my target?
Q) Also, Should the GTK libraries also be installed in the Target Embedded system (ARM)?
Hope someone can help me with this solution as I have rebuild the libraries umpteen times with many different solutions, but to no avail. Thanks!

Related

How to build openCV 3.3.0 with GStreamer on Windows

Having Gstreamer 1.22 successfully installed I'm not able to configure the project to build OpenCV. CMake isn't able to find GStreamer on my machine. Any ideas how two address this issue?
Just found the solution:
Cmake is using FindGstreamerWindows.cmake to find GStreamer on Windows, which is using internal an environment variable called "GSTREAMER_DIR" pointing to ..\gstreamer\1.0\x86_64.
Please make sure GSTREAMER_DIR exists on your machine.
I recently compile Opencv 4.2 with GStreamer on Windows. I use settings for GStreamer as on the following pictures. Make sure you point to correct .lib and include directories. all_Library is gstapp-1.0.lib etc, when configuraing CMAKE to compile OpenCV.
I use Opencv 4.2, CMake 3.17.0 release candidate and Gstreamer 1.16.2 MSVC 64-bit (VS 2019) developer and runtime installer. The whole process is described here install OpenCV on windows GStreamer tutorial
The important part is to set up environmental variables to find Gstreamer Runtime. Into system variable path: add
xxx\1.0\x86_64\bin
xxx\1.0\x86_64\lib
xxx\1.0\x86_64\lib\gstreamer-1.0
Gstreamer pipe from c++ opencv program to the web.

Why doesn't CLion link my project with OpenCV for Windows?

I'm attempting to use OpenCV for Windows as supplied by opencv.org in a project I'm building with JetBrains' CLion IDE. I've installed the opencv library and configured CLion (set(OpenCV_DIR) to reference the build directory under it, but CMake issues the warning:
Found OpenCV Windows Pack but it has no binaries compatible with your configuration.
You should manually point CMake variable OpenCV_DIR to your build of OpenCV library.
I've tried some of the older distributions from opencv.org with the same results. It appears CMake is locating the OpenCV libraries, but doesn't want to use them. Why, and how do I get the OpenCV libraries to work under CLion?
The short answer is, you will probably need to build OpenCV from source in order to use it with CLion. But given the number and range of partially answered and unanswered questions here* and elsewhere on using JetBrains' CLion IDE with the OpenCV library, I think an overview is needed (my notes are from CLion 2016.3 and OpenCV 3.1, YMMV):
Though not produced by JetBrains, CMake is very central to CLion's operation. Understanding CMake therefore helps greatly in diagnosing CLion build problems. In particular CMake maintains a disk "cache" of settings which you may need to clear to incorporate changes to your environment (Tools->CMake->Reset Cache and Reload Project).
To make use of OpenCV in your build you must specify it in your project's CMakeLists.txt file. You request that CMake locate your OpenCV location and link it to your TARGET. An example of a sequence of commands from CMakeLists.txt for an executable named mushroom follows:
add_executable(mushroom ${SOURCE_FILES})
FIND_PACKAGE(OpenCV REQUIRED)
TARGET_LINK_LIBRARIES(mushroom ${OpenCV_LIBS})
(For more on FIND_PACKAGE, see CMake:How To Find Libraries.)
FIND_PACKAGE for package XXX works either by way of FindXXX.cmake files located at CMake's Modules directory, or by consulting environment variable XXXX_DIR. On my system, no FindOpenCV.cmake file was present, so I relied on the OpenCV_DIR environment variable instead. This must be set, not to the root of your OpenCV installation, but to the build folder beneath it. I used an entry in CMakeLists.txt to set this variable, e.g.:
set(OpenCV_DIR C:/Users/myacct/AppData/Local/opencv-3.0.0/build)
To link with OpenCV, CMake uses either FindOpenCV.cmake or OpenCV_DIR (see previous point above) to locate a file named OpenCVConfig.cmake. This file is generated by and ships with a particular build of OpenCV in order to document what components are present and where they are located.
Problems may occur when variable names used by OpenCVConfig.cmake conflict with those CLion has stored in its environment. In particular, if your OpenCV was built by Microsoft Visual C (MSVC), as is the Windows distribution from opencv.org, it won't work with CLion.
Because CLion's build toolchain (ControlAltS-toolchain) uses either MinGW or Cygwin, OpenCVConfig.cmake will search for OpenCV binaries under a subdirectory named mingw or cygwin and will find none because the binaries were built with MSVC (it will look in a directory like vc11 or vc12 instead). This probably means you will need to build OpenCV from source in order to use it with CLion.
Would reconfiguring OpenCVConfig.cmake to point to the MSVC binaries make this work? you may ask. Unfortunately the answer is still no, because libraries built with one compiler typically cannot be linked with another one.
OpenCVConfig.cmake or FindOpenCV.cmake likely contain diagnostic messages, but when CLion executes CMake for you, message(STATUS) calls are not displayed. To make them display, change them to message(WARNING) or message(FATAL_ERROR). But CLion 2016.3 EAP relieves this problem; see https://stackoverflow.com/a/39398373/5025060.
CLion does not indicate which .cmake script issued which diagnostics; don't assume they all come from the same script.
Hopefully this provides some general guidance on resolving CLion / CMake / OpenCV compatibility problems. Note that this does not cover compiler or linker issues; these will not appear until CMake completes its initial makefile build. Compiler or linker issues occur at a later stage and are controlled by include*(), link*() and other commands in CMakeLists.txt.
*Some related SO questions:
OpenCV Windows setup with CLion
OpenCV CLion (Cmake) linking issue - cmake reports a strange error
use OpenCV with Clion IDE on Windows
Compiling OpenCV on Windows with MinGW
Could not find module FindOpenCV.cmake ( Error in configuration process)
CMake: Of what use is find_package() if you need to specify CMAKE_MODULE_PATH anyway?

Compiling OpenCV-contrib for IOS (especially the SFM-Module)

I've tried to install openCV_contrib for IOS, therefore I execute
python opencv/platforms/ios/build_framework.py "framework_dest"
on my Mac (I need Xcode for compiling openCV for IOS) but all the times, i got the message:
-- Checking SFM deps... FALSE
-- Module opencv_sfm disabled because the following dependencies are not found: Glog/Gflags
I need the SFM module, hence I tried installing Glog and Gflags at several ways: using
brew install glog gflags
and brew outputs, that those packages are successfully installed respective already installed.
Later I tried to compile both from GitHub on my own, but with no success, I'm still not able to compile SFM for IOS.
On Linux I could compile openCV including the SFM module, but I can't compile it for IOS, because Xcode is not available for Linux.
I don't know, what to do! Do some of you know how to install glog/gflags on Mac or do you know how to build the IOS-Framework of OpenCV on Linux or maybe how to build the IOS-Framework on my Mac using the binaries created with cmake .. && make in my Linux (because there SFM is compiled)?
There have to be some solution, because Mac is based on Linux, so if it works on Linux, why doesn't it work on my Mac?!
Thanks!

OpenCv program is not able to run ; pkg-config is hashed

I am working with opencv libraries. When I run my project, I get following error:
OpenCV Error: Unspecified error (The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Carbon support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script) in cvNamedWindow, file /home/krathi/softwaresetup/opencv-2.4.9/modules/highgui/src/window.cpp, line 483
terminate called after throwing an instance of 'cv::Exception'
what(): /home/krathi/softwaresetup/opencv-2.4.9/modules/highgui/src/window.cpp:483: error: (-2) The function is not implemented. Rebuild the library with Windows, GTK+ 2.x or Carbon support. If you are on Ubuntu or Debian, install libgtk2.0-dev and pkg-config, then re-run cmake or configure script in function cvNamedWindow
When I go to terminal and type "type pkg-config" I get this:
pkg-config is hashed (/usr/bin/pkg-config)
I dont know what this means , but I guess that the access to pkg-config is only to the admin user of my machine. Am I right?
What should I do to fix this error ? Specifically what should I do so that my program can use pkg-config.
Note :I have installed libgtk
You probably have compiled OpenCV by yourself looking at the folders given in the error message. You need to recompile OpenCV by setting WITH_GTK=ON using cmake.

Cross Compiling a library from intel to arm

I am using open source C++ library DCMTK from http://dicom.offis.de/dcmtk.php.en.
I have successfully compiled this library on Windows using VC++ IDE, MacOS Xcode, Mac iOS simulator.
But I am not able to compile this library on iOS device as it is ARM based architecture.
DCMTK library compiled very well on Intel architecture.
Now my problem statement is :-
I need to compile this DCMTK C++ library on ARM architecture by cross compilation.
I am using Ubuntu 64 bit machine for cross compilation.
I have installed binaries from GNU ARM tool chain from http://www.gnuarm.com/
I am using GCC toolchain 4.0 binutils-2.16.1, gcc-4.0.2-c-c++, newlib-1.14.0, insight-6.4, TAR BZ2 [65.5MB] binaries for Ubuntu 64 bit machine for ARM cross compilation.
After Installing these binaries on Ubuntu I have set PATH environment variable to
PATH=$PATH/gnu_arm/bin
For configuring the DCMTK C++ library I have run the following command on shell
CC=arm-elf-gcc CXX=arm-elf-g++ AR=arm-elf-ar RANLIB=arm-elf-ranlib ARFLAGS=cruv ./configure –prefix=$home_dicom –target=arm-elf –host=arm-elf –enable-std-includes –disable-threads
It creates a make file properly. Now I am trying to compile the code by using make command, but facing so many compilation errors like :-
1) I tried to compile my first dependent C++ library that is ofstd.
I got error for DIR*, struct dirent, opendir(), closedir() calls.
It includes for these calls, but I did not found any definitions for the above calls in this header file.
2) When I compile another library oflog I got the following errors like
error: nthos was not declared in this scope
error: ntohl was not declared in this scope
error: htons was not declared in this scope
error: htonl was not declared in this scope.
These calls are networking calls and are not defined in any of the header file from GNU ARM tool.
I tried to download the sources of ARM binaries and extracted the tar files and try to copy missing header files to installed GNU ARM on Ubuntu.
For some files it compiles after doing changes to copied header files, and for some again it gives compilation errors.. There is a loop of compilation errors for every file present under DCMTK library as some of the standard header files are missing.
Please suggest if there is any other tool chain available for ARM cross compilation on Ubuntu 64 bit machine.
Or any other good solution apart from this.
Thanks!!!
Amit
There are many areas for problems when it comes to cross compiling. There are three main flags for cross compiling. -host , -target, and -build. The -host flash is the machine in which the resulting binaries will run on. The -build flash is the system in which you will be compiling on. The -target flag is for building libraries that will be used in cross compiling. So if you were to build your own gcc tool chain. So in your case you won't set the target flag as we're not building a tool chain. the -host flag will be arm-elf. And the -build flag will be amd64.
Usually a cross compilation fails if there are inconsistencies between the regular c compiler and the cross compiler. I have compiled several libraries for the avr32 with a toolchain generated by buildroot, but in some cases (socat project for example) it hasn't been possible.
Your host, your target and the CXX flags look ok. I think it is not necessary to put the AR flag (that is the idea with the host and target option).
In other hand, this is an example for the expat libraries for the avr32:
./configure --host=avr32-linux --prefix=/home/juan/builds/build_expat/ CC=avr32-linux-gcc
make; make install
I can recommend you that tries to cross compile from an ia32 architecture. I had several problems with that ubuntu in the past.

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