I have a problem trying to get a webcam in OpenCV 2.3 to work with Cygwin. I have a Windows 7 64-bit system and I use Notepad++ and cygwin compilers to do my C++ programming. I have seen other posts with similar problems:
Getting Webcam to work in OpenCV
Can't access webcam with OpenCV
I first tried installing OpenCV via the Cygwin Ports. This is rather easy to install, but alas I run into the webcam problem (always returns false when trying to find a device). I have also attempted to build OpenCV and install manually using the command line flavor of CMake. I tried adding the HAVE_VIDEOINPUT and HAVE_DSHOW flags, but no dice. All my programs compile nicely and I have all the functionality of OpenCV aside for this webcam thing.
Has anyone successfully built OpenCV 2.3 on Cygwin with webcam working?
It is unlikely that cygwin build of OpenCV will be able to access a webcam. At least it is not possible without hacking OpenCV cmake scripts. Under cygwin OpenCV build always follows the UNIX branch and videoinput/directshow is excluded from build.
Related
I have OpenCV 3.4 installed in Ubuntu 18. I also have installed ROS Melodic according to the website instructions. However, I keep on getting an error that libopencv_core.so.3.2 is required.
I already set my CMakeLists files to point to OpenCV 3.4.
However, I found out that in the file:
/ros/melodic/share/cv_bridge/cmake/cv_bridgeConfig.cmake
there is the following line hardcoded in opencv3.2:
set(libraries "cv_bridge;/usr/lib/x86_64-linux-gnu/libopencv_core.so.3.2.0;/usr/lib/x86_64-linux-gnu/libopencv_imgproc.so.3.2.0;/usr/lib/x86_64-linux-gnu/libopencv_imgcodecs.so.3.2.0").
I tried to change it to 3.4 but I can not rebuild it.
The error I am getting is:
/opt/ros/melodic/lib/image_view/image_view: error while loading shared libraries: libopencv_core.so.3.2: cannot open shared object file: No such file or directory
Why is OpenCV 3.2 hardcoded in cv_bridge and how can I rebuild it with OpenCV 3.4?
Update:
I eventually installed OpenCV 3.2 and it worked properly.
Because opencv development speed is much faster than ROS individual module. And a lot of ROS modules went depreciated after someone left the job.
But that's by no means the end of the day( maybe end of the day for noobs). You can build it directly with any version of opencv core function(besides imshow kind of function) others should perform just fine.
The easiest way is to do is: in the console before executing catkin_make try to execute the following
export CMAKE_PREFIX_PATH=/usr/local:$CMAKE_PREFIX_PATH
export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH
This should give preference to your custom OpenCV installation when doing the find_package(OpenCV 3.X.0 REQUIRED). Then compile and use the function of that version.
Well if you do have to use 3.4 then I think you have to build ros version of opencv and image transport and cvbridge to the 3.4 if that's what you are targeting.
You can find the link here https://github.com/ros-gbp/opencv3-release The highest they provide seems to be 3.3
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.
I have a java code that uses OpenCV. Right now I just have to try to run that code. My Mac doesn't have OpenCV. And I need to download 2.4.13 version of OpenCV. I downloaded certain things but I do not understand the exact steps to make it run with my java code. Can someone help me and tell the exact steps to install OpenCV 2.4.13 and run my java code with it?
I am trying to install the Projector-Camera Calibration software available on: http://mesh.brown.edu/calibration/ . The software demands having installed Qt 4.8.4 and OpenCV 2.4.3 on my computer. It cannot work (as far as i know according to my research and INSTALL.txt file in the installation package) with any other versions of Qt and OpenCV. My problem is that OpenCV 2.4.3 version is no longer available anywhere on the Internet to download. It is not even available on the official OpenCV website: http://opencv.org/releases.html . I've tried downloading other versions of OpenCV, but none of them seems to work with this calibration software. More specifically, when I try to execute nmake release command in my Developer Command Prompt for VS 2017, the
LINK : fatal error LNK1181: cannot open input file
'opencv_core243.lib'
message is displayed which is expected because other versions of OpenCV do not have opencv_core243.lib file. I've done everything demanded in INSTALL.txt file, the PATH variable is set properly and everything else.
Can anybody help me with this problem or send me a link for downloading the OpenCV 2.4.3 if it is available somewhere on the Internet?
I don't see why the library should be dependent on that version of OpenCV. From my experience, the camera calibration functions are very stable through different versions.
You should be able to build the library with other versions of OpenCV by editing the file projector-calib.pro from:
# Windows 7
win32:OPENCV_DIR = "C:/opencv/opencv-2.4.3/opencv/build"
win32:OPENCV_LIB_DIR = $$OPENCV_DIR/x86/vc10/lib
win32:CV_VER = 243
to:
# Windows 7
win32:OPENCV_DIR = "C:/{YOUR_PATH}/opencv/build"
win32:OPENCV_LIB_DIR = $$OPENCV_DIR/{x64/x86}/vc12/lib
win32:CV_VER = {VERSION}
and substituting {YOUR_PATH}, {X64/X86} and {VERSION} properly. For OpenCV 2.4.13, for example, {VERSION} is 2413.
I have started to work on Rpi. I have worked on opencv on windows and ubuntu. Now I want to do Image porcessing on Rpi. I have installed latest version 2.4.8 on my Rpi. And I am able to open and display an image. However when I am trying to open webcam and display, it gives me error: HIGHGUI ERROR: v4l/v4l2: VIDIOC_CROPCAP.
Can anyone tell whats the problem ?
I haved the some error when trying to execute a code that does facedetection , i solved it by adding the files needed in my working folder (source folder).
you can show us the code to find out what exactly you need
If you are using prebuilt binaries, they may be built without v4l support. Try to build your own OpenCV with v4l checked. And of course before that install v4l with development files. You can follow this tutorial with how to install required dependicies explanied.