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problem with make in ubuntu #365
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Can you provide more info about your environment, like what opencv version you're using, how it was built, whether you've enabled opencv_contrib, etc.. The most important thing is to make sure you're using the correct version 3.3.0 You should start with the wiki, it has detailed installation instructions: |
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Thanks, I followed the link and mexopencv seems to install fine, however when I run the command cv.VideoCapture I get the following error |
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See the troubleshooting section of the wiki: Basically MATLAB bundles its own (often incompatible) version of some of the libraries that opencv also depends on, which explains the "missing symbol" errors. A possible solution is to force-load incompatible libraries, by preloading the system libs you built opencv against, rather than getting the (usually older) ones bundled with matlab. As explained in the wiki link above, you would do something like: (PS: MATLAB lists "GCC C/C++ 4.9.x" as compatible compilers for Linux, but Ubuntu 16.04 comes with gcc-5 by default I believe. That's likely to be a cause of problem too.) To find out which libraries are conflicting, run Sometimes you might need to check second dependencies. For instance: The above error suggests to me some sort of conflict in the Theora lib required by FFmpeg, which in turn is used by the videoio module. You would confirm by comparing: As a general tip, you can debug this sort of shared-libraries-loading-problems by using the |
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Thanks, I added the Preload libraries and now the cv.VideoCapture seems to start the camera. However when I try to capture images I get the following error : Would you have any suggestion on how to fix this? |
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Is this the same camera you mentioned in your other post? What I can suggest is to directly test with C++ code, to see if opencv is capable of grabbing frames from your camera in the first place. Like I explained before, assuming your camera is supported by OpenCV, you should pick the right backend in the Here is an example to get you started: #include <iostream>
#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;
int main()
{
// check the "Video I/O" section in the output, make sure your backend is enabled!
cout << getBuildInformation() << endl;
VideoCapture cap;
cap.open(0, cv::CAP_ANY); // try different backends here
if (!cap.isOpened()) {
cerr << "failed to initialize capturing" << endl;
return 1;
}
cout << "Capturing... Press any key to terminate" << endl;
Mat frame;
while (true) {
cap >> frame;
if (frame.empty()) break;
imshow("live", frame);
if (waitKey(5) >= 0) break;
}
cap.release();
return 0;
}If it doesn't work in C++ either, I would say this an issue/limitation of OpenCV itself, out of control of mexopencv. |
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Hi eghbalhosseini, Could you give me help? Thanks! |
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vlfeat/matconvnet#967 (comment) This issue has a solution that worked for me perfectly. |
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I am building mexopencv in ubuntu 16.04 but get the following error during make process
Please let me know if this a known problem and how it could be fixed.
Thanks,
Eghbal
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