CODEWITHSUNDEEP
opencvc++-cli
Qbul3kZ
Qbul3kZ

Reputation: 158

cvtColor crashes on conversion

I load a frame from camera with external dll to my OpenCV program. I can see the frame cv::imshow("edges", frame); and everything is ok. frame.channels() gives me 3 channels but when I try to cv::cvtColor(frame, gray, CV_BGR2GRAY); application crashes.

CreateImage(System::Byte *imgData, int height, int width,int show)
{

    frame = cv::Mat(height, width, CV_8UC3, imgData);

    if (show > 0)
        cv::imshow("edges", frame); //I can see myself

    return frame.channels(); //three channels
}

void ConvertAndProcess()
{
    cv::Mat gray;

    cv::cvtColor(frame, gray, CV_BGR2GRAY); //crash...

    //do something
}

I've been digging for some time but no results. What am I doing wrong?

Upvotes: 1

Views: 2917

Answers (2)

skm
skm

Reputation: 5679

Check in void ConvertAndProcess() if the frame contains something or not. It seems like that the frame is empty and therefore there is nothing to convert from BGR to GRAY.

you can do the following:

if(!frame.empty())
    cvtColor(frame, gray, CV_BGR2GRAY);
else
{
    cout<<"\nFrame is empty.";
    return;
}

Upvotes: 2

berak
berak

Reputation: 39816

careful !

 frame = cv::Mat(height, width, CV_8UC3, imgData);

this is a 'borrowed' pointer. when imgData leaves scope (at the end of the function), frame.data is invalid.

that means, that you can't expect frame to be valid in ConvertAndProcess() if you constructed it this way.

you could clone() it, to achieve a 'deep copy':

 frame = cv::Mat(height, width, CV_8UC3, imgData).clone();

Upvotes: 5

Related Questions