OpenCV integration

[pherthyl]

Not sure why you're getting that. Have you tried looking at the dst image before you convert it to a QImage (using the highgui showimg function)? Make sure the dst image is the correct bit depth (8u or 8s).

[eumesmo]

Hello pherthyl,


Thanks for the framework, it's very good, but I found a problem running in my hardware. I tested the framework in a Hp notebook, with the webcam and with a external camera and worked fine. When a tried the framework in another notebook (a LG note) with the integrate webcam, a get an deadlock every time I stop and try a play again.

The console output: (this problem in this notebook occurs every time, it's not a random problem...)


Listing capture properties...
CV_CAP_PROP_FRAME_WIDTH
CV_CAP_PROP_FRAME_HEIGHT
CV_CAP_PROP__FPS 0
CV_CAP_PROP_FOURCC 0
CV_CAP_PROP_BRIGHTNESS 0
CV_CAP_PROP_CONTRAST 0
CV_CAP_PROP_SATURATION 0
CV_CAP_PROP_HUE 0
Done
Setting 640x480 1
Attempting to set frame rate...
Error: 0
Starting to track
About to start the capture thread
Started the capture thread
Stop capture requested.
Waiting on capture start...
Listing capture properties...
CV_CAP_PROP_FRAME_WIDTH
CV_CAP_PROP_FRAME_HEIGHT
CV_CAP_PROP__FPS 0
CV_CAP_PROP_FOURCC 0
CV_CAP_PROP_BRIGHTNESS 0
CV_CAP_PROP_CONTRAST 0
CV_CAP_PROP_SATURATION 0
CV_CAP_PROP_HUE 0
Done
Setting 640x480 1
Attempting to set frame rate...
Error: 0
Starting to track
About to start the capture thread
Started the capture thread
QMutex::lock Deadlock detected in thread 3916



Well, another test that I did, it's to start a HeadTracker object when a button is pressed in the main window. Well, it works fine until I request a re-size. After a re-size the program crashes and close.


It's just a report, but any help it's very welcome, I will have a better lock in the code to see if I can improve anything, because I think is a very good framework and really fast as well

cheers!

[mounte]

I know this thread is quite old, but still it is a very good wrapper to get images from webcam or whatnot.

If for some reason you dont need some fancy 32 bit format you could change the updatePixmap function to only use one memcpy like this:

QTime t;
    t.start();
    //qDebug() << "Copying data";
    bool start = false;
    // check if the frame dimensions have changed
    if(frame->width != imageWidth || frame->height != imageHeight) {
        if(imageData) {
            delete[] imageData;
        }
        start = true;
        imageWidth = frame->width;
        imageHeight = frame->height;
        emit(frameSizeChanged(imageWidth, imageHeight));
        imageData = new unsigned char[3*imageWidth*imageHeight];
    }
 
    int pixels = imageWidth * imageHeight;
    uchar* src = (uchar*)(frame->imageData);
 
    memcpy(imageData, src, pixels*3);
    if(!start) {
        ++frames;
        time += t.elapsed();
    }

QTime t;
    t.start();
    //qDebug() << "Copying data";
    bool start = false;
    // check if the frame dimensions have changed
    if(frame->width != imageWidth || frame->height != imageHeight) {
        if(imageData) {
            delete[] imageData;
        }
        start = true;
        imageWidth = frame->width;
        imageHeight = frame->height;
        emit(frameSizeChanged(imageWidth, imageHeight));
        imageData = new unsigned char[3*imageWidth*imageHeight];
    }

    int pixels = imageWidth * imageHeight;
    uchar* src = (uchar*)(frame->imageData);

    memcpy(imageData, src, pixels*3);
    if(!start) {
        ++frames;
        time += t.elapsed();
    }

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Then you have to change the paintEvent method to create the tImg with RGB888 format like this:

QImage tImg(imageData, imageWidth, imageHeight, QImage::Format_RGB888);

QImage tImg(imageData, imageWidth, imageHeight, QImage::Format_RGB888);

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You might run into problem of RGB <--> BGR conversion, just modify the painter.drawImage call to

painter.drawImage(QPoint(0,0), tImg.rgbSwapped());

painter.drawImage(QPoint(0,0), tImg.rgbSwapped());

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