What format should I use to convert QImage to cv::Mat?

Aaron Kim

auto image = this->myLabel->pixmap()->toImage();
this->background = Mat(image.height(), image.width(), CV_8UC3, const_cast<uchar*>(image.bits()), static_cast<unsigned int>(image.bytesPerLine())).clone();
this->myLabel->setPixmap(mat2QPixmap(this->background, QImage::Format_RGB888));

This code does not seem to work.

I guess that this happens because I chose the incorrect format.

mrjj

Hi
Yes could be wrong format.
Try code from here
http://qtandopencv.blogspot.com/2013/08/how-to-convert-between-cvmat-and-qimage.html
Cant promise it works as i never used cv.

SGaist

Hi,

Are you sure your cv::Mat object contains RGB data ?

Aaron Kim

@SGaist As you can see, the data were extracted from the QImage

auto image = this->myLabel->pixmap()->toImage();

So it must be RGB data.

SGaist

RGB, most likely, however it's likely not RGB888. You should check the format of your QImage object. As stated in the QPixmap::toImage documentation, it can be QImage::Format_ARGB32_Premultiplied for pixmaps with an alpha and QImage::Format_RGB32 or QImage::Format_RGB16 for pixmaps without alpha.