Display RGB HALCON image as QImage

[rujma]

@SGaist I did not check the values since I am not sure what I am looking for in comparison with the original image.

[SGaist]

Compare the CountChannels values, the width and height values.

[rujma]

@SGaist I can answer the Width and Height question. When I use the InterleaveChannels method, the width is 4x larger than the original image, while the height stays the same. I tried to divide by 4 when constructing the QImage as shown in the matching example, but no luck.

[SGaist]

What do you get if using the sizes returned by your interleaved image ?

[rujma]

@SGaist Pretty sure it is the same thing as the one on the printscreen. The division by 4 did not make a difference (I think). But I shall confirm it on my test setup tomorrow.

[SGaist]

Are you also sure that you choose the correct image format for QImage ?

[rujma]

@SGaist I have tried several, mainly _ARGB, _RGB888, _Premultiplied, .... all unsuccessfully.

[rujma]

@SGaist said in Display RGB HALCON image as QImage:

What do you get if using the sizes returned by your interleaved image ?

While showing the interleaved image, it is "wider" compared with the screen shot image. I think is due to the fact that the width is 4x higher.

[ollarch]

This is because instead of an image that contains 3 channels each one containing only R or G or B values, you now have one image that have only 1 channel containing RGBA values. When you get the image pointer you have width*4 that is correct. "width" is not really the image width, is the "bytes per line" in this case.

What happens if you use this QImage contructor?

QImage qimage(imgRawPtr, width / 4, height, width, QImage::Format_RGB32);

[rujma]

@ollarch said in Display RGB HALCON image as QImage:

This is because instead of an image that contains 3 channels each one containing only R or G or B values, you now have one image that have only 1 channel containing RGBA values. When you get the image pointer you have width*4 that is correct. "width" is not really the image width, is the "bytes per line" in this case.

What happens if you use this QImage contructor?

QImage qimage(imgRawPtr, width / 4, height, width, QImage::Format_RGB32);

The image is exactly the same as the one on the screenshot, nothing changed.

[ollarch]

Could you try to save the processed image to disk and check it?

[rujma]

@ollarch said in Display RGB HALCON image as QImage:

Could you try to save the processed image to disk and check it?

I have saved the images using the following code:

            _currentHImage.WriteImage("png", 0, "images/himage");
            
                        HalconCpp::HImage interleavedImg = _currentHImage.InterleaveChannels("argb", "match", 0); // Only if the image is RGB
            
                        unsigned char* imgRawPtr = (unsigned char *)interleavedImg.GetImagePointer1(&type, &width, &height);
            
                        QImage qimage(imgRawPtr, width / 4, height, width, QImage::Format_RGB32);
            
                        qimage.save("images/qimage.png");

The images are equal! The only problem is showing them on the paint.drawImage....

[rujma]

Looks like I was using the wrong format and not scaling the image correctly.
This is the fix:

if(_currentHImage.CountChannels().I() == 3)
        {
            HalconCpp::HImage interleavedImg = _currentHImage.InterleaveChannels("argb", "match", 0); // Only if the image is RGB
            unsigned char* imgRawPtr = (unsigned char *)interleavedImg.GetImagePointer1(&type, &width, &height);
            QImage qimage(imgRawPtr, width / 4, height, width, QImage::Format_RGB32);
            QImage newqimage = qimage.scaled(400, 300, Qt::KeepAspectRatio);
            QPainter painter(this);
            painter.drawImage(QPoint(0, 0), newqimage);
        }
        else
        {
            unsigned char* imgRawPtr = (unsigned char*)_currentHImage.GetImagePointer1(&type, &width, &height);
            QImage qimage(imgRawPtr, width, height, QImage::Format_Grayscale8);
            QImage newqimage = qimage.scaled(400, 300, Qt::KeepAspectRatio);
            QPainter painter(this);
            painter.drawImage(QPoint(0, 0), newqimage);
        }
}

Thanks for all your help!

[SGaist]

Nice !

Since you have it working now, please mark the thread as solved so other forum members may know a solution has been found :-)