cv::Mat detect PixelFormat

Question

I'm trying to use pictureBox->Image (Windows Forms) to display a cv::Mat image (openCV). I want to do that without saving the Image as a file ('cause i want to reset the image every 100ms). I just found that topic here: How to display a cv::Mat in a Windows Form application?

When i use this solution the image appears to be white only. I guess i took the wrong PixelFormat. So how do figure out the PixelFormat i need? Haven't seen any Method in cv::Mat to get info about that. Or does this depend on the image Source i use to create this cv::Mat? Thanks so far :)

Here i took a screen. Its not completely white. So i guess there is some color info. But maybe i'm wrong. Screen

Answer 1

cv::Mat.depth() returns the pixel type, eg. CV_8U for 8bit unsigned etc. and cv::Mat.channels() returns the number of channels, typically 3 for a colour image

For 'regular images' opencv generally uses 8bit BGR colour order which should map directly onto a Windows bitmap or most Windows libs.

SO you probably want system.drawing.imaging.pixelformat.Format24bppRgb, I don't know what order ( RGB or BGR) it uses but you can use the opencv cv::cvtColor() with CV_BGR2RGB to convert to RGB

Answer 2

Thanks for the help! The problem was something else. I just did not allocate memory for the Image Object. So there was nothing to really display. Using cv::Mat img; in the headerFile and img = new cv::Mat(120,160,0); in Constructor (ocvcamimg Class) got it to work. (ocvcamimg->captureCamMatImg() returns img).