Hi, I am getting RGB videofeed from a camera and I am storing it in a PixBuf, from this PixBuf I wish to be able to acquire the shade (grayscale) value of pixels located at a particular x and y location.
I have looked at the put_pixel() example in the API reference http://www.gtk.org/api/2.6/gdk-pixbuf/gdk-pixbuf-gdk-pixbuf.html I acquired the red/green/blue values from the p[0]..p[2] values and then I performed the following transformation that should give me a grayscale image 0.299*Red+0.587*Green+0.114*Blue. I then attempted to test out how it would acquire pixel values so what I did was I took a white sheet of paper and drew thick black lines to see if they can be detected amongst the white paper. When I checked the values I noticed that there was almost no difference between the pixels that were white and black. On the other hand if I covered up the whole viewport of the camera I would get very low values and if I put a light source right up to it I would get really high values. I am wondering why it isn't detecting the dark lines on a sheet of paper but it does detect it if I cover the whole camera so it's dark or make it very bright. I was wondering if may be due to the fact that the example is for RGBA images and not RGB and the calculations for Pixel would be different for RGB images although this dosen't necessarily make sense to me since it assumes they are 8 bit images. Thanks for the help, Michal _______________________________________________ gtk-app-devel-list mailing list gtk-app-devel-list@gnome.org http://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
