Search code examples
c#winformspictureboxpixelyuv

YUV color space and chrominance

Ok. To be short suppose:

  1. I have a monochrome image; And initially it represented in RGB color space.

  2. I don't know in what sequence I shall do this, but I need to convert image to YUV space (a) and load it into PictureBox control (b) and make few color scribbles;

  3. And finally I need to learn/know somehow what pixels were colored.

    And how do I draw lines/dots on loaded image in PictureBox?

Have any ideas?

Solution

  • Converting a monochrome image from RGB to YUV is very simple:

    Y = R
U = 0
V = 0

    Y is the luminance, calculated as 0.299 * R + 0.587 * G + 0.114 * B, but as R = G = B for a monochome image, it's the same as (0.299+0.587+0.114) * R which is simply 1 * R.

    U is calculated as 0.436 * ((B - Y) / 0.886), but as Y = B it is always zero.

    V is calculated as 0.615 * ((R - Y) / 0.701), but as Y = R it is alwaus zero.

    To draw lines on a Bitmap object, you use the Graphics.FromImage method to create a Graphics object for it, then use the DrawLine method to draw lines.

    To draw pixels, use the SetPixel method of the Bitmap object.