How convert image from RGB model to HSV (without built-in functions) and display it in java?

Question

I try to convert image from RGB model to HSV and display it. Unfortunately I dont have any idea how to do this. I dont want to use built-in function but I want write function alone. I want to do this in similar way using RGB channels. I read/checked a lot of example from this site but I have not found any special and helpfull materials. Please help how should I do this.

// image from RGB to grayscale
private static BufferedImage monochromatyczny(BufferedImage obrazek)
{
    for(int x = 0; x < obrazek.getWidth(); x++)
        for(int y = 0; y < obrazek.getHeight(); y++)
        {
            int piksel = obrazek.getRGB(x, y);
            // kanały r,g,b
            int r = (piksel>>16) & 0xff;
            int g = (piksel>>8)     & 0xff;
            int b = (piksel)        & 0xff;

            int gray = (r+g+b)/3;
            piksel = (gray<<16) | (gray<<8) | gray;

            obrazek.setRGB(x,y,piksel);
        }
    return obrazek;
}

Answer 1

Good explanation how to convert color RGB -> HSV i'm found on http://www.rapidtables.com/convert/color/rgb-to-hsv.htm

You may to try this formula in your rgb_2_hsv function