Shawn Weisfeld [MVP]

Remove Background

In my earlier post I put together an image processing class (http://drowningintechnicaldebt.com/blogs/shawnweisfeld/archive/2006/11/06/Bitmap-Processing-in-C_2300_.aspx). I needed a method that did some segmentation based on a given color. It needed to take in the color and a threshold and it would black out any pixels that are not within the color threshold. Here is the code:

public static Bitmap RemoveBackground(Bitmap b, Color c, int threshold)
{
    ImagerBitmap i = new ImagerBitmap(b.Clone() as Bitmap);
    int maxGreen = c.G + threshold;
    int minGreen = c.G - threshold;
    int maxRed = c.R + threshold;
    int minRed = c.R - threshold;
    int maxBlue = c.B + threshold;
    int minBlue = c.B - threshold;

    for (int column = 0; column < i.Bitmap.Width; column++)
    {
     for (int row = 0; row < i.Bitmap.Height; row++)
     {
         Color px = i.GetPixel(column, row);

         if (px.G > minGreen && px.G < maxGreen
          && px.R > minRed && px.R < maxRed
          && px.B > minBlue && px.B < maxBlue)
         {
          //i.SetPixel(column, row, Color.FromArgb(255, 255, 255));
         }
         else
         {
          i.SetPixel(column, row, Color.Black);
         }
     }
    }
    i.UnlockBitmap();
    return i.Bitmap.Clone() as Bitmap;
}