Convert an image to grayscale

Question

Is there a way to convert an image to grayscale 16 bits per pixel format, rather than setting each of the r,g and b components to luminance. I currently have a bmp from file.

Bitmap c = new Bitmap("filename"); 

I want a Bitmap d, that is grayscale version of c. I do see a constructor that includes System.Drawing.Imaging.PixelFormat, but I don't understand how to use that. I'm new to Image Processing and the relevant C# libraries, but have a moderate experience with C# itself.

Any help, reference to an online source, hint or suggestion will be appreciated.

EDIT: d is the grayscale version of c.

Answer 1

"I want a Bitmap d, that is grayscale. I do see a consructor that includes System.Drawing.Imaging.PixelFormat, but I don't understand how to use that."

Here is how to do this

Bitmap grayScaleBP = new           System.Drawing.Bitmap(2, 2, System.Drawing.Imaging.PixelFormat.Format16bppGrayScale); 

EDIT: To convert to grayscale

             Bitmap c = new Bitmap("fromFile");              Bitmap d;              int x, y;               // Loop through the images pixels to reset color.              for (x = 0; x < c.Width; x++)              {                  for (y = 0; y < c.Height; y++)                  {                      Color pixelColor = c.GetPixel(x, y);                      Color newColor = Color.FromArgb(pixelColor.R, 0, 0);                      c.SetPixel(x, y, newColor); // Now greyscale                  }              }             d = c;   // d is grayscale version of c   

Faster Version from switchonthecode follow link for full analysis:

public static Bitmap MakeGrayscale3(Bitmap original) {    //create a blank bitmap the same size as original    Bitmap newBitmap = new Bitmap(original.Width, original.Height);     //get a graphics object from the new image    using(Graphics g = Graphics.FromImage(newBitmap)){         //create the grayscale ColorMatrix        ColorMatrix colorMatrix = new ColorMatrix(           new float[][]            {              new float[] {.3f, .3f, .3f, 0, 0},              new float[] {.59f, .59f, .59f, 0, 0},              new float[] {.11f, .11f, .11f, 0, 0},              new float[] {0, 0, 0, 1, 0},              new float[] {0, 0, 0, 0, 1}           });         //create some image attributes        using(ImageAttributes attributes = new ImageAttributes()){             //set the color matrix attribute            attributes.SetColorMatrix(colorMatrix);             //draw the original image on the new image            //using the grayscale color matrix            g.DrawImage(original, new Rectangle(0, 0, original.Width, original.Height),                        0, 0, original.Width, original.Height, GraphicsUnit.Pixel, attributes);        }    }    return newBitmap; }