Image Processing in C#: Part 9 - Applying a Mean Removal
Another type of sharpening effect is mean removal. It works similarly to the standard sharpening, except it subtracts values from all the surrounding pixels evenly.
The grid which we used for this effect is as follows
| -1 | -1 | -1 |
| -1 | 11 | -1 |
| -1 | -1 | -1 |
This gives a much more noticeable sharpening effect on the image.
public void ApplyMeanRemoval(double weight)
{
ConvolutionMatrix matrix = new ConvolutionMatrix(3);
matrix.SetAll(1);
matrix.Matrix[0, 0] = -1;
matrix.Matrix[1, 0] = -1;
matrix.Matrix[2, 0] = -1;
matrix.Matrix[0, 1] = -1;
matrix.Matrix[1, 1] = weight;
matrix.Matrix[2, 1] = -1;
matrix.Matrix[0, 2] = -1;
matrix.Matrix[1, 2] = -1;
matrix.Matrix[2, 2] = -1;
matrix.Factor = weight - 8;
bitmapImage = Convolution3x3(bitmapImage, matrix);
}The full source used in the series is available from https://github.com/sjmeunier/image-processor.
Originally posted on my old blog, Smoky Cogs, on 19 Nov 2009