// Image Preprocessing
private Bitmap ImagePreprocessing(Bitmap image, int threshold)
{
// Grayscale
image = Grayscale.CommonAlgorithms.RMY.Apply(image);
// Edge Detection (using CannyEdgeDetector)
image = new CannyEdgeDetector().Apply(image);
// Noise Removal
int startX, startY, endX, endY;
startX = image.Width;
startY = image.Height;
endX = 0;
endY = 0;
for (int i = 0; i < image.Width; i++)
{
for (int j = 0; j < image.Height; j++)
{
if (image.GetPixel(i, j).R > threshold)
{
if (i < startX)
{
startX = i;
}
if (j < startY)
{
startY = j;
}
if (i > endX)
{
endX = i;
}
if (j > endY)
{
endY = j;
}
}
}
}
image = image.Clone(new Rectangle(startX, startY, endX - startX, endY - startY), PixelFormat.Format8bppIndexed);
// Resize
image = new ResizeBilinear(32, 32).Apply(image);
return(image);
}
public Bitmap preprocessing(Bitmap image)
{
image = image.Clone(new Rectangle(0, 0, image.Width, image.Height), System.Drawing.Imaging.PixelFormat.Format24bppRgb);
image = Grayscale.CommonAlgorithms.BT709.Apply(image);
image = new Threshold(127).Apply(image);
image = new CannyEdgeDetector().Apply(image);
int x = image.Width;
int y = image.Height;
int width = 0;
int height = 0;
for (int i = 0; i < image.Height; i++)
{
for (int j = 0; j < image.Width; j++)
{
if (image.GetPixel(j, i).R > 127)
{
if (x > j)
{
x = j;
}
if (y > i)
{
y = i;
}
if (width < j)
{
width = j;
}
if (height < i)
{
height = i;
}
}
}
}
image = image.Clone(new Rectangle(x, y, width - x, height - y), System.Drawing.Imaging.PixelFormat.Format24bppRgb);
image = new ResizeBilinear(10, 10).Apply(image);
return(image);
}