/// <summary>
/// Subtract b2 from b1 and normalize the image
/// </summary>
/// <param name="b1">Image</param>
/// <param name="b2">Image</param>
/// <returns>Normalized Image</returns>
public static Bitmap Subtract(Bitmap b1, Bitmap b2)
{
if (b1.Width != b2.Width || b1.Height != b2.Height)
throw new Exception("Images not the same size cannot subtract");
ImagerBitmap i = new ImagerBitmap(b1.Clone() as Bitmap);
ImagerBitmap i2 = new ImagerBitmap(b2.Clone() as Bitmap);
int[,] red = new int[i.Bitmap.Width, i.Bitmap.Height];
int[,] blue = new int[i.Bitmap.Width, i.Bitmap.Height];
int[,] green = new int[i.Bitmap.Width, i.Bitmap.Height];
int redMax = 0;
int redMin = 0;
int redRange = 0;
int blueMax = 0;
int blueMin = 0;
int blueRange = 0;
int greenMax = 0;
int greenMin = 0;
int greenRange = 0;
//fill the arrays with the subtracted values
//Keep track of the min and max values for later
for (int column = 0; column < i.Bitmap.Width; column++)
{
for (int row = 0; row < i.Bitmap.Height; row++)
{
Color c1 = i.GetPixel(column, row);
Color c2 = i2.GetPixel(column, row);
red[column, row] = c2.R - c1.R;
blue[column, row] = c2.B - c1.B;
green[column, row] = c2.G - c1.G;
if (red[column, row] > redMax) redMax = red[column, row];
if (red[column, row] < redMin) redMin = red[column, row];
if (blue[column, row] > blueMax) blueMax = blue[column, row];
if (blue[column, row] < blueMin) blueMin = blue[column, row];
if (green[column, row] > greenMax) greenMax = green[column, row];
if (green[column, row] < greenMin) greenMin = green[column, row];
}
}
//find the range of the min an max
redRange = Math.Abs(redMax - redMin);
blueRange = Math.Abs(blueMax - blueMin);
greenRange = Math.Abs(greenRange - greenMin);
//Normalize the values in the arrays and load the result image
for (int column = 0; column < i.Bitmap.Width; column++)
{
for (int row = 0; row < i.Bitmap.Height; row++)
{
if (redRange != 0)
red[column, row] = 255 - (((redMax - red[column, row]) * 255) / redRange);
if (blueRange != 0)
blue[column, row] = 255 - (((blueMax - blue[column, row]) * 255) / blueRange);
if (greenRange != 0)
green[column, row] = 255 - (((greenMax - green[column, row]) * 255) / greenRange);
if (red[column, row] < 0)
red[column, row] = 0;
if (blue[column, row] < 0)
blue[column, row] = 0;
if (green[column, row] < 0)
green[column, row] = 0;
i2.SetPixel(column, row, Color.FromArgb(red[column, row], green[column, row],
blue[column, row]));
}
}
i.UnlockBitmap();
i2.UnlockBitmap();
return i2.Bitmap.Clone() as Bitmap;
}
/// <summary>
/// Get the red pixels from the bitmap
/// </summary>
/// <param name="b">Image to Process</param>
/// <returns>Filtered Image</returns>
public static Bitmap GetRedBitmap(Bitmap b)
{
ImagerBitmap i = new ImagerBitmap(b.Clone() as Bitmap);
for (int column = 0; column < i.Bitmap.Width; column++)
{
for (int row = 0; row < i.Bitmap.Height; row++)
{
i.SetPixel(column, row, Color.FromArgb(i.GetPixel(column, row).R, 0, 0));
}
}
i.UnlockBitmap();
return i.Bitmap.Clone() as Bitmap;
}
/// <summary>
/// Make the image black and white
/// </summary>
/// <param name="b">Image to Process</param>
/// <returns>Filtered Image</returns>
public static Bitmap GetBlackAndWhiteBitmap(Bitmap b)
{
ImagerBitmap i = new ImagerBitmap(b.Clone() as Bitmap);
double[] histogram = new double[256];
for (int column = 0; column < i.Bitmap.Width; column++)
{
for (int row = 0; row < i.Bitmap.Height; row++)
{
histogram[i.GetGreyPixel(column, row)]++;
}
}
//find the position of the max value on the left
int leftK = 0;
for (int k = 0; k < 128; k++)
{
if (histogram[k] > histogram[leftK]) leftK = k;
}
//find the position of the max value on the right
int rightK = 0;
for (int k = 128; k < 256; k++)
{
if (histogram[k] > histogram[rightK]) rightK = k;
}
//find the min value between the 2 local maxes
int localMin = rightK;
for (int k = leftK; k < rightK; k++)
{
if (histogram[k] < histogram[localMin]) localMin = k;
}
for (int column = 0; column < i.Bitmap.Width; column++)
{
for (int row = 0; row < i.Bitmap.Height; row++)
{
int val = (i.GetPixel(column, row).R + i.GetPixel(column, row).G
+ i.GetPixel(column, row).B) / 3;
if (val > localMin)
val = 255;
else
val = 0;
i.SetPixel(column, row, Color.FromArgb(val, val, val));
}
}
i.UnlockBitmap();
return i.Bitmap.Clone() as Bitmap;
}
public static Bitmap GetBlackAndWhiteBitmap2(Bitmap b)
{
ImagerBitmap i = new ImagerBitmap(b.Clone() as Bitmap);
double[] histogram = new double[256];
for (int column = 0; column < i.Bitmap.Width; column++)
{
for (int row = 0; row < i.Bitmap.Height; row++)
{
histogram[i.GetGreyPixel(column, row)]++;
}
}
double k = b.Width * b.Height;
double half = k / 2;
int middle = 0;
while (k > half)
{
k = k - histogram[middle];
middle++;
}
for (int column = 0; column < i.Bitmap.Width; column++)
{
for (int row = 0; row < i.Bitmap.Height; row++)
{
int val = (i.GetPixel(column, row).R + i.GetPixel(column, row).G
+ i.GetPixel(column, row).B) / 3;
if (val > middle)
val = 255;
else
val = 0;
i.SetPixel(column, row, Color.FromArgb(val, val, val));
}
}
i.UnlockBitmap();
return i.Bitmap.Clone() as Bitmap;
}
public static void GenerateExcelFile(Bitmap b)
{
ImagerBitmap i = new ImagerBitmap(b.Clone() as Bitmap);
string fileName = "output.txt";
int f = 0;
using (StreamWriter sw = new StreamWriter(fileName, false))
{
sw.WriteLine("{0}\t{1}\t{2}\t{3}\t{4}\t{5}\t{6}", "Index", "Row", "Column", "Red",
"Green", "Blue", "Gray");
for (int column = 0; column < i.Bitmap.Width; column++)
{
for (int row = 0; row < i.Bitmap.Height; row++)
{
f++;
Color c = i.GetPixel(column, row);
int g = i.GetGreyPixel(column, row);
sw.WriteLine("{0}\t{1}\t{2}\t{3}\t{4}\t{5}\t{6}", f,
row, column, c.R, c.G, c.B, g);
}
}
}
i.UnlockBitmap();
System.Diagnostics.Process.Start(fileName);
}
