public static Bitmap EdgeDetectConvolution(Bitmap b, short nType, byte nThreshold)
{
Tilt_Correction_Process m = new Tilt_Correction_Process();
// I need to make a copy of this bitmap BEFORE I alter it 80)
Bitmap bTemp = (Bitmap)b.Clone();
switch (nType)
{
case EDGE_DETECT_SOBEL:
m.SetAll(0);
m.TopLeft = m.BottomLeft = 1;
m.TopRight = m.BottomRight = -1;
m.MidLeft = 2;
m.MidRight = -2;
m.Offset = 0;
break;
case EDGE_DETECT_PREWITT:
m.SetAll(0);
m.TopLeft = m.MidLeft = m.BottomLeft = -1;
m.TopRight = m.MidRight = m.BottomRight = 1;
m.Offset = 0;
break;
case EDGE_DETECT_KIRSH:
m.SetAll(-3);
m.Pixel = 0;
m.TopLeft = m.MidLeft = m.BottomLeft = 5;
m.Offset = 0;
break;
}
Tilt_Correction_Process.Conv3x3(b, m);
switch (nType)
{
case EDGE_DETECT_SOBEL:
m.SetAll(0);
m.TopLeft = m.TopRight = 1;
m.BottomLeft = m.BottomRight = -1;
m.TopMid = 2;
m.BottomMid = -2;
m.Offset = 0;
break;
case EDGE_DETECT_PREWITT:
m.SetAll(0);
m.BottomLeft = m.BottomMid = m.BottomRight = -1;
m.TopLeft = m.TopMid = m.TopRight = 1;
m.Offset = 0;
break;
case EDGE_DETECT_KIRSH:
m.SetAll(-3);
m.Pixel = 0;
m.BottomLeft = m.BottomMid = m.BottomRight = 5;
m.Offset = 0;
break;
}
Tilt_Correction_Process.Conv3x3(bTemp, m);
BitmapData bmData = b.LockBits(new Rectangle(0, 0, b.Width, b.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
BitmapData bmData2 = bTemp.LockBits(new Rectangle(0, 0, b.Width, b.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
int stride = bmData.Stride;
System.IntPtr Scan0 = bmData.Scan0;
System.IntPtr Scan02 = bmData2.Scan0;
unsafe
{
byte* p = (byte*)(void*)Scan0;
byte* p2 = (byte*)(void*)Scan02;
int nOffset = stride - b.Width * 3;
int nWidth = b.Width * 3;
int nPixel = 0;
for (int y = 0; y < b.Height; ++y)
{
for (int x = 0; x < nWidth; ++x)
{
nPixel = (int)Math.Sqrt((p[0] * p[0]) + (p2[0] * p2[0]));
if (nPixel < nThreshold) nPixel = nThreshold;
if (nPixel > 255) nPixel = 255;
p[0] = (byte)nPixel;
++p;
++p2;
}
p += nOffset;
p2 += nOffset;
}
}
b.UnlockBits(bmData);
bTemp.UnlockBits(bmData2);
return b;
}
public static bool GaussianBlur(Bitmap b, int nWeight /* default to 4*/)
{
Tilt_Correction_Process m = new Tilt_Correction_Process();
m.SetAll(1);
m.Pixel = nWeight;
m.TopMid = m.MidLeft = m.MidRight = m.BottomMid = 2;
m.Factor = nWeight + 12;
return Tilt_Correction_Process.Conv3x3(b, m);
}
public static bool Conv3x3(Bitmap b, Tilt_Correction_Process m)
{
// Avoid divide by zero errors
if (0 == m.Factor) return false;
Bitmap bSrc = (Bitmap)b.Clone();
BitmapData bmData = b.LockBits(new Rectangle(0, 0, b.Width, b.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
BitmapData bmSrc = bSrc.LockBits(new Rectangle(0, 0, bSrc.Width, bSrc.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
int stride = bmData.Stride;
int stride2 = stride * 2;
System.IntPtr Scan0 = bmData.Scan0;
System.IntPtr SrcScan0 = bmSrc.Scan0;
unsafe
{
byte* p = (byte*)(void*)Scan0;
byte* pSrc = (byte*)(void*)SrcScan0;
int nOffset = stride - b.Width * 3;
int nWidth = b.Width - 2;
int nHeight = b.Height - 2;
int nPixel;
for (int y = 0; y < nHeight; ++y)
{
for (int x = 0; x < nWidth; ++x)
{
nPixel = ((((pSrc[2] * m.TopLeft) + (pSrc[5] * m.TopMid) + (pSrc[8] * m.TopRight) +
(pSrc[2 + stride] * m.MidLeft) + (pSrc[5 + stride] * m.Pixel) + (pSrc[8 + stride] * m.MidRight) +
(pSrc[2 + stride2] * m.BottomLeft) + (pSrc[5 + stride2] * m.BottomMid) + (pSrc[8 + stride2] * m.BottomRight)) / m.Factor) + m.Offset);
if (nPixel < 0) nPixel = 0;
if (nPixel > 255) nPixel = 255;
p[5 + stride] = (byte)nPixel;
nPixel = ((((pSrc[1] * m.TopLeft) + (pSrc[4] * m.TopMid) + (pSrc[7] * m.TopRight) +
(pSrc[1 + stride] * m.MidLeft) + (pSrc[4 + stride] * m.Pixel) + (pSrc[7 + stride] * m.MidRight) +
(pSrc[1 + stride2] * m.BottomLeft) + (pSrc[4 + stride2] * m.BottomMid) + (pSrc[7 + stride2] * m.BottomRight)) / m.Factor) + m.Offset);
if (nPixel < 0) nPixel = 0;
if (nPixel > 255) nPixel = 255;
p[4 + stride] = (byte)nPixel;
nPixel = ((((pSrc[0] * m.TopLeft) + (pSrc[3] * m.TopMid) + (pSrc[6] * m.TopRight) +
(pSrc[0 + stride] * m.MidLeft) + (pSrc[3 + stride] * m.Pixel) + (pSrc[6 + stride] * m.MidRight) +
(pSrc[0 + stride2] * m.BottomLeft) + (pSrc[3 + stride2] * m.BottomMid) + (pSrc[6 + stride2] * m.BottomRight)) / m.Factor) + m.Offset);
if (nPixel < 0) nPixel = 0;
if (nPixel > 255) nPixel = 255;
p[3 + stride] = (byte)nPixel;
p += 3;
pSrc += 3;
}
p += nOffset;
pSrc += nOffset;
}
}
b.UnlockBits(bmData);
bSrc.UnlockBits(bmSrc);
return true;
}
