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MUST Corp.

MUST Corp.

www.must.or.kr

 Microsoft CERTIFIED Partner Software Development, Web Development, Data Platform

 Microsoft Small Business Specialist

MCSD

Microsoft Certified IT Professional

Microsoft Certified Professional Developer

Arithmetic mean filter

Gaussian Noise

Image

Salt-and-Pepper Noise

Image

Gaussian Noise & Salt-and-Pepper Noise

Image

Code

public override Bitmap Process(Bitmap input)
{
	if (input.PixelFormat != PixelFormat.Format8bppIndexed)
		throw new NotSupportedException();

	Bitmap output = (Bitmap)input.Clone();

	int rm = M / 2;
	int rn = N / 2;

	int width = output.Width;
	int height = output.Height;

	int mn = M * N;

	BitmapData inputData = input.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format8bppIndexed);
	BitmapData outputData = output.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format8bppIndexed);

	unsafe
	{
		byte* inputPtr = (byte*)inputData.Scan0.ToPointer();
		byte* outputPtr = (byte*)outputData.Scan0.ToPointer();

		for (int i = 0; i < width * height; i++)
		{
			int x = i % width;
			int y = i / width;

			if (x >= rm && y >= rn && x < width - rm && y < height - rn)
			{
				int sum = 0;
				for (int tx = -rm; tx <= rm; tx++)
					for (int ty = -rn; ty <= rn; ty++)
					{
						sum += inputPtr[i + tx + ty * width];
					}
				outputPtr[i] = (byte)(sum / mn);
			}
		}
	}

	output.UnlockBits(outputData);
	input.UnlockBits(inputData);

	return output;
}




Median filter

Gaussian Noise

Image

Salt-and-Pepper Noise

Image

Gaussian Noise & Salt-and-Pepper Noise

Image

Code

public override Bitmap Process(Bitmap input)
{
	if (input.PixelFormat != PixelFormat.Format8bppIndexed)
		throw new NotSupportedException();

	Bitmap output = (Bitmap)input.Clone();

	int rm = M / 2;
	int rn = N / 2;

	int width = output.Width;
	int height = output.Height;

	int mn = M * N;

	BitmapData inputData = input.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format8bppIndexed);
	BitmapData outputData = output.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format8bppIndexed);

	unsafe
	{
		byte* inputPtr = (byte*)inputData.Scan0.ToPointer();
		byte* outputPtr = (byte*)outputData.Scan0.ToPointer();

		for (int i = 0; i < width * height; i++)
		{
			int x = i % width;
			int y = i / width;

			if (x >= rm && y >= rn && x < width - rm && y < height - rn)
			{
				List<byte> sequence = new List<byte>(mn);
				for (int tx = -rm; tx <= rm; tx++)
					for (int ty = -rn; ty <= rn; ty++)
					{
						sequence.Add(inputPtr[i + tx + ty * width]);
					}
				sequence.Sort();
				outputPtr[i] = sequence[mn / 2];
			}
		}
	}

	output.UnlockBits(outputData);
	input.UnlockBits(inputData);

	return output;
}





Adaptive, local noise reduction filter

Gaussian Noise

Image

Salt-and-Pepper Noise

Image

Gaussian Noise & Salt-and-Pepper Noise

Image

Code

public override Bitmap Process(Bitmap input)
{
	if (input.PixelFormat != PixelFormat.Format8bppIndexed)
		throw new NotSupportedException();

	Bitmap output = (Bitmap)input.Clone();

	int rm = M / 2;
	int rn = N / 2;

	int width = output.Width;
	int height = output.Height;

	int mn = M * N;

	BitmapData inputData = input.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format8bppIndexed);
	BitmapData outputData = output.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format8bppIndexed);

	unsafe
	{
		byte* inputPtr = (byte*)inputData.Scan0.ToPointer();
		byte* outputPtr = (byte*)outputData.Scan0.ToPointer();

		for (int i = 0; i < width * height; i++)
		{
			int x = i % width;
			int y = i / width;

			if (x >= rm && y >= rn && x < width - rm && y < height - rn)
			{
				double mL = 0; // mean
				List<byte> sequence = new List<byte>(mn);
				for (int tx = -rm; tx <= rm; tx++)
					for (int ty = -rn; ty <= rn; ty++)
					{
						sequence.Add(inputPtr[i + tx + ty * width]);
						mL += inputPtr[i + tx + ty * width];
					}
				mL /= mn;

				double σL2 = 0;
				foreach (byte pixel in sequence)
				{
					σL2 += Math.Pow(mL - pixel, 2);
				}
				σL2 /= mn;

				double gxy = inputPtr[i];

				outputPtr[i] = (byte)(gxy - Math.Min(1.0, _ση2 / σL2) * (gxy - mL));
			}
		}
	}

	output.UnlockBits(outputData);
	input.UnlockBits(inputData);

	return output;
}





Adaptive median filter

Gaussian Noise

Image

Salt-and-Pepper Noise

Image

Gaussian Noise & Salt-and-Pepper Noise

Image

Code

public Bitmap Process(Bitmap input)
{
	if (input.PixelFormat != PixelFormat.Format8bppIndexed)
		throw new NotSupportedException();

	Bitmap output = (Bitmap)input.Clone();

	int width = output.Width;
	int height = output.Height;

	int scurr = 3;
	int smax_local = 3;


	BitmapData inputData = input.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format8bppIndexed);
	BitmapData outputData = output.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format8bppIndexed);

	unsafe
	{
		byte* inputPtr = (byte*)inputData.Scan0.ToPointer();
		byte* outputPtr = (byte*)outputData.Scan0.ToPointer();

		for (int i = 0; i < width * height; i++)
		{
			int x = i % width;
			int y = i / width;

			if (x >= 1 && y >= 1 && x < width - 1 && y < height - 1) // minimum 3x3 area
			{
				scurr = 3;

				// if we are close to border, we cannot go beyond it
				smax_local = Math.Min(x * 2 + 1, Smax);
				smax_local = Math.Min(y * 2 + 1, smax_local);
				smax_local = Math.Min((width - 1 - x) * 2 + 1, smax_local);
				smax_local = Math.Min((height - 1 - y) * 2 + 1, smax_local);

				do
				{
					int rm = scurr / 2;
					int rn = scurr / 2;
					int mn = scurr * scurr;

					List<byte> sequence = new List<byte>(mn);
					for (int tx = -rm; tx <= rm; tx++)
						for (int ty = -rn; ty <= rn; ty++)
						{
							sequence.Add(inputPtr[i + tx + ty * width]);
						}
					sequence.Sort();

					byte zmin = sequence[0];
					byte zmax = sequence[mn - 1];
					byte zmed = sequence[mn / 2];
					byte zxy = inputPtr[i];

					int A1 = zmed - zmin;
					int A2 = zmed - zmax;
					if (A1 > 0 && A2 < 0)
					{
						int B1 = zxy - zmin;
						int B2 = zxy - zmax;
						if (B1 > 0 && B2 < 0)
						{
							outputPtr[i] = zxy;
							break;
						}
						else
						{
							outputPtr[i] = zmed;
							break;
						}
					}
					else
					{
						scurr += 2;
						if (scurr > smax_local)
						{
							outputPtr[i] = zmed;
							break;
						}
					}
				} while (true);
			}
		}
	}

	output.UnlockBits(outputData);
	input.UnlockBits(inputData);

	return output;
}

MUST Creative Engineering Laboratory

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Copyright © 2010 MUST Corp. All rights reserved. must@must.or.kr
This Program is released under the GNU General Public License v2. View the GNU General Public License v2 or visit the GNU website.