[函数名称]
噪声函数WriteableBitmap NoiseProcess(WriteableBitmap src, byte flagNoise, double meanValue, double varianceValue)
/// <summary>
/// Noise process.
/// </summary>
/// <param name="src">The source image.</param>
/// <param name="flagNoise">One parameter to choose noise mode,0--Gauss noise,1--Rayleigh noise,2--Noise index,3--alt and pepper noise.</param>
/// <param name="meanValue">Mean value or alt value.</param>
/// <param name="varianceValue">Variance value or pepper value.</param>
/// <returns></returns>
public static WriteableBitmap NoiseProcess(WriteableBitmap src, byte flagNoise, double meanValue, double varianceValue)////噪声
{
if (src != null)
{
int w = src.PixelWidth;
int h = src.PixelHeight;
WriteableBitmap srcImage = new WriteableBitmap(w, h);
byte[] temp = src.PixelBuffer.ToArray();
double tempValue = 0;
Random r1, r2;
double v1 = 0, v2 = 0;
r1 = new Random(unchecked((int)DateTime.Now.Ticks));
r2 = new Random(~unchecked((int)DateTime.Now.Ticks));
for (int i = 0; i < temp.Length; i++)
{
switch (flagNoise)
{
case 0:
//Gauss noise 0 20
do
{
v1 = r1.NextDouble();
}
while (v1 <= 0.00000000001);
v2 = r2.NextDouble();
tempValue = Math.Sqrt(-2 * Math.Log(v1)) * Math.Cos(2 * Math.PI * v2) * varianceValue + meanValue;
break;
case 1:
do
//Rayleigh noise 0 200
{
v1 = r1.NextDouble();
}
while (v1 >= 0.9999999999);
tempValue = meanValue + Math.Sqrt(-1 * varianceValue * Math.Log(1 - v1));
break;
case 2:
//Noise index 0.1
do
{
v1 = r1.NextDouble();
}
while (v1 >= 0.9999999999);
tempValue = -1 * Math.Log(1 - v1) / meanValue;
break;
case 3:
//Salt and pepper noise 0.02 0.02
v1 = r1.NextDouble();
if (v1 <= meanValue)
tempValue = -500;
else if (v1 >= (1 - varianceValue))
tempValue = 500;
else
tempValue = 0;
break;
default:
break;
}
tempValue = tempValue + temp[i];
if (tempValue > 255)
{
temp[i] = 255;
}
else if (tempValue < 0)
{
temp[i] = 0;
}
else
temp[i] = Convert.ToByte(tempValue);
}
Stream sTemp = srcImage.PixelBuffer.AsStream();
sTemp.Seek(0, SeekOrigin.Begin);
sTemp.Write(temp, 0, w * 4 * h);
return srcImage;
}
else
{
return null;
}
}
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