public byte[] GetStrongPictureData(string fileName)
{
byte[] bmpData = null;
if (File.Exists(fileName))
{
Bitmap bitmap = (Bitmap)(Image.FromFile(fileName));
int width = bitmap.Width; //长度像素值
int height = bitmap.Height; //高度像素值
Rectangle rect = new Rectangle(0, 0, width, height);
BitmapData bitmapData = bitmap.LockBits(rect, ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
IntPtr srcPtr = bitmapData.Scan0;
int bmpLength = bitmapData.Stride * height;
bmpData = new byte[bmpLength];
Marshal.Copy(srcPtr, bmpData, 0, bmpLength); //复制GRB信息到byte数组
bmpData = OnOutClean(width, height, bmpData);
Marshal.Copy(bmpData, 0, srcPtr, bmpData.Length); //复制回位图
bitmap.UnlockBits(bitmapData); //解锁位图
MemoryStream ms = new MemoryStream();
bitmap.Save(ms, bitmap.RawFormat);
ms.Flush();
bmpData = ms.GetBuffer();
ms.Close();
MemoryStream ms = new MemoryStream();
bitmap.Save(ms, bitmap.RawFormat);
ms.Flush();
bmpData = ms.GetBuffer();
ms.Close();
}
else
{
bmpData = null;
}
return bmpData;
}
public static void memset(byte[] buf, byte val, int size)
{
for (int i = 0; i < size; i++)
{
buf[i] = val;
}
}
public static byte[] OnOutClean(int width, int height, byte[] _old)
{
int x, y;
byte r, g, b;
byte[] rp = new byte[width * height];
byte[] gp = new byte[width * height];
byte[] bp = new byte[width * height];
byte[] _newRGB = new byte[3 * width * height];
memset(rp, 255, rp.Length);
memset(gp, 255, gp.Length);
memset(bp, 255, bp.Length);
memset(_newRGB, 255, _newRGB.Length);
for (y = 0; y < height; y++)
{
for (x = 0; x < width; x++)
{
b = _old[y * width * 3 + 3 * x + 0];
g = _old[y * width * 3 + 3 * x + 1];
r = _old[y * width * 3 + 3 * x + 2];
rp[y * width + x] = b;
gp[y * width + x] = g;
bp[y * width + x] = r;
}
}
int[] tol1 = new int[2];
int[] tol2 = new int[2];
int[] tol3 = new int[2];
tol1 = Low_High_Value(width, height, rp, 256);
tol2 = Low_High_Value(width, height, gp, 256);
tol3 = Low_High_Value(width, height, bp, 256);
ImgAdjust(width, height, tol1[0], tol1[1], 0.0, 1.0, rp, rp);
ImgAdjust(width, height, tol2[0], tol2[1], 0.0, 1.0, gp, gp);
ImgAdjust(width, height, tol3[0], tol3[1], 0.0, 1.0, bp, bp);
for (y = 0; y < height; y++)
{
for (x = 0; x < width; x++)
{
_newRGB[y * width * 3 + 3 * x + 0] = bp[y * width + x];
_newRGB[y * width * 3 + 3 * x + 1] = gp[y * width + x];
_newRGB[y * width * 3 + 3 * x + 2] = rp[y * width + x];
}
}
return _newRGB;
}
//图像对比度加强
public static int[] Low_High_Value(int width, int height, byte[] input, int count)
{
int i, x, y;
int sum = 0;
double bot = 0.0005;
double top = 0.9995;
int[] values = new int[2];
double[] his = new double[count];
double[] his_plus = new double[count];
for (x = 0; x < width; x++)
{
for (y = 0; y < height; y++)
{
int a = input[x + y * width];
his[a]++;
sum++;
}
}
his_plus[0] = his[0];
for (i = 1; i < count; i++)
{
his_plus[i] = his_plus[i - 1] + his[i];
}
for (i = 0; i < count; i++)
{
his_plus[i] = his_plus[i] / sum;
}
//双阀值
for (i = 0; i < count; i++)
{
if (his_plus[i] > bot)
{
values[0] = i;
break;
}
}
for (i = 0; i < count; i++)
{
if (his_plus[i] > top)
{
values[1] = i;
break;
}
}
return values;
}
public static void ImgAdjust(int width, int height, int lIn, int hIn, double lOut, double hOut, byte[] input, byte[] output)
{
double[] lpstr = new double[width * height];
double[] lut = new double[256];
double[] lut1 = new double[256];
int i = 0;
int x, y;
//门限值
double fmin = (double)lIn * 1.0 / 255;
double fmax = (double)hIn * 1.0 / 255;
//得到拉伸后的图像
for (i = 0; i < 256; i++)
{
lut[i] = i * 1.0 / 256;//像素为i的值对应的线性变化值
//确保像素点在[fmin,fmax]间
if (lut[i] > fmax)
lut[i] = fmax;
if (lut[i] > fmin)
{
lut1[i] = lut[i];
}
else
{
lut1[i] = fmin;
}
//图像拉伸，[fmin,fmax]拉伸到[0,1]
lut1[i] = (lut1[i] - fmin) / (fmax - fmin);
lut1[i] = lut1[i] * (hOut - lOut) + lOut;
}
for (x = 0; x < width; x++)
{
for (y = 0; y < height; y++)
{
lpstr[x + y * width] = lut1[input[x + y * width]] * 255;
output[x + y * width] = (byte)lpstr[x + y * width];
}
}
}