public static Image getJpgThumbnailFromNEF(string filename)
{
byte[] imgData = extractJpegFromRaw(filename);
if (imgData != null)
{
MemoryStream stream = new MemoryStream();
stream.Write(imgData, 0, imgData.Length);
Image myImage = Image.FromStream(stream);
Bitmap resizedImage = ResizeImage(myImage, THUMB_WIDTH, THUMB_HEIGHT);
Rectangle rect = new Rectangle(0, 0, resizedImage.Width, resizedImage.Height);
System.Drawing.Imaging.BitmapData bmpData =
resizedImage.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,
resizedImage.PixelFormat);
IntPtr ptr = bmpData.Scan0;
int bytes = Math.Abs(bmpData.Stride) * resizedImage.Height;
byte[] rgbValues = new byte[bytes];
System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes);
// Find min max values
byte min = 0xFF;
byte max = 0;
int[] totalLumin = new int[] { 0, 0, 0 };
for (int i = 0; i < bytes; i += 4)
{
if (rgbValues[i] < min)
{
min = rgbValues[i];
}
if (rgbValues[i] > max)
{
max = rgbValues[i];
}
if (rgbValues[i + 1] < min)
{
min = rgbValues[i + 1];
}
if (rgbValues[i + 1] > max)
{
max = rgbValues[i + 1];
}
if (rgbValues[i + 1] < min)
{
min = rgbValues[i + 1];
}
if (rgbValues[i + 1] > max)
{
max = rgbValues[i + 1];
}
totalLumin[0] += (int)rgbValues[i + 0];
totalLumin[1] += (int)rgbValues[i + 1];
totalLumin[2] += (int)rgbValues[i + 2];
}
for (int i = 0; i < 3; i++)
{
totalLumin[i] /= (bytes / 4);
}
int totalAverage = (totalLumin[0] + totalLumin[1] + totalLumin[2]) / 3;
float grayContrastFactor = 127.0f / (float)totalAverage;
byte[] contrastLUT = new byte[256];
for (int i = 0; i < totalAverage; i++)
{
contrastLUT[i] = (byte)((float)i * (grayContrastFactor * (float)i / (float)totalAverage + 1.0f * (float)(totalAverage - i) / totalAverage));
}
for (int i = totalAverage; i < 256; i++)
{
contrastLUT[i] = (byte)((float)i * (grayContrastFactor * (float)(255 - i) / (float)(255 - totalAverage) + 1.0f * (float)(i - totalAverage) / (float)(255 - totalAverage)));
}
// Perform level adjustment
float r, g, b, h, s, v;
for (int i = 0; i < bytes; i += 4)
{
//if ((i % 2400) < 1200)
{
r = (float)rgbValues[i + 0] / 255.0f;
g = (float)rgbValues[i + 1] / 255.0f;
b = (float)rgbValues[i + 2] / 255.0f;
ImageProcessing.RGBtoHSV(r, g, b, out h, out s, out v);
v = (v * grayContrastFactor > 1.0f ? 1.0f : (v * grayContrastFactor));
ImageProcessing.HSVtoRGB(out r, out g, out b, h, s, v);
rgbValues[i + 0] = (byte)(r * 255.0f);
rgbValues[i + 1] = (byte)(g * 255.0f);
rgbValues[i + 2] = (byte)(b * 255.0f);
}
}
// Copy the RGB values back to the bitmap
System.Runtime.InteropServices.Marshal.Copy(rgbValues, 0, ptr, bytes);
resizedImage.UnlockBits(bmpData);
return(resizedImage);
}
else
{
return(null);
}
}
