internal static HistoRaw CalculateHistogram(ImageComponent <int> image)
{
var maxValue = 1 << image.ColorDepth;
HistoRaw histogram = new HistoRaw()
{
luma = new int[maxValue],
red = new int[maxValue],
blue = new int[maxValue],
green = new int[maxValue]
};
for (int y = 0; y < image.dim.height; y++)
{
long realY = (y + image.offset.height) * image.UncroppedDim.width;
for (int x = 0; x < image.dim.width; x++)
{
long realPix = realY + x + image.offset.width;
histogram.luma[(int)(0.299 * image.red[realPix] + 0.587 * image.green[realPix] + 0.114 * image.blue[realPix])]++;
histogram.red[image.red[realPix]]++;
histogram.green[image.green[realPix]]++;
histogram.blue[image.blue[realPix]]++;
}
}
return(histogram);
}
internal static void HistogramEqualisation(ImageComponent <int> image, HistoRaw histogram)
{
//TODO change and correct
//apply histogram equalisation if needed using the histogram
//create a lookup table
var lut = new int[uint.MaxValue];
double pixelCount = image.dim.height * image.dim.width;
int sum = 0;
// build a LUT containing scale factor
for (int i = 0; i < lut.Length; ++i)
{
sum += histogram.luma[i];
lut[i] = (int)(sum * 255 / pixelCount);
}
// transform image using sum histogram as a LUT
Parallel.For(0, image.dim.height, y =>
{
long realY = y * image.dim.width;
for (int x = 0; x < image.dim.width; x++)
{
long realX = realY + x;
image.red[realX] = lut[image.red[realX]];
image.green[realX] = lut[image.green[realX]];
image.blue[realX] = lut[image.blue[realX]];
}
});
}
public unsafe HistoRaw ApplyTo16Bits(ImageComponent <ushort> image, SoftwareBitmap bitmap, bool histogram)
{
Debug.Assert(bitmap.BitmapPixelFormat == BitmapPixelFormat.Rgba16);
var buffer = Apply(image);
//Clip the image
//Luminance.Clip(buffer, 16);
HistoRaw histo = null;
//calculate the new histogram (create a 8 bits histogram)
if (histogram)
{
histo = HistogramHelper.CalculateHistogram(buffer);
}
//copy the buffer to the image with clipping
//calculte the shift between colordepth input and output
int shift = image.ColorDepth - 16;
using (BitmapBuffer buff = bitmap.LockBuffer(BitmapBufferAccessMode.Write))
using (var reference = buff.CreateReference())
{
((IMemoryBufferByteAccess)reference).GetBuffer(out var temp, out uint capacity);
Parallel.For(0, buffer.dim.height, y =>
{
long realY = y * buffer.dim.width;
for (int x = 0; x < buffer.dim.width; x++)
{
long realPix = realY + x;
long bufferPix = realPix * 8;
temp[bufferPix] = (byte)(buffer.red[realPix] >> 8);
temp[bufferPix + 1] = (byte)(buffer.red[realPix]);
temp[bufferPix + 2] = (byte)(buffer.green[realPix] >> 8);
temp[bufferPix + 3] = (byte)(buffer.green[realPix]);
temp[bufferPix + 4] = (byte)(buffer.blue[realPix] >> 8);
temp[bufferPix + 5] = (byte)(buffer.blue[realPix]);
temp[bufferPix + 6] = 255; //set transparency to 255 else image will be blank
temp[bufferPix + 7] = 255; //set transparency to 255 else image will be blank
}
});
}
return(histo);
}
public unsafe HistoRaw ApplyTo8Bits(ImageComponent <ushort> image, SoftwareBitmap bitmap, bool histogram)
{
Debug.Assert(image.red != null);
Debug.Assert(image.blue != null);
Debug.Assert(image.green != null);
Debug.Assert(image.dim.Area >= 4);
Debug.Assert(bitmap != null);
Debug.Assert(image.dim.Area == bitmap.PixelHeight * bitmap.PixelWidth);
var buffer = Apply(image);
//Clip the image
Luminance.Clip(buffer, 8);
//calculate the new histogram (create a 8 bits histogram)
HistoRaw histo = null;
if (histogram)
{
histo = HistogramHelper.CalculateHistogram(buffer);
}
//copy the buffer to the image with clipping
using (BitmapBuffer buff = bitmap.LockBuffer(BitmapBufferAccessMode.Write))
using (var reference = buff.CreateReference())
{
((IMemoryBufferByteAccess)reference).GetBuffer(out var temp, out uint capacity);
Parallel.For(0, buffer.dim.height, y =>
{
long realY = y * buffer.dim.width;
for (int x = 0; x < buffer.dim.width; x++)
{
long realPix = realY + x;
long bufferPix = realPix * 4;
temp[bufferPix] = (byte)(buffer.blue[realPix]);
temp[bufferPix + 1] = (byte)(buffer.green[realPix]);
temp[bufferPix + 2] = (byte)(buffer.red[realPix]);
temp[bufferPix + 3] = 255; //set transparency to 255 else image will be blank
}
});
}
return(histo);
}
internal static HistoRaw CalculateLumaHistogram(ImageComponent <int> image)
{
HistoRaw histogram = new HistoRaw()
{
luma = new int[(1 << image.ColorDepth)]
};
for (int y = 0; y < image.dim.height; y++)
{
long realY = (y + image.offset.height) * image.UncroppedDim.width;
for (int x = 0; x < image.dim.width; x++)
{
long realPix = realY + x + image.offset.width;
histogram.luma[(int)((Math.Max(Math.Max(image.red[realPix], image.green[realPix]), image.blue[realPix])
+ Math.Min(Math.Min(image.red[realPix], image.green[realPix]), image.blue[realPix])) / 2.0)]++;
}
}
return(histogram);
}
