public static Kernel1D CreateGaussianDerivative(double standardDeviation, int order, double norm)
{
Kernel1D k = new Kernel1D();
k.InitGaussianDerivative(standardDeviation, order, norm);
return(k);
}
public static Kernel1D CreateGaussian(double standardDeviation)
{
Kernel1D k = new Kernel1D();
k.InitGaussian(standardDeviation);
return(k);
}
public static void GaussianSmooth(IImage <double> source, IImage <double> target, double scale)
{
Kernel1D smooth = Kernel1D.CreateGaussian(scale);
IImage <double> tempor = source.CloneSize();
SeparableConvolveX(source, tempor, smooth);
SeparableConvolveY(tempor, target, smooth);
}
public static void GaussianGradient(IImage <double> source, IImage <double> targetX, IImage <double> targetY, double scale)
{
Kernel1D smooth = Kernel1D.CreateGaussian(scale);
Kernel1D grad = Kernel1D.CreateGaussianDerivative(scale, 1);
IImage <double> tempor = source.CloneSize();
SeparableConvolveX(source, tempor, grad);
SeparableConvolveY(tempor, targetX, smooth);
SeparableConvolveX(source, tempor, smooth);
SeparableConvolveY(tempor, targetY, grad);
}
private static double ConvolvePixel <Iterator>(Iterator iSource, Kernel1D kernel, int kernelIndex)
where Iterator : IImageIterator <double>
{
double sum = 0.0;
Iterator iSampleSource = (Iterator)iSource.Offset(-kernel.Right);
Iterator iSampleSourceEnd = (Iterator)iSource.Offset(1 - kernel.Left);
while (!iSampleSource.Equals(iSampleSourceEnd))
{
sum += kernel[kernelIndex] * iSampleSource.Current;
--kernelIndex;
iSampleSource.MoveNext();
}
return(sum);
}
public static void HessianMatrixOfGaussian(IImage <double> source, IImage <double> targetXX, IImage <double> targetYY, IImage <double> targetXY, double scale)
{
Kernel1D smooth = Kernel1D.CreateGaussian(scale);
Kernel1D deriv1 = Kernel1D.CreateGaussianDerivative(scale, 1);
Kernel1D deriv2 = Kernel1D.CreateGaussianDerivative(scale, 2);
IImage <double> tempor = source.CloneSize();
SeparableConvolveX(source, tempor, deriv2);
SeparableConvolveY(tempor, targetXX, smooth);
SeparableConvolveX(source, tempor, smooth);
SeparableConvolveY(tempor, targetYY, deriv2);
SeparableConvolveX(source, tempor, deriv1);
SeparableConvolveY(tempor, targetXY, deriv1);
}
private static void ConvolveLine <Iterator>(Iterator iSource, Iterator iSourceEnd, Iterator iTarget, Kernel1D kernel)
where Iterator : IImageIterator <double>
{
Debug.Assert(kernel.Left <= 0);
Debug.Assert(kernel.Right >= 0);
int w = iSourceEnd.Difference(iSource);
Debug.Assert(w >= kernel.Right - kernel.Left + 1);
switch (kernel.BorderTreatment)
{
case BorderTreatmentMode.BorderTreatmentRepeat:
ConvolveLineRepeat(iSource, iSourceEnd, iTarget, kernel);
break;
case BorderTreatmentMode.BorderTreatmentClip:
double norm = 0.0;
for (int i = kernel.Left; i <= kernel.Right; ++i)
{
norm += kernel[i];
}
ConvolveLineClip(iSource, iSourceEnd, iTarget, kernel, norm);
break;
}
}
/// <summary>
/// Performs a one dimensional convolution in the y direction
/// </summary>
/// <param name="source"></param>
/// <param name="target"></param>
/// <param name="kernel"></param>
private static void SeparableConvolveY(IImage <double> source, IImage <double> target, Kernel1D kernel)
{
Debug.Assert(kernel.Left <= 0);
Debug.Assert(kernel.Right >= 0);
int w = source.Width;
int h = source.Height;
Debug.Assert(h >= kernel.Right - kernel.Left + 1, "Kernel cannot be longer than line");
for (int x = 0; x < w; ++x)
{
ImageColumnIterator <double> cs = source.GetColumnIterator(x, 0);
ImageColumnIterator <double> csEnd = source.GetColumnIterator(x, source.Height);
ImageColumnIterator <double> ct = target.GetColumnIterator(x);
ConvolveLine(cs, csEnd, ct, kernel);
}
}
/// <summary>
/// Performs a one dimensional convolution in the x direction
/// </summary>
/// <param name="source"></param>
/// <param name="target"></param>
/// <param name="kernel"></param>
private static void SeparableConvolveX(IImage <double> source, IImage <double> target, Kernel1D kernel)
{
Debug.Assert(kernel.Left <= 0);
Debug.Assert(kernel.Right >= 0);
int w = source.Width;
int h = source.Height;
Debug.Assert(w >= kernel.Right - kernel.Left + 1, "Kernel cannot be longer than line");
for (int y = 0; y < h; ++y)
{
ImageRowIterator <double> rs = source.GetRowIterator(y);
ImageRowIterator <double> rsEnd = source.GetRowIterator(source.Width, y);
ImageRowIterator <double> rt = target.GetRowIterator(y);
ConvolveLine(rs, rsEnd, rt, kernel);
}
}
private static void ConvolveLineRepeat <Iterator>(Iterator iSource, Iterator iSourceEnd, Iterator iTarget, Kernel1D kernel)
where Iterator : IImageIterator <double>
{
int w = iSourceEnd.Difference(iSource);
Iterator iBegin = iSource;
for (int x = 0; x < w; ++x)
{
// Convolve each pixel
int kernelIndex = kernel.Right;
double sum = 0.0;
if (x < kernel.Right)
{
int x0 = x - kernel.Right;
Iterator iSampleSource = iBegin;
while (x0 != 0)
{
sum += kernel[kernelIndex] * iSampleSource.Current;
--kernelIndex;
++x0;
}
Iterator iSampleSourceEnd = (Iterator)iSource.Offset(1 - kernel.Left);
while (!iSampleSource.Equals(iSampleSourceEnd))
{
sum += kernel[kernelIndex] * iSampleSource.Current;
--kernelIndex;
iSampleSource.MoveNext();
}
}
else if (w - x <= -kernel.Left)
{
Iterator iSampleSource = (Iterator)iSource.Offset(-kernel.Right);
Iterator iSampleSourceEnd = iSourceEnd;
while (!iSampleSource.Equals(iSampleSourceEnd))
{
sum += kernel[kernelIndex] * iSampleSource.Current;
--kernelIndex;
iSampleSource.MoveNext();
}
int x0 = -kernel.Left - w + x + 1;
iSampleSource = (Iterator)iSourceEnd.Offset(-1);
while (x0 != 0)
{
sum += kernel[kernelIndex] * iSampleSource.Current;
--kernelIndex;
--x0;
}
}
else
{
sum += ConvolvePixel(iSource, kernel, kernelIndex);
}
iTarget.Current = sum;
iSource.MoveNext();
iTarget.MoveNext();
}
}
private static void ConvolveLineClip <Iterator>(Iterator iSource, Iterator iSourceEnd, Iterator iTarget, Kernel1D kernel, double norm)
where Iterator : IImageIterator <double>
{
// TODO: Our iterators should have the similar semantics to IEnumerator. i.e. They should
// start _before_ the collection to be iterated.
int w = iSourceEnd.Difference(iSource);
Iterator iBegin = iSource;
for (int x = 0; x < w; ++x)
{
// Convolve each pixel
int kernelIndex = kernel.Right;
double sum = 0.0;
if (x < kernel.Right)
{
int x0 = x - kernel.Right;
double clipped = 0.0;
while (x0 != 0)
{
clipped += kernel[kernelIndex];
--kernelIndex;
++x0;
}
Iterator iSampleSource = iBegin;
Iterator iSampleSourceEnd = (Iterator)iSource.Offset(1 - kernel.Left);
while (!iSampleSource.Equals(iSampleSourceEnd))
{
sum += kernel[kernelIndex] * iSampleSource.Current;
--kernelIndex;
iSampleSource.MoveNext();
}
sum = norm / (norm - clipped) * sum;
}
else if (w - x <= -kernel.Left)
{
Iterator iSampleSource = (Iterator)iSource.Offset(-kernel.Right);
Iterator iSampleSourceEnd = iSourceEnd;
while (!iSampleSource.Equals(iSampleSourceEnd))
{
sum += kernel[kernelIndex] * iSampleSource.Current;
--kernelIndex;
iSampleSource.MoveNext();
}
double clipped = 0.0;
int x0 = -kernel.Left - w + x + 1;
while (x0 != 0)
{
clipped += kernel[kernelIndex];
--kernelIndex;
--x0;
}
sum = norm / (norm - clipped) * sum;
}
else
{
sum += ConvolvePixel(iSource, kernel, kernelIndex);
}
iTarget.Current = sum;
iSource.MoveNext();
iTarget.MoveNext();
}
}