/// <summary>
/// x-direction convolute with an 1D double kernel
/// mirror expand source matrix before convolution
/// </summary>
/// <param name="kernel">1D double kernel</param>
/// <returns></returns>
private PZMath_matrix ConvoluteRowMirrorExpand(PZMath_vector kernel)
{
// kernel info
int kernelSize = kernel.Size;
int halfKernelSize = (kernelSize - 1) / 2;
// matrix info
int height = row;
int width = col;
// expand src matrix
PZMath_matrix expandSrc = this.BoundMirrorExpand(kernelSize, kernelSize);
PZMath_matrix expandDst = new PZMath_matrix(expandSrc);
// spatial convolute
int xStart = halfKernelSize;
int xEnd = width + halfKernelSize;
int yStart = halfKernelSize;
int yEnd = height + halfKernelSize;
for (int x = xStart; x < xEnd; x++)
{
for (int y = yStart; y < yEnd; y++)
{
double localSum = 0.0;
// inside kernel
for (int k = -1 * halfKernelSize; k <= halfKernelSize; k ++)
{
localSum += expandSrc[y, x + k] * kernel[k + halfKernelSize];
}
expandDst[y, x] = localSum;
}
}
// shrink dst matrix
PZMath_matrix dstMatrix = expandDst.BoundMirrorShrink(kernelSize, kernelSize);
return dstMatrix;
}
/// <summary>
/// kernel spatial convolution, mirror expand before convolution
/// </summary>
/// <param name="kernel"></param>
/// <returns></returns>
private PZMath_matrix Convolute2DMirrorExpand(PZMath_matrix kernel)
{
// kernel info
int kernelHeight = kernel.RowCount;
int kernelWidth = kernel.ColumnCount;
int halfKernelHeight = (kernelHeight - 1) / 2;
int halfKernelWidth = (kernelHeight - 1) / 2;
// matrix info
int height = row;
int width = col;
// expand src matrix
PZMath_matrix expandSrc = this.BoundMirrorExpand(kernelHeight, kernelWidth);
PZMath_matrix expandDst = new PZMath_matrix(expandSrc);
// spatial convolute
//int xStart = halfKernelWidth - 1;
//int xEnd = width - halfKernelWidth;
//int yStart = halfKernelHeight - 1;
//int yEnd = height - halfKernelHeight;
int xStart = halfKernelWidth;
int xEnd = width + halfKernelWidth;
int yStart = halfKernelHeight;
int yEnd = height + halfKernelHeight;
for (int x = xStart; x < xEnd; x++)
{
for (int y = yStart; y < yEnd; y++)
{
double localSum = 0.0;
// inside kernel
for (int kx = -1 * halfKernelWidth; kx <= halfKernelWidth; kx++)
{
for (int ky = -1 * halfKernelHeight; ky <= halfKernelHeight; ky++)
{
//localSum += expandSrc[y, x] * kernel[ky + halfKernelHeight, kx + halfKernelWidth];
localSum += expandSrc[y + ky, x + kx] * kernel[ky + halfKernelHeight, kx + halfKernelWidth];
}
}
expandDst[y, x] = localSum;
}
}
// shrink dst matrix
PZMath_matrix dstMatrix = expandDst.BoundMirrorShrink(kernelHeight, kernelWidth);
return dstMatrix;
}