// Moments vector : [m00, m01, m10, m11, m02, m20, m12, m21, m03, m30]
Vector<double> ComputeMomentVectorForPatch(IntVector2 centerPixel, IImage image)
{
Vector<double> moments = new DenseVector(10);
// M00 = total_intensity
// Mpq = sum{x,y}( x^p*y^q*I(x,y) )
for(int dx = -WindowRadius; dx <= WindowRadius; ++dx)
{
for(int dy = -_ybounds[dx + WindowRadius]; dy <= _ybounds[dx + WindowRadius]; ++dy)
{
if(image.HaveValueAt(centerPixel.Y + dy, centerPixel.X + dx))
{
double val = image[centerPixel.Y + dy, centerPixel.X + dx];
moments[m00] += val;
moments[m01] += dy * val;
moments[m10] += dx * val;
moments[m11] += dx * dy * val;
moments[m02] += dy * dy * val;
moments[m20] += dx * dx * val;
moments[m12] += dx * dy * dy * val;
moments[m21] += dx * dx * dy * val;
moments[m03] += dy * dy * dy * val;
moments[m30] += dx * dx * dx * val;
}
}
}
return moments;
}
public MaskedImage TransfromImageBackwards(IImage image, bool preserveSize = false)
{
MaskedImage undistorted;
FindTransformedImageSize(image.RowCount, image.ColumnCount);
Matrix<double>[] matrices = new Matrix<double>[image.ChannelsCount];
if(preserveSize)
{
undistorted = new MaskedImage(image.Clone());
for(int i = 0; i < image.ChannelsCount; ++i)
{
matrices[i] = new DenseMatrix(image.RowCount, image.ColumnCount);
undistorted.SetMatrix(matrices[i], i);
}
}
else
{
IImage img = image.Clone();
for(int i = 0; i < image.ChannelsCount; ++i)
{
matrices[i] = new DenseMatrix(_finalSize.Y, _finalSize.X);
img.SetMatrix(matrices[i], i);
}
undistorted = new MaskedImage(image.Clone());
}
int R = InterpolationRadius;
int R21 = R * 2 + 1;
for(int x = 0; x < matrices[0].ColumnCount; ++x)
{
for(int y = 0; y < matrices[0].RowCount; ++y)
{
// Cast point from new image to old one
Vector2 oldCoords = Transformation.TransformPointBackwards(new Vector2(x: x, y: y));
Vector2 aa = Transformation.TransformPointForwards(oldCoords);
IntVector2 oldPixel = new IntVector2(oldCoords);
// Check if point is in old image range or points to undefined point
if(oldCoords.X < 0 || oldCoords.X > image.ColumnCount ||
oldCoords.Y < 0 || oldCoords.Y > image.RowCount ||
image.HaveValueAt(oldPixel.Y, oldPixel.X) == false)
{
// Point out of range, so set to black
for(int i = 0; i < image.ChannelsCount; ++i)
{
matrices[i].At(y, x, 0.0);
undistorted.SetMaskAt(y, x, false);
}
}
else
{
// Interpolate value from patch in old image
double[,] influence = new double[R21, R21];
double totalInf = 0;
// For each pixel in neighbourhood find its distance and influence of Pu on it
for(int dx = -R; dx <= R; ++dx)
{
for(int dy = -R; dy <= R; ++dy)
{
double distance = _computeDistance(oldCoords, oldPixel.X + dx, oldPixel.Y + dy);
influence[dx + R, dy + R] = 1.0 / distance;
totalInf += influence[dx + R, dy + R];
}
}
double infScale = 1.0 / totalInf; // Scale influence, so that its sum over all pixels in radius is 1
double[] val = new double[image.ChannelsCount];
for(int dx = -R; dx <= R; ++dx)
{
for(int dy = -R; dy <= R; ++dy)
{
double inf = influence[dx + R, dy + R] * infScale;
// Store color for new point considering influence from neighbours
int ix = Math.Max(0, Math.Min(image.ColumnCount - 1, oldPixel.X + dx));
int iy = Math.Max(0, Math.Min(image.RowCount - 1, oldPixel.Y + dy));
for(int i = 0; i < image.ChannelsCount; ++i)
{
val[i] += image[iy, ix, i] * inf;
}
}
}
for(int i = 0; i < image.ChannelsCount; ++i)
{
matrices[i].At(y, x, val[i]);
}
}
}
}
return undistorted;
}