You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

395 lines
12 KiB

// David Eberly, Geometric Tools, Redmond WA 98052
// Copyright (c) 1998-2021
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
// https://www.geometrictools.com/License/Boost/LICENSE_1_0.txt
// Version: 4.0.2019.08.13
#pragma once
#include <Mathematics/Logger.h>
#include <array>
// The interpolator is for uniformly spaced (x,y)-values. The input samples
// F must be stored in row-major order to represent f(x,y); that is,
// F[c + xBound*r] corresponds to f(x,y), where c is the index corresponding
// to x and r is the index corresponding to y. Exact interpolation is
// achieved by setting catmullRom to 'true', giving you the Catmull-Rom
// blending matrix. If a smooth interpolation is desired, set catmullRom to
// 'false' to obtain B-spline blending.
namespace gte
{
template <typename Real>
class IntpBicubic2
{
public:
// Construction.
IntpBicubic2(int xBound, int yBound, Real xMin, Real xSpacing,
Real yMin, Real ySpacing, Real const* F, bool catmullRom)
:
mXBound(xBound),
mYBound(yBound),
mQuantity(xBound* yBound),
mXMin(xMin),
mXSpacing(xSpacing),
mYMin(yMin),
mYSpacing(ySpacing),
mF(F)
{
// At least a 3x3 block of data points are needed to construct the
// estimates of the boundary derivatives.
LogAssert(mXBound >= 3 && mYBound >= 3 && mF != nullptr, "Invalid input.");
LogAssert(mXSpacing > (Real)0 && mYSpacing > (Real)0, "Invalid input.");
mXMax = mXMin + mXSpacing * static_cast<Real>(mXBound - 1);
mInvXSpacing = (Real)1 / mXSpacing;
mYMax = mYMin + mYSpacing * static_cast<Real>(mYBound - 1);
mInvYSpacing = (Real)1 / mYSpacing;
if (catmullRom)
{
mBlend[0][0] = (Real)0;
mBlend[0][1] = (Real)-0.5;
mBlend[0][2] = (Real)1;
mBlend[0][3] = (Real)-0.5;
mBlend[1][0] = (Real)1;
mBlend[1][1] = (Real)0;
mBlend[1][2] = (Real)-2.5;
mBlend[1][3] = (Real)1.5;
mBlend[2][0] = (Real)0;
mBlend[2][1] = (Real)0.5;
mBlend[2][2] = (Real)2;
mBlend[2][3] = (Real)-1.5;
mBlend[3][0] = (Real)0;
mBlend[3][1] = (Real)0;
mBlend[3][2] = (Real)-0.5;
mBlend[3][3] = (Real)0.5;
}
else
{
mBlend[0][0] = (Real)1 / (Real)6;
mBlend[0][1] = (Real)-3 / (Real)6;
mBlend[0][2] = (Real)3 / (Real)6;
mBlend[0][3] = (Real)-1 / (Real)6;;
mBlend[1][0] = (Real)4 / (Real)6;
mBlend[1][1] = (Real)0 / (Real)6;
mBlend[1][2] = (Real)-6 / (Real)6;
mBlend[1][3] = (Real)3 / (Real)6;
mBlend[2][0] = (Real)1 / (Real)6;
mBlend[2][1] = (Real)3 / (Real)6;
mBlend[2][2] = (Real)3 / (Real)6;
mBlend[2][3] = (Real)-3 / (Real)6;
mBlend[3][0] = (Real)0 / (Real)6;
mBlend[3][1] = (Real)0 / (Real)6;
mBlend[3][2] = (Real)0 / (Real)6;
mBlend[3][3] = (Real)1 / (Real)6;
}
}
// Member access.
inline int GetXBound() const
{
return mXBound;
}
inline int GetYBound() const
{
return mYBound;
}
inline int GetQuantity() const
{
return mQuantity;
}
inline Real const* GetF() const
{
return mF;
}
inline Real GetXMin() const
{
return mXMin;
}
inline Real GetXMax() const
{
return mXMax;
}
inline Real GetXSpacing() const
{
return mXSpacing;
}
inline Real GetYMin() const
{
return mYMin;
}
inline Real GetYMax() const
{
return mYMax;
}
inline Real GetYSpacing() const
{
return mYSpacing;
}
// Evaluate the function and its derivatives. The functions clamp the
// inputs to xmin <= x <= xmax and ymin <= y <= ymax. The first
// operator is for function evaluation. The second operator is for
// function or derivative evaluations. The xOrder argument is the
// order of the x-derivative and the yOrder argument is the order of
// the y-derivative. Both orders are zero to get the function value
// itself.
Real operator()(Real x, Real y) const
{
// Compute x-index and clamp to image.
Real xIndex = (x - mXMin) * mInvXSpacing;
int ix = static_cast<int>(xIndex);
if (ix < 0)
{
ix = 0;
}
else if (ix >= mXBound)
{
ix = mXBound - 1;
}
// Compute y-index and clamp to image.
Real yIndex = (y - mYMin) * mInvYSpacing;
int iy = static_cast<int>(yIndex);
if (iy < 0)
{
iy = 0;
}
else if (iy >= mYBound)
{
iy = mYBound - 1;
}
std::array<Real, 4> U;
U[0] = (Real)1;
U[1] = xIndex - ix;
U[2] = U[1] * U[1];
U[3] = U[1] * U[2];
std::array<Real, 4> V;
V[0] = (Real)1;
V[1] = yIndex - iy;
V[2] = V[1] * V[1];
V[3] = V[1] * V[2];
// Compute P = M*U and Q = M*V.
std::array<Real, 4> P, Q;
for (int row = 0; row < 4; ++row)
{
P[row] = (Real)0;
Q[row] = (Real)0;
for (int col = 0; col < 4; ++col)
{
P[row] += mBlend[row][col] * U[col];
Q[row] += mBlend[row][col] * V[col];
}
}
// Compute (M*U)^t D (M*V) where D is the 4x4 subimage
// containing (x,y).
--ix;
--iy;
Real result = (Real)0;
for (int row = 0; row < 4; ++row)
{
int yClamp = iy + row;
if (yClamp < 0)
{
yClamp = 0;
}
else if (yClamp > mYBound - 1)
{
yClamp = mYBound - 1;
}
for (int col = 0; col < 4; ++col)
{
int xClamp = ix + col;
if (xClamp < 0)
{
xClamp = 0;
}
else if (xClamp > mXBound - 1)
{
xClamp = mXBound - 1;
}
result += P[col] * Q[row] * mF[xClamp + mXBound * yClamp];
}
}
return result;
}
Real operator()(int xOrder, int yOrder, Real x, Real y) const
{
// Compute x-index and clamp to image.
Real xIndex = (x - mXMin) * mInvXSpacing;
int ix = static_cast<int>(xIndex);
if (ix < 0)
{
ix = 0;
}
else if (ix >= mXBound)
{
ix = mXBound - 1;
}
// Compute y-index and clamp to image.
Real yIndex = (y - mYMin) * mInvYSpacing;
int iy = static_cast<int>(yIndex);
if (iy < 0)
{
iy = 0;
}
else if (iy >= mYBound)
{
iy = mYBound - 1;
}
std::array<Real, 4> U;
Real dx, xMult;
switch (xOrder)
{
case 0:
dx = xIndex - ix;
U[0] = (Real)1;
U[1] = dx;
U[2] = dx * U[1];
U[3] = dx * U[2];
xMult = (Real)1;
break;
case 1:
dx = xIndex - ix;
U[0] = (Real)0;
U[1] = (Real)1;
U[2] = (Real)2 * dx;
U[3] = (Real)3 * dx * dx;
xMult = mInvXSpacing;
break;
case 2:
dx = xIndex - ix;
U[0] = (Real)0;
U[1] = (Real)0;
U[2] = (Real)2;
U[3] = (Real)6 * dx;
xMult = mInvXSpacing * mInvXSpacing;
break;
case 3:
U[0] = (Real)0;
U[1] = (Real)0;
U[2] = (Real)0;
U[3] = (Real)6;
xMult = mInvXSpacing * mInvXSpacing * mInvXSpacing;
break;
default:
return (Real)0;
}
std::array<Real, 4> V;
Real dy, yMult;
switch (yOrder)
{
case 0:
dy = yIndex - iy;
V[0] = (Real)1;
V[1] = dy;
V[2] = dy * V[1];
V[3] = dy * V[2];
yMult = (Real)1;
break;
case 1:
dy = yIndex - iy;
V[0] = (Real)0;
V[1] = (Real)1;
V[2] = (Real)2 * dy;
V[3] = (Real)3 * dy * dy;
yMult = mInvYSpacing;
break;
case 2:
dy = yIndex - iy;
V[0] = (Real)0;
V[1] = (Real)0;
V[2] = (Real)2;
V[3] = (Real)6 * dy;
yMult = mInvYSpacing * mInvYSpacing;
break;
case 3:
V[0] = (Real)0;
V[1] = (Real)0;
V[2] = (Real)0;
V[3] = (Real)6;
yMult = mInvYSpacing * mInvYSpacing * mInvYSpacing;
break;
default:
return (Real)0;
}
// Compute P = M*U and Q = M*V.
std::array<Real, 4> P, Q;
for (int row = 0; row < 4; ++row)
{
P[row] = (Real)0;
Q[row] = (Real)0;
for (int col = 0; col < 4; ++col)
{
P[row] += mBlend[row][col] * U[col];
Q[row] += mBlend[row][col] * V[col];
}
}
// Compute (M*U)^t D (M*V) where D is the 4x4 subimage containing (x,y).
--ix;
--iy;
Real result = (Real)0;
for (int row = 0; row < 4; ++row)
{
int yClamp = iy + row;
if (yClamp < 0)
{
yClamp = 0;
}
else if (yClamp > mYBound - 1)
{
yClamp = mYBound - 1;
}
for (int col = 0; col < 4; ++col)
{
int xClamp = ix + col;
if (xClamp < 0)
{
xClamp = 0;
}
else if (xClamp > mXBound - 1)
{
xClamp = mXBound - 1;
}
result += P[col] * Q[row] * mF[xClamp + mXBound * yClamp];
}
}
result *= xMult * yMult;
return result;
}
private:
int mXBound, mYBound, mQuantity;
Real mXMin, mXMax, mXSpacing, mInvXSpacing;
Real mYMin, mYMax, mYSpacing, mInvYSpacing;
Real const* mF;
std::array<std::array<Real, 4>, 4> mBlend;
};
}