dicinterp.hpp

Functions

inline int idx_from_2d(const int x, const int y, const int length)

struct InterpVals

#include <dicinterp.hpp>

namespace for bicubic spline interpolation.

Based on the implementation by GNU Scientific Library (GSL). Main difference is the removal of the binary search for index lookup. For use in DIC, we only ever need integer locations and therefore its sufficient to get the floor value of the subpixel location.

Public Members

double f

double dfdx

double dfdy

class Interpolator

Subclassed by Bspline, Hermite

Public Functions

virtual double eval(const int ss_x, const int ss_y, const double subpx_x, const double subpx_y) const = 0

Evaluates the bicubic interpolation at a specified point.

Computes the interpolated value at (x,y) using bicubic interpolation from the surrounding pixel values.

Parameters:

• x – The x-coordinate of the interpolation point

• y – The y-coordinate of the interpolation point

Returns:

The interpolated value at (x,y)

virtual double eval_dx(const int ss_x, const int ss_y, const double subpx_x, const double subpx_y) const = 0

Evaluates the x-derivative of bicubic interpolation at a specified point.

Computes the partial derivative with respect to x at point (x,y).

Parameters:

• x – The x-coordinate of the point

• y – The y-coordinate of the point

Returns:

The x-derivative of the interpolated function at (x,y)

virtual double eval_dy(const int ss_x, const int ss_y, const double subpx_x, const double subpx_y) const = 0

Evaluates the y-derivative of bicubic interpolation at a specified point.

Computes the partial derivative with respect to y at point (x,y).

Parameters:

• x – The x-coordinate of the point

• y – The y-coordinate of the point

Returns:

The y-derivative of the interpolated function at (x,y)

virtual InterpVals eval_and_derivs(const int ss_x, const int ss_y, const double subpx_x, const double subpx_y) const = 0

Evaluates the bicubic interpolation and its derivatives at a specified point.

Computes the interpolated value and its partial derivatives at (x,y) in a single call.

Parameters:

• x – The x-coordinate of the point

• y – The y-coordinate of the point

Returns:

Data struct containing the interpolated value and its x and y derivatives

virtual ~Interpolator() = default

Public Members

int px_vert

int px_hori