i3dlib

Documentation

i3d::GradientMagnitudeEstimator

i3d::GradientMagnitudeEstimator< VOXEL > Class Template Reference
[Image preprocessing filters]

This class implements simple Estimator of the gradient magnitude. The Gradient is estimated by simple central differences in the direction of each axe. The Magnitude is computed as the square root of the sum of individual derivatives. More...

#include <LevelSet.h>

Inheritance diagram for i3d::GradientMagnitudeEstimator< VOXEL >:

i3d::ExplicitSchemeFunction< VOXEL > i3d::PDESolverFunction< VOXEL > i3d::SpatialDerivatives< VOXEL > List of all members.

Public Member Functions

virtual VOXEL ComputeUpdate (size_t *neighbors, size_t center)
 Compute the gradient magnitude.
virtual void UpdateTimeStep (size_t *neighbors, size_t index, VOXEL tempTimeStep)
 Udates the Globaltime step from the value returned by ComputeUpdate() method.
virtual void ApplySqrt ()
 Apply the square root on the sum of squares of the derivatives?
virtual void CopyToImage (Image3d< VOXEL > &Img)
 Copy the results to some other image.

Detailed Description

template<class VOXEL>
class i3d::GradientMagnitudeEstimator< VOXEL >

This class implements simple Estimator of the gradient magnitude. The Gradient is estimated by simple central differences in the direction of each axe. The Magnitude is computed as the square root of the sum of individual derivatives.

The gradient magnitude is computed in a following way.

\[ |\nabla u_{i,j,k}| = \sqrt{\left(\frac{\partial u_{i,j,k}}{\partial x}\right)^2 + \left(\frac{\partial u_{i,j,k}}{\partial y}\right)^2 + \left(\frac{\partial u_{i,j,k}}{\partial z}\right)^2} \]

The derivatives are discretised by simple central differences. The pixel on boundary are served in the sense of zero flux neumann boundary conditions. The Magnitude is estimated by calling the ComputeUpdateData() method.

The example of use in the program: 

  .............
  Image3d<float> Img;
  GradientMagnitudeEstimator<float> GME(Img);
  GME->ComputeUpdateData();
  .............
Author:
Jan Hubený xhubeny@fi.muni.cz
Date:
2005

The documentation for this class was generated from the following files:

Generated by doxygen