[vtkusers] *vtkImageLogarithmicScale

[Jianhua Ma]

Hi Dear VTKusers,
 
 Filter: vtkImageLogarithmicScale

 The Logarithmic Transfer Function(LTF):
 VTK Define: 
          f(x)= K*Log(1+x)   
 
(From The Visualization Toolkit,
  An Object-Oriented Approach To 3D Graphics, Page438)     

 But actully If K=1, then:  f(x)=Ln(1+x)
 So the LTF function return: 
    the _Natural_ Logarithm of (1+x), (if K=1).

 For example:
      f(22.32549)=1 * Log(1+22.32549)= 3.149547
      f(1+4.964107E+9)=1 * Log(1+4.964107E+9)= 22.32549

I have the experiences and would like to share. 
Hope this helps.  

--Jianhua