[vtkusers] vtkImageLaplacian and vtkImageAppendComponents

[Benjamin King]

Hi all,

I experienced a strange behavior of the two classes in the subject when 
I wanted to derive some simple statistics with a 2D-histogram.

When I run the following code:

------
  package require vtk

  vtkImageEllipsoidSource ellipse
     ellipse SetOutputScalarTypeToFloat
     ellipse SetWholeExtent 0 127 0 127 0 127
     ellipse SetCenter 64 64 64
     ellipse SetRadius 60 60 60
     ellipse SetInValue 255 ;# Using this, the values aren't 0
     #ellipse SetInValue 256 ;# Using this, the values aren't equal
     ellipse SetOutValue 0

  vtkImageLaplacian laplace
     laplace SetDimensionality 3
     laplace SetInput [ellipse GetOutput]

  vtkImageAppendComponents app
     app AddInput [ellipse GetOutput]
     app AddInput [ellipse GetOutput]
     app AddInput [laplace GetOutput] ;# comment that and all is fine

  vtkImageAccumulate accu
     accu SetInput [app GetOutput]
     accu Update

  puts "The first two of the following values should be equal and 0"
  puts "[accu GetMin]"
------

I get the outputs "-1275 -1275 0" (using InValue 255) and "-1280 0 0" 
(using InValue 256).

Similar things happen, when I use non-generic data. The minimum value 
for the image that is fed to the laplacian filter is allways wrong.

It doesn't happen when I use vtkImageGradientMagnitude instead of 
vtkImageLaplacian.


cu
   Benjamin

-- 
There are only 10 types of people in this world:
Those who understand binary, and those who don't.