1#!/usr/bin/env python
2import vtk
3from vtk.util.misc import vtkGetDataRoot
4VTK_DATA_ROOT = vtkGetDataRoot()
5
6# Performs a correlation in frequency domain.
7s1 = vtk.vtkImageCanvasSource2D()
8s1.SetScalarTypeToFloat()
9s1.SetExtent(0,255,0,255,0,0)
10s1.SetDrawColor(0)
11s1.FillBox(0,255,0,255)
12s1.SetDrawColor(2.0)
13s1.FillTriangle(10,100,190,150,40,250)
14s2 = vtk.vtkImageCanvasSource2D()
15s2.SetScalarTypeToFloat()
16s2.SetExtent(0,31,0,31,0,0)
17s2.SetDrawColor(0.0)
18s2.FillBox(0,31,0,31)
19s2.SetDrawColor(2.0)
20s2.FillTriangle(10,1,25,10,1,5)
21fft1 = vtk.vtkImageFFT()
22fft1.SetDimensionality(2)
23fft1.SetInputConnection(s1.GetOutputPort())
24fft1.ReleaseDataFlagOff()
25fft1.Update()
26# Pad kernel out to same size as image.
27pad2 = vtk.vtkImageConstantPad()
28pad2.SetInputConnection(s2.GetOutputPort())
29pad2.SetOutputWholeExtent(0,255,0,255,0,0)
30fft2 = vtk.vtkImageFFT()
31fft2.SetDimensionality(2)
32fft2.SetInputConnection(pad2.GetOutputPort())
33fft2.ReleaseDataFlagOff()
34fft2.Update()
35# conjugate is necessary for correlation (not convolution)
36conj = vtk.vtkImageMathematics()
37conj.SetOperationToConjugate()
38conj.SetInput1Data(fft2.GetOutput())
39conj.Update()
40# Correlation is multiplication in frequency space.
41mult = vtk.vtkImageMathematics()
42mult.SetOperationToComplexMultiply()
43mult.SetInput1Data(fft1.GetOutput())
44mult.SetInput2Data(conj.GetOutput())
45rfft = vtk.vtkImageRFFT()
46rfft.SetDimensionality(2)
47rfft.SetInputConnection(mult.GetOutputPort())
48real = vtk.vtkImageExtractComponents()
49real.SetInputConnection(rfft.GetOutputPort())
50real.SetComponents(0)
51viewer = vtk.vtkImageViewer()
52viewer.SetInputConnection(real.GetOutputPort())
53viewer.SetColorWindow(256)
54viewer.SetColorLevel(127.5)
55# make interface
56#skipping source
57# --- end of script --
58