LabVIEW and Vision (8.2) 2D FFT - Some differences noted

Hello:
I am attaching a small llb showing the 2d FFT results obtained using both the LabVIEW and Vision (8.2) functions.  Some differences in results are seen.  The Vision results seem to have more components (move the scroll bars to get to approximate vision container center) while the LabVIEW results show only one pixel at near the center that is not zero. I wanted to know if someone can explain the differences seen. 
Given that I might trust the Vision results more, I need to display them either in a vision container of the size shown that autoscales X and Y and does not show scrollbars (i.e. behavior like intensity graph), or I need to be able to convert the vision container results so as to be able to display in intensity graph.  I don't know how to get the vision container to do the fomer and since the results for the vision container are in complex format, it is not clear to me how to do the latter conversion. 
Any thoughts are appreciated.
Sincerely,
Don
Attachments:
2D FFT Comparison.llb ‏2184 KB

Hi Gavin:
The end of my post above proposes to do exactly what you state: converting vision container to array using IMAQ image to array.  But how do you do it?  Remember, the vision container is of type complex - you do not have the option to specifiy complex when using that function. Run the attached and see the error one gets.
It is not clear to me from the references you site why we should get different answers between the two functions.  Does this mean when I go to another function library such as from visual basic or c++ I would get 2 more different answers?  There is some subtle difference between the functions that only the R&D dept. can probably tell us.  On something gross like the 2d fft example (C:\Program Files\National Instruments\LabVIEW 8.2\examples\analysis\dspxmpl.llb\2D FFT of a Pulse.vi) included with LabVIEW, the results are substantially the same.
Sincerely,
Don
Attachments:
2D FFT Comparison.llb ‏2192 KB

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