[Numpy-discussion] Help req: IDL --> Numeric/numarray
RJ
rays at san.rr.com
Tue Aug 31 07:05:10 EDT 2004
Hi all,
The current IDL REBIN() thread reminded me to post this here...
I'm trying to port Dr. Hongjie Xie's IDL/ENVI Implementation of the FFT
Based Algorithm for Automatic Image Registration (it calculates shift,
scale and rotation for 2d arrays)
http://www.nmt.edu/%7Ehjxie/xie-paper.pdf
ftp://ftp.iamg.org/VOL29/v29-08-10.zip
to Python/numarray/Numeric and running into some subtle problems.
For instance, the IDL ROT() requires some additional steps to emulate, and
the MAX(array, position) as well.
And, I'm not at all familiar with the correspondence of the FFT
libraries... even the simple shift-only routine I translated
http://rjs.org/astro/1004x/Python/register/shift_idl.py
produces different (incorrect) x shift values than the IDL.
My current code
http://rjs.org/astro/1004x/Python/register/
conforms to Xie's flow as much as possible for now, but should and will be
re-factored when functional; his LogPolar function, to convert rectangular
coordinate arrays to polar, is particularly slow.
I was recently informed that IDL has a usable demo version which I will try
this week, but I would love to hear if anyone else has interest in this.
I think that the algorithm would make a nice standalone module, or perhaps
something for nd_image.
Xie's main examples are registration of satellite Earth imagery, but it
should work just as well looking up ;-)
Thank you,
Ray
Secret anti-spam filter-passing text. Include with reply:
qwertyuiop
More information about the NumPy-Discussion
mailing list