[Numpy-discussion] Update for IM. a small image processing system

RJS rays at san.rr.com
Tue Jan 6 22:52:01 CST 2004


 >  I have uploaded a new version of my small image processing system IM to
 >  "http://members.tripod.com/~edcjones/IM-01.01.04.tar.gz". Most of the code
 >  in IM (pronounced "I'm") is inferior to "nd_image" so I will eventually
 >  convert it all to "nd_image".
...

 > nd_image is however also still being developed and I am looking for 
directions to
 > further work on. I wondered if there is anything you would like to see 
in there?

I have been working with Pythonmagic and numarray for a particular 
astronomy project/technique, and IM has a few things I might use; nd_image 
also has some interesting functions as well.

I want to align and specially stack 8-bit grayscale images from a FITS 
cube, or BMP set, currently. So, my suggestions (hint, hint) are:
1. A method to shift an array to efficiently give the best alignment with 
another. My brute force shifting and subtracting from the main image is 
slow... Most programs I have seen align a selected sub-image, then shift 
the whole image/array (without rotation, although that would be desirable)

My _main_ objective is to stack progressively-longer-exposure 8-bit images 
into 16-bits, with the clipped pixels of longer exposures ignored in the 
summing process. The value of each pixel must be weighted inversely 
proportionately to it's exposure length (so shorter exposures "fill in" the 
clipped areas of the long exposures).

So:
2. A fast method(ology) to do weighted sums of 2D arrays with a mask 
available for each array.

I really do commend Peter and Edward for their contribution!
By the way, if you do wxPython and haven't tried Boa Constructor, you might 
like it. I have been using the CVS version (now .2.8) for a few months, and 
it's working nicely.

Ray Schumacher
http://rjs.org/astro/1004x/





More information about the Numpy-discussion mailing list