The IDL Image Analyzer



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Hello and welcome. We are students at the New Mexico Institute of Mining and Technology in Socorro, NM. This page is the end result of a semester long project in Physics 362; Image Processing. This class, which is funded by NASA through the New Mexico Space Grant Consortium, is designed to teach undergraduate students the tools used in the field of image processing and manipulation.

First of all, "we" are:

Scott Bucholtz (linuxman@alumni.nmt.edu)
Maria Martinez (jupiter1@nmt.edu)
Danielle Rundle (drundle@nmt.edu)

This class is taught by Dr. David Westpfahl (dwestpfa@nmt.edu), with assistance from Dr. Dan Klinglesmith (dklingle@nmt.edu).

Why IDL?

IDL (the Interactive Data Language), a commercially developed image processing package from Exelis Inc. (formerly RSI), was chosen for this project for several reasons. Primarily, it was the package that was first put in front of us when Dr. Westpfahl said to Dr. Klinglesmith on the first day of class, "I think the best thing we can do now is to just leave and let them play." On a side note, that is an excellent teaching method give us an 'A' :). Also, IDL's language has a fairly low learning curve. IDL's documentation is the best we've ever seen (go RSI). IDL is ported to every major OS out there (Linux, several commercial UNIX's, Windows, etc.). Most importantly, IDL is becoming the image processing tool of choice in the field of astrophysics. Personally, we have heard of several machines which are directly linked to (and controlling) telescopes around the world which have IDL installed.

Learning IDL

While preparing for the main project, we did several neat things in IDL. We decided to focus our initial attack on creating images and sequencing them into an animation. The result of this was a 50-frame sequence of an exponential function being varied over time. It was kinda' cool. The programs are here, specifically ebolaep.pro (I felt sick that day) and disp.pro. The frames of the movie are here.

The Bug!

Hey, we aren't as dumb as we look. :] We actually found a bug in IDL. It was with their READ_GIF procedure. The patch is located here. No, we didn't write the patch, but we were the first to find that the procedure didn't work properly. Go us! :)

The Project

For the main project, we decided to analyze the surface of Eros since the NEAR Project and the Shoemaker Spacecraft flight was the "hot topic" of discussion around NASA at this time. We captured several images from the NEAR site and used them to get our data. Some of our favorites are here along with a few non-Eros extra's. Our final program, main.pro was written to be portable outside the NEAR project. It is a front-end to the many graphical display/analytical features of IDL. It reads in a filename, verifies that the file both exists and is of a format that IDL can read, then either animates it (if it's a GIF), or loads it for various interactive displaying/analyzing options (such as several types of 3-D graphing procedures). The only problem with the finished product is the widget handling in Windows NT. I think this (return from NT Close Window 'x') may be another bug in IDL. It wouldn't be humanly possible for a couple of college kids to find two bugs in one semester of working with a commercial product such as IDL, though. We'll see (e-mail response from RSI pending). Anyway, the other test programs (and general evolution of our project) can be seen here.

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