Spring 2012

For more details, and talks in past semesters, consult the full schedule of talks.

Tentative talks:

Interested in speaking?

Past topics can (and should) be repeated occasionally. In addition, here are some topics people might like to hear about:

To give a talk, please contact swig@math.arizona.edu.

Image Conversion Tools

by Mark Hays

Table of Contents

Introduction

This document describes some of the image conversion and manipulation utilities present on the Departmental Sun system.

Overview of the Utilities

There are a number of locally available tools to convert between and manipulate a multitude of existing image formats:


XV
An X-based interactive program for manipulating images. Xv is more suited to interactive use than batch applications. Xv enjoys the ability to interactively grab the contents of windows and save them as images.


ImageMagick
A small suite of programs with powerful image manipulation capabilities. The format conversion program is very flexible, but is larger and slower than Net-PBM.


Net-PBM
A large suite of programs that can convert just about any format to just about any other format. It has limited image manipulation facilities, but does faster image conversion than ImageMagick.
I have included links to most of the Net-PBM and ImageMagick manpages at the end of this document.

We also have several pieces of software that can do color map manipulation:



XV
Xv can do many basic color editing operations on images. To get to the color editor, select its entry under the "Windows" menu. Within this window, you can copy, change, and interpolate colors, as well as do global color transformations.


ImageMagick
The ImageMagick programs can perform a number of global color transformations to a sequence of images; in particular, ImageMagick usually does a nice job of color reduction. If you need to perform a bizarre transformation on a bunch of images, try looking at the mogrify manpage. Chances are, it can do what you want.


IDL
IDL can do some really amazing image manipulation in just a few lines of code. IDL is an array-based programming language (kind of like matlab) with a syntax similar to C, FORTRAN, and PASCAL all rolled into one. The XPALETTE widget in IDL can do all the usual color manipulation stuff. In addition, it supports color interpolation within colormaps. To learn more about IDL check out the SWIG IDL documentation.

Xv is most suitable for interactive work on a few images. The other tools are more suited to batch-style processing of a large number of images. For example, you might use xv to get a colormap just right on a single image, and then run mogrify in a shell script to propagate this colormap to the other images that will make up your movie.

Finally, if you need to touch up or annotate an image, xpaint is a fairly nice program. It is similar to MacDraw.

Links:

Manpages:

http://math.arizona.edu/~swig/documentation/ImgCvt/index.php
Last modified: Mon, 29 Aug 2011 12:33:04 -0600
E-mail: swig@math.arizona.edu
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