IMDISP - An MS-DOS-based Image Display Program for Scientific Data

Archibald Warnock, Ron C. Baalke and Michael J. Martin

I. Introduction

IMDISP is a general purpose, interactive image display program for MS-DOS computers. It was originally written under contract to the Jet Propulsion Laboratory in support of the production of the Voyager CD-ROM set, and is now maintained and enhanced solely through volunteer efforts. It is distributed free of charge, and is available at many anonymous FTP sites on the Internet. The current release is version 7.9.

IMDISP has been distributed with a variety of CD-ROM products - NASA's Voyagers to the Outer Planets disks, the International Halley Watch CD-ROM Archive, Magellan's Mission to Venus, as well as products from the National Snow And Ice Data Center, the U. S. Geological Survey and the EROS Data Center, among others.

II. Overview of IMDISP Capabilities

IMDISP supports the so-called Super VGA (1024x768 and 800x600 pixels, 256-color) modes for several different video display board manufacturers, in addition to standard EGA (640x350 pixels, 16-color) and VGA (640x480 pixels, 16-color and 320x200 pixels, 256-color) modes. Partial support for the VESA Super VGA standard interface has been recently added. The current release is solely command-driven.

The program automatically detects and can display a variety of image formats - 8, 16 and 32-bit integer FITS format images and spectra, as well as Planetary Data System (PDS) format, VICAR, GIF and raw raster formats. Displayed images can be saved in PDS or GIF formats. Simple tools for analysis of astronomical spectra are available. A browse function allows automated display of sets of images, and IMDISP commands can be run from an external command file. Cursor movement is controlled by either cursor keys or the mouse.

IMDISP also includes a number of image processing functions - subsampling, zooming in and out, histogram calculation and display and histogram equalization. Profile plots can be created along any line between two points on the displayed image and the actual data values in an image line or in spectra can be plotted. Several image filtering functions are available - convolution, mean and median filters, an edge detection filter, as well as functions to brighten, darken and smear the displayed image. Image arithmetic with multiple image buffers is available, utilizing extended (XMS) or expanded (EMS) memory.

Images can be displayed in either gray scale or in pseudo-color, using one of nine built-in color palettes or by loading external palette files. Palettes can be edited interactively and saved. Real-time palette scrolling is available.

III. Obtaining IMDISP

The most current distribution version of IMDISP is available via anonymous FTP at hypatia.gsfc.nasa.gov in the pub/software/imdisp subdirectory. It is also available at ames.arc.nasa.gov in the subdirectory pub/SPACE/SOFTWARE, and through the MS-DOS archive at SIMTEL-20 and its associated mirror sites, in the GRAPHICS subdirectory. Copies may also be obtained on diskette through the National Space Science Data Center's Coordinated Request and User Support Office at Goddard Space Flight Center.

IV. Acknowledgments

IMDISP is maintained and updated (since version 4.4) by the authors of this report. It was originally written by M. J. Martin, F. Evans and D. Nakamura of the Jet Propulsion Laboratory. The plotting code was originally written by E. Esfandari (Interferometrics). Paradise and Trident video drivers were added by G. Gunnells of the USGS.

We would also like to thank our many users, from whom we continue to receive ideas, bug reports and fixes. They exercise the program in ways we never imagined.

The primary programmers for IMDISP appreciate any feedback on the program, including any problems encountered and suggestions for improvement, and can be contacted at the addresses below: