Abstract

Recent improvements in digital cameras and scanners have caused these tools to become popular in educational environments. As a result, more and more faculty and staff members are engaged in processing digital images to prepare teaching materials and conduct research. However, they often struggle to organize large numbers of digital images. They also look for efficient methods of editing images, so that they can produce different versions of an image for the Web, email, and printing.

This paper will address strategies for processing images both individually and in batches, as well as techniques for organizing images using inexpensive software. Many of the strategies discussed will work in all three major operating environments: Windows, Unix, and Macintosh. Some tools specific to each platform will also be covered.

Introduction

In recent years, four factors have led to the widespread use of digital images: First, those technologies which make it easier to disseminate images, in particular the World Wide Web and email. Secondly, a drop in the cost of hardware, such as scanners and digital cameras which are used to create digital images. Thirdly, inexpensive hard disks for storage and devices for reading and writing CD-ROMs. Lastly, the low cost of outputting images on a computer display as compared to the high cost of full color printing.

Universities have followed this trend toward a greater use of digital images. Faculty use images as building blocks of course content and for disseminating research data. College administrators utilize images to advertise scholastic programs to attract potential students. Further, campus documents that used to only consist of text are now being reborn on the Web filled with images. Even textual information is often conveyed through digital images because HTML currently lacks strong tools for controlling the appearance and layout of text.

This widespread use of images has created a great demand for tools for their processing and management. A variety of applications that can run on Windows, Macintosh, and Unix computers have been written and are continually being refined as users demand more features. Since these software programs are constantly being enhanced and image-related technologies, such as Web browser software and HTML standards, are rapidly evolving, it is difficult to determine which type of image-processing software is the best for the task at hand.

To alleviate this difficulty, we need to understand digital images in general and learn how to evaluate various image-processing software in particular. This paper will focus on identifying basic characteristics of digital images, introducing software that are available in the market for managing and processing images, and provide criteria for evaluating and selecting these programs.

Basic Characteristics of Digital Imaging

Digital images can be categorized as either vector images or bitmapped images. Created by drawing programs, vector images are generally used to represent lines, polygons, and curves and serve in initial steps when using computer assisted design (CAD) software. In contrast, bitmapped images are used not only to display simple lines and shapes as vector images, but are also used for photographic images, realistic paintings, and other complex subjects. Because of their ability to represent these complex subjects, bitmaps are commonly used for depicting photographic and naturalistic images for use both on the World Wide Web and on paper.