Converting Curriculum Materials to Digital Form

Index

Overview

Here we describe guidelines for digitizing existing curriculum materials in order to make them more flexible so they can be used by learners across a broad spectrum of needs. Please be sure you understand how Copyright and Fair Use applies to the materials you are digitizing.

Text

Digital text, known as ASCII text, is a pliable medium that can be represented in the computer in multiple ways. ASCII can appear as letters on the screen or as spoken words through speech synthesis. Further, the appearance of the text (font, font size, color) can easily be modified and the text can be edited.

Converting printed text to digital form requires a scanner and special software. Three main types of scanners are available: flatbed, single page, or handheld. With a flatbed you can scan text from books by placing the page face down on the glass window. Single page scanners (e.g., PaperPort) require loose sheets that can be fed through the scanner. Hand held scanners are passed over text, sometimes requiring multiple passes depending upon the column width of the text.

When scanning text, the computer creates a picture of the text. That picture must be converted to ASCII text through the use of optical character recognition (OCR) software. This software looks at the pattern of dots in the picture of text and "recognizes" the letters in much the same way we do while reading. When the computer has finished recognizing, the text is converted to ASCII text. OCR software comes with most scanners.

To scan text into the computer, use the scan function that comes with the OCR software package, or, if you have already scanned the page using an image program, open the image file in your OCR program. Higher resolution is better Generally, your scan should be at least 300 dpi (dots per inch). Once you have an image of the text, you should be able to press one button to begin the recognition process. The software begins recognizing the characters. Good OCR software turns images into text with an error rate of about 1.5-2% (if the original page is a very clean copy) but there will usually be some words that need to be corrected manually. After this is done, the text is ready to be used in a word processor, a Web page, or a program that supports learning by reading text aloud (e.g., CAST eReader).

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Images

Printed images can enhance textual information but they are not any more flexible than printed text. Digital images can be represented in multiple ways and are therefore an important element in universally designed curriculum. Digital images can be created by "scanning" (digitizing) printed images or by using a digital camera.

The same scanner types available for digitizing text can be used to digitize images: flatbed, single sheet, and handheld. Flatbed scanners are the most versatile but also the most expensive. They also require the most space. Scanners come with digitizing software or "plug ins" for image editing software (e.g., Adobe Photoshop).

Digital cameras are now widely available and make images of acceptable quality. Most can only store a few images before you must download the pictures into the computer and clear the camera's memory. It is a relatively automatic process to connect the camera to one of the computer's input ports and send the digital images to the computer. These images are comparable to scanned images.

Once an image has been captured on screen it can be edited, sized, and manipulated in countless ways. Other media explaining the image, such as text or sound, can also be attached to the image so as to represent it in multiple ways.

Some considerations when scanning images:

• Resolution. If you expect to print the image, you may want a high-resolution image, but if you will only be using the image on the computer screen, such as in a Web page or multimedia composition, you should scan it at 72 dpi (dots per inch). Using a higher resolution causes the image to be too large for the screen, creates a large file that takes up unnecessary amounts of hard drive storage, and does not add any more clarity to the on-screen image.

• Color depth. Digital images can be set to several types of colors, from simple black-and-white, through gray scale, to some colors, to millions of colors. Once an image is scanned at a particular color setting it cannot be set to a higher one. It is important to note that the highest color settings create large files and cannot be displayed on most computer monitors. Generally, for on-screen use, you should scan images at 256 colors unless you are sure the device on which you will use it permits a higher setting. Make sure the computer knows if an image is black-and-white or grayscale, otherwise the file size could be much larger than necessary.

• Resolution and color depth have a significant impact on the file size of your digital image. Even if you decide to create a high-resolution, high-color image you may need to pay attention to controlling the file size. At these settings, an image only a few inches square can be too large to fit onto a floppy disk. Several of these images may soon fill the space available on your hard disk as well. Large images may take a long time to transmit over a network or to display within programs. Unless you have ways to manage storage of large files (such as a Zip drive), you may need to reduce color, depth or resolution.

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  Sound

  Sound on tape or live is inflexible in its presentation. Digital sound, like digital text and images, can be multiply represented. For example it can be presented with text translations or descriptions, either with the sound or instead of the sound, on screen.

  Live or tape recorded sound can be digitized into the computer and then edited. Most computers that have sound capability provide a simple program to record sounds through a microphone connected to the computer. Instead of the microphone, it is also possible to connect a stereo or tape recorder to the computer via the stereo's headphone jack. Using sound digitizing software, you can capture songs, speech, or other sounds, and save them in files just as you would a word processor document. Sounds can be edited using special software (e.g., SoundEdit). The sound files created can then be used in applications supporting multimedia.

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  Movies

  Digital movies are more flexible than movies on videotape. Digital video editing software enables the addition of text tracks, multiple sound tracks, and visual overlays of graphics or text. Movies can be digitized by connecting a camcorder or VCR to the computer, provided you have appropriate hardware and software. Even short movie files tend to be very large, particularly those with sound and complex images.

  Most digital movie formats compress the file, sacrificing a degree of quality in the process. It is possible to connect a camcorder or VCR to the computer, but it requires some specialized hardware. Software such as Adobe Premiere can be used to create and edit the movie files in the same way that Adobe Photoshop is used to edit image files.

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  Related Links

  Scanners (for Digitizing Text or Images)

  • HP scanners
  • Microtek scanners
  • Epson scanners
  • Buyer's guide to scanners
  • UMAX Technologies scanners
  • Visioneer PaperPort scanners

  OCR Software

  • Caere (OmniPage Pro)
  • CharacterEyes OCR Software
  • Xerox Imaging Systems OCR Software (TextBridge)

  Digital Cameras

  • Panasonic digital cameras
  • Epson digital cameras
  • Kodak digital cameras
  • Olympus digital cameras

  Image Editing

  • Macromedia Freehand
  • Adobe Photoshop
  • Corel PhotoPaint
  • Jasc PaintShop Pro

  Sound Editing

  • Macromedia SoundEdit
  • Avid Software Products

  Movie Editing

  • Macromedia Director (creates Shockwave and QuickTime)
  • Adobe Premiere (creates QuickTime)

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  Page updated January 22, 2001
  
  

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