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Section 4: Image Manipulation Tools

Introduction

The Multimedia Resources Unit of the Educational Technology Service, University of Bristol, facilitates the electronic capture and manipulation of images and video and encourages the correct use of such resources in computer-based learning materials. In doing so, the unit has realised the necessity to develop a number of software tools for image capture and manipulation.

Two of these tools, i) image processor and ii) palette manipulator, have undergone initial testing in a number of departments at the University of Bristol, the Centre for Personal Information Management, University of the West of England and the Department of Computer Science, University of Glasgow. We now require further feedback on their use and are making an evaluation copy of the two programs available as a beta test release.

I) Image Processor

The image processor was initially developed to assist in the batch processing of images that are currently being digitised from our videodisc based image archive. After digitisation these images are being converted to a resolution of 320 by 240 pixels by 256 colours and saved as GIF files ready for distribution via the World Wide Web. The image processor was developed to carry out a potentially tedious process automatically and unattended.

Remember to carry out any other manipulation needed to the images before reducing size or number of colours.

The program will convert images from one file format, size and colour resolution (colour depth) to another automatically. It is capable of converting all the images in one directory, unlike more conventional image processing software. Other features include the ability to strip unwanted black borders/frames from images (these may occur during over scanning), a review option, and colour balancing.

2) Palette Manipulator

As discussed in section 2, if you want to place more than one 256 colour image at the same time on a screen that is only capable of displaying 256 colours due to the limit of the graphic display card, these images need to have a common palette. The main function of palette manipulator is to optimise palettes from more than one (up to eight) 256 or less colour/greyscale images and produce a common palette.

Availability

Copies are only available electronically via the World Wide Web:
http://www.ets.bris.ac.uk/
This is a fully featured release but it will only function until the time stated on the World Wide Web.

The minimum machine specification required is: 

A personal computer with an 80386 or higher processor
Microsoft Windows 3.1 or later
A hard disc with approximately 1Mb free of disc space for the programs and extra space for any image files
At least 6Mb random-access memory (RAM) - preferably 8Mb
A graphics adapter card capable of displaying at least 256 colours
Optional: a Photo-CD compatible CD-ROM drive for reading Photo-CD images
The Multimedia Resources Unit acknowledges the Joint Information Systems Committee for providing funding for the initial development of these tools as part of a grant under the New Technologies Initiative.

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