The magazine of the Melbourne PC User Group For the Bookshelf Major Keary majkeary@netspace.com.au

Wavelets

Not to be confused with the .WAV file format, wavelets "are a mathematical tool for hierarchically decomposing functions ... [and] have also recently been applied to many problems in computer graphics ... [including] image editing and compression, automatic level-of-detail control for editing and rendering curves and surfaces, surface reconstruction from contours, and fast methods for solving simulation problems in 3D modelling, global illumination, and animation". Wavelet image files have a .WI extension, occupy far less space than GIF or JPEG and provide much clearer images.

Just as Markov chains-presently so important in data compression systems-came from mathematical research carried out some one hundred years ago, wavelets derive from the 1873 observations of Karl Weierstrass in which he described what we now call fractals. The name, wavelet, dates from 1940 when it was coined by a seismologist. Fascinating stuff- and you will find more about it in Wavelets for Computer Graphics.

Wavelet theory has many applications; this book concentrates on computer graphics, which encompasses many forms apart from pictures. For example, visual representation of time-series data, medical applications (such as a cross section contour through a human organ), images, and surfaces. If you want to see what wavelets can do, visit http://www.summus.com; it is the site of Summus Ltd., a vendor at the leading edge of wavelet image technology. It has some interesting comparisons between JPEG and wavelet images, but down-load the (free) plug-in viewer first.

If you have an academic or professional interest in computer graphics, either in the area of image compression, image editing, or image querying, this book is an essential resource. It is divided into parts.

Part 1, Images, contains chapters on: HAAR: The simplest Wavelet Basis; Image Compression; Image Editing; and Image Querying.

Part 2 deals with curves and covers the theory of multiresolution analysis.

Part 3 is about surfaces; it deals with surface wavelets and surface applications.

Part 4, Image Simulation, is about modelling, global illumination, and variational modelling.

Part 5 contains appendices: an overview of linear algebra, B-spline wavelet matrices, and Matlab code for B-spline wavelets.

Highly technical, lot's of maths, but very well written. Not a dabbler's guide to wavelets but, for those who want to understand how wavelets work and how they can be applied to computer graphics, this is probably the best single text.

PageMaker

Adobe has its own publishing arm, Adobe Press which is associated with Peachpit Press. The Adobe books are excellent examples of print media, from typographic design to the quality of paper used.

Even though InDesign - a new product-has been released, the huge PageMaker (PM) user base will keep that package alive for quite a long time yet. PageMaker's last version is 6.5 Plus, a stable and powerful DTP package that meets all practical publishing requirements.

A useful resource for PM users is Adobe PageMaker 6.5 Plus Productivity Kit, published in Adobe's Classroom in a Book series. It is not a large text and is intended as a tutorial to enable established users to increase their productivity. This is not for raw beginners; familiarity with PM is assumed.

There are twenty-four projects, each involving typical DTP tasks, that use the example templates and images that come on the PM6.5 Plus CD. They include the use of layers and libraries, image masking, and use of colour.

Each project is based on templates that come with the PM6.5 Plus package. The emphasis is on using, modifying, and organising templates, creating master pages, and using PM efficiently. Anyone who uses PM for tasks where design is an important element should find this a very useful resource. It is not about creating large documents (books, for example) where most of the work is straight body text, although there is project covering reports.

Reprinted from the July 2000 issue of PC Update, the magazine of Melbourne PC User Group, Australia

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