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Frequently Asked Questions

Why are there no files in the "Prototype2" directory on the CD?

If you do not see any files in the Prototypes directories on a Linux system, recompile your kernel with support for ISO-8859 support so that you can view the Joliet extended file names.
(Thanks to Bill Pringlemeir)

What is the picture on the cover of the book?

The short answer is found on the back cover of the book:
Cover photograph (c) Royalty Free/CORBIS and processed using the image framework software provided with this book.

The long answer is more interesting. We wanted the cover image to be something that could be processed with tools we describe in the book. It also had to be something that was visually appealing. For example, one of the very first candidates for the cover was to process a picture of the moon. The left-hand side was left intact, while the right-hand side was run through a 3x3 Laplacian filter. You can see the prototype image by clicking here. I found the absolutely-first prototype which demonstrated what we wanted to achieve on the cover. Click here to see it. Although the quality of the picture is terrible, you can see the direction we were headed in.

We went through many iterations trying to find images which everyone liked. By everyone we mean not only ourselves, but our book editor as well as production and marketing folks at Addison-Wesley. Amy found the image of a brain coral at Corbis which everyone liked. The raw image was 2700x1800 pixels, and underwent the following transformations using a short program I wrote.
  1. Resized the image to the desired size. The production department at Addison-Wesley said the image should be 8.5" width and 300 dpi. However, since a few pixels around the border are lost after every step of image processing, the initial size needed to be slightly larger (2560 pixels). It did not make much sense to resize the image from 2700 pixels to 2560 pixels, so a 2560 pixel-wide window was centered on the original image. The full height of the image was used so it could be trimmed when the cover page was created.
  2. A filtered version of the image was created by using a Laplacian filter on the miage. Because the image is so large, the 3x3 Laplacian filter that is part of our image framework, does not work as well as larger filters to highlight the edges of the coral. We used convolve<> to define a 9x9 Laplacian filter.
  3. Our built-in function, erodeCross<>, was run on the Laplacian image to reduce the noise.
  4. The final output image was computed by blending the original, windowed image, with the processed image. If s is the fraction of pixel value that comes from the original image, (1-s) is the fraction that comes from the filtered image. The value of s was varied slowly (logarithmically) from the left side of the image to the right. On the left-side of the image, 100% of the pixels come from the original image. On the right-side of the image, 100% of the pixels come from the filtered image.

Why is a picture of the moon used frequently in the book?

If you look at texts on image processing, you will frequently see the same image used over and over again, making it easy to compare how different algorithms affect the image. If you look at Pratt's Digital Image Processing (I still use his 1978 edition),
Pratt, W.K. Digital Image Processing, Third Edition. Indianapolis, IN: Wiley, 2001. ISBN 0471018880.
you will see a collection of images used throughout his book.

Astronomical images are very interesting, although many lose their appeal when displayed in Black and White. The picture of the moon we used is incredible (see below). Click here to see the moon image used in the book.

Who took the picture of the Moon used in the book?

The moon picture used in the book is NASA Photo ID: AS11-44-6667 and is titled "View of a full moon photographed from Apollo 11 spacecraft". The photograph was taken from Apollo 11 during its return trip to Earth on 7/21/1969. Our source for this image is from one of these two web sites,


Like most NASA imagery, the image is in the public domain. The right to reproduce these images can be found in these locations,

Photographs are not protected by copyright unless noted. If copyrighted, permission should be obtained from the copyright owner prior to use. If not copyrighted, photographs may be reproduced and distributed without further permission from NASA. If a recognizable person appears in the photograph, use for commercial purposes may infringe a right of privacy or publicity and permission should be obtained from the recognizable person.

All of the images presented on NSSDC's Image Catalog are in the public domain. As such, they may be used for any purpose. NSSDC does ask, however, that you acknowledge NSSDC as the supplier of the data. In addition, where the source of the image (by project or as a specific person) is credited in the text, you should also acknowledge that, too.

A careful observer will notice that the picture we are using differs from the original. This image can be found in numerous places, and in different resolutions, on the web. The original image we used was of lower resolution. During the search to find the original image (which took many days), no higher resolution version could be found. It was then we discovered that the image we were using was flipped and rotated from the original. Instead of using the original image, we flipped and rotated it to be in the same orientation as the image we originally used. Why? We liked it better this way!

Copyright © 2003-2012 Philip Romanik, Amy Muntz . All Rights Reserved.