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Issue 6.6



Leave Your Mark

Issue: 6.6 (September/October 2008)
Author: JC Cruz
Author Bio: JC is a freelance technical writer living in British Columbia. He writes for various publications, pokes around with Cocoa, Python, and REALbasic, and spends time with his nephew. He can be reached at: anarakisware@gmail.com
Article Description: No description available.
Article Length (in bytes): 50,314
Starting Page Number: 27
Article Number: 6612
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Download Icon 6612.zip Updated: 2013-03-11 19:08:00

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Excerpt of article text...

In today's REALSecure article, we will study the concept of digital watermarks. First, we will learn how a watermark protects an image from unfair use. Then, we will look at three forms of watermark algorithms. Next, we will implement these algorithms into a finite-state machine or FSM. We will then use this FSM to mark a basic test image.

The Problem Of Ownership

One of the challenges faced by today's digital artists is to protect their images against unfair use. When they share their image files with other people, using either physical media or the Net, they expose those files to potential abuse. For instance, an unscrupulous user may add a copy of the image, unmodified and without permission, into their image files (plagiarism). Another may try to pass the image file as their own (theft). Others may even create and sell copies of the image without compensation to the original artist.

There are several ways a digital artist can protect their work. One simple way is to "sign" their work using their name or website's URL. But in order to avoid marring the image, they have to place the signature near the image's corner or side. A casual thief can then use basic image software, like Gimp or Picasa, to remove that signature by cropping. Also, a text signature is easy to forge or replace, making it harder for the artist to prove his ownership.

Another way is to use a digital version of an age-old technique called a watermark.

The Watermark Concept

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