JOURNAL OF COMPUTERS (JCP)
ISSN : 1796-203X
Volume : 4    Issue : 6    Date : June 2009

The Effect of Wavelet Families on Watermarking
Evelyn Brannock, Michael Weeks, and Robert Harrison
Page(s): 554-566
Full Text:
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Abstract
With the advance of technologies such as the Internet, Wi-Fi Internet availability and mobile access,
it is becoming harder than ever to safeguard intellectual property in a digital form. Digital
watermarking is a steganographic technique that is used to protect creative content. Copyrighted
work can be accessed from many different computing platforms; the same image can exist on a
handheld personal digital assistant, as well as a laptop and desktop server computer. For those
who want to pirate, it is simple to copy, modify and redistribute digital media. Because this impacts
business profits adversely, this is a highly researched field in recent years. This paper examines a
technique for digital watermarking which utilizes properties of the Discrete Wavelet Transform
(DWT).
The digital watermarking algorithm is explained. This algorithm uses a database of 40 images that
are of different types. These images, including greyscale, black and white, and color, were chosen
for their diverse characteristics. Eight families of wavelets, both orthogonal and biorthogonal, are
compared for their effectiveness. Three distinct watermarks are tested. Since compressing an
image is a common occurrence, the images are compacted to determine the significance of such
an action. Different types of noise are also added. The PSNR for each image and each wavelet
family is used to measure the efficacy of the algorithm. This objective measure is also used to
determine the influence of the mother wavelet. The paper asks the question:“Is the wavelet family
chosen to implement the algorithm of consequence?”
In summary, the results support the concept that the simpler wavelet transforms, e.g. the Haar
wavelet, consistently outperform the more complex ones when using a non-colored
watermark.

Index Terms
watermark, digital watermarking, image watermarking, wavelet, discrete wavelet transform