02-05-2014, 11:56 AM
Watermark Logo in Digital Image using DWT
Watermark Logo.pdf (Size: 769.33 KB / Downloads: 21)
Abstract:
This paper gives the idea of the method digital image
watermarking algorithm which is new popular topic for
research. The Discrete wavelet is the tool used for digital
image watermarking. Wavelet transform has been applied
widely in watermarking research as its excellent multi-
resolution analysis property. The watermark logo is
embedded based on the frequency coefficients of the discrete
wavelet transform. The detailed wavelet coefficients of low
frequency band of the host image are altered by the
watermark logo. The algorithm has been tested under the
presence of attacks like Jpeg compression, bit planer
reduction, cropping, warping etc. The watermark logo is
inserted in the host image in frequency domain which gets
spread over the whole part of the host image in time domain.
INTRODUCTION
igital watermarking allows to add a layer of
protection to images by identifying copyright
ownership and delivering a tracking capability that
monitors and reports where images are being used i.e. it is a
method of hiding information into a host image. Digital
watermarking technique can provide copyright protection
for digital data [1], [12], [13], [14].
Digital watermarking is a covert security feature for
identity documents that enables trusted authentication of
host image like the image of PAN card and other IDs.
Watermarking involves the transformation of a digital
artifact into another token of the same type. Watermarking
is done at the object-level. Almost all watermarking
methods, which have been proposed today, can provide
robust and secret watermark and against various attacks
such as filtering, data compression, warping, cropping etc.
The watermark is robust and secret due to the owner keeps
the algorithm private [6].
PROPOSED SYSTEM
The purpose of proposed project is to hide personal
information into a cover image in perceptually invisible
manner. To achieve this, a mathematical tool Wavelet
transform is selected [3], [4], [8]. Following are the steps to
hide a grayscale image (watermark) into cover image.
RESULT DISCUSSION
The performance of our proposed watermarking
scheme is evaluated by using the different host images. The
simulations are performed in the MATLAB7 software
environment [2]. The following table will give the basic
idea about the variation of performance parameters with
different host image.
CONCLUSION
We have designed the system for digital image
watermarking with a given gray scale logo using a secret
key. The system also provides for a MSE, PSNR and
normalized correlation coefficient ® that determine the
robustness of the logo in the digital image. This is
necessary in the case of fragile watermarks as they can be
easily removed by basic image transformations. In such a
case the imperceptibility of the watermark helps protect it
from malicious attacks.
The robust watermark is embedded in the wavelet
coefficients of LL band of the image to strengthen the
watermark and against various attacks such filtering, data
compressing, and other malicious modification etc. The
developed system also detects and extracts an embedded
watermark from a digital image.
The given system provides the good results against the
attacks like Filtering, Jpeg compression, and bit planer
reduction, warping, cropping, and fading. Out of these,
system gives best result against Jpeg compression and
worst against warping.