Digital image watermarking using dct with high security of

International Journal of Electronics and Communication Engineering & Technology (IJECET),
INTERNATIONAL JOURNAL OF ELECTRONICS AND
ISSN 0976 – 6464(Print), ISSN 0976 – 6472(Online), Special Issue (November, 2013), © IAEME

COMMUNICATION ENGINEERING & TECHNOLOGY (IJECET)

ISSN 0976 – 6464(Print)
ISSN 0976 – 6472(Online)
Special Issue (November, 2013), pp. 202-209
© IAEME: www.iaeme.com/ijecet.asp
Journal Impact Factor (2013): 5.8896 (Calculated by GISI)
www.jifactor.com

IJECET
©IAEME

Digital Image Watermarking Using DCT with High Security of
Watermark using Image Fusion Technology of
Wavelet Toolbox of MATLAB
Sunil Kr. Sharma1, Divyanshu Varma2
M.Tech Scholar, Department of Electronics & Communication, Bhagwant University, Ajmer, India
1sunilsharma96@gmail.com, 2maildivyanshu@yahoo.com

ABSTRACT: A new area of research to prevent illegal piracy and duplication copying is digital
watermarking. Owing to personal computers being applied in many fields and Internet
becoming popular and easier to use, most information is transmitted with digital format.
Therefore, data copying and back up are more and easier in the World Wide Web and
multimedia. The copyright and authentication gradually lose their security [2]. How to protect
intellectual property becomes important in technical study and research. Recently, the
watermarking technique was proposed to solve the problem of protecting the intellectual
property [5]. The imperceptibility and robustness of watermarking can affect Watermarking
embedded in frequency domain using FFT or DWT or DCT. In this paper, a watermark
embedded in the host image by DCT transform has been proposed [3]. There are several
papers using the same manner to embed watermark into middle-band coefficients of DCT block
but here we proposed a new approach to provide high security as compared to other
developed watermarking tech. using image fusion of wavelet toolbox.

KEYWORDS: Digital image watermarking, discrete cosine transform (DCT), Image fusion,
Synthesized Image, Histograms.

I.

INTRODUCTION

The concept of hiding some data into an image, where data is itself an image is known as Digital
Image Watermarking. Usually watermarking technique embeds the watermarked data in the
main image and all this done by transformation, in which the main image is converted into
frequency domain & then merged with the data and the key usually a PN sequence code, text
code etc. using watermarking embedding system. As shown in following fig. 1 and fig. 2 shows
the reverse process for extraction of watermark using the watermark detection process. In
both figures, we require main image and key, So that we can recover the watermark at the
receiver end. Due to this process the transmission of main image & key with the watermarked
data will increases the complexity, insecurity, piracy etc. To reduce these problems, we
propose that the main image & watermarked image both should be combined and transmitted
International Conference on Communication Systems (ICCS-2013)
B K Birla Institute of Engineering & Technology (BKBIET), Pilani, India

October 18-20, 2013
Page 202


together so that the main image is not required at the receiver end and this increase the
security highly.

Fig. 1: Watermark embedding

Fig. 2: Watermark detection

II.

DCT BASED DIGITAL WATERMARKING

DCT is a general orthogonal transform for digital image processing and signal processing with
advantages such as high compression ratio, small bit error rate, good information integration
ability and good synthetic effect of calculation complexity. One dimensional DCT can be
described with the help of (1) and (2) [1], [4]:
(0) =
( )=

√
√
√

∑
∑

(1)

( )
( ) cos

(

)

(2)

Where F (u) is cosine transform coefficient, u is general frequency variable, u=1, 2, 3…., N-1; if
f(x) is M sequence of time domain, x= 1, 2, 3… N-1, one dimensional inverse discrete cosine
transform is defined as (3) [1], [4]:
( )=

√

( )+√ ∑

( ) cos

√

(

)

(3)

Two dimensional DCT can be defined analogously as (4) [1], [4]:
( , ) = ( ) α(v) ∑

∑

( , ) cos

(

)

cos

(

)

(4)

For u, v =0,1,2,…,N −1 and α(u) and α(v) are defined in (6). The 2D inverse discrete transform is
defined as (5) [1], [4]:

October 18-20, 2013
Page 203

( , )=∑

∑

(

( ) α(v) ( , ) cos

)

cos

(

)

(5)

In both equations (4) and (5) α(u) α(v) is defined as
( ), ( ) =

√

,
,

(6)

√

DCT allows an image to be broken up into different frequency bands namely the high, middle
and low frequency bands thus making it easier to choose the band in which the watermark is to
be inserted. The literature survey reveals that mostly the middle frequency bands are chosen
because embedding the watermark in a middle frequency band does not scatter the watermark
information to most visual important parts of the image i.e. the low frequencies and also it do
not overexpose them to removal through compression and noise attacks where high frequency
components are targeted [3]. Numerous watermarking techniques based on DCT are proposed.
Although some of the watermarking techniques embed the watermark in the DC component,
most techniques utilize the comparison of middle band DCT coefficients to embed a single bit
of watermark information into a DCT block. The middle-band frequencies (FM) of an 8*8 DCT
block can be shown below in fig. 3 [2].

Fig. 3: DCT Regions
DCT block consists of three frequency bands-Low frequency band (FL), High frequency band
(FH), mid frequency band (FM). We have chosen FM for embedding the watermark.
A. Basic Watermarking Process Algorithm (without key)
Common watermarking algorithms usually include two steps: watermark embedding and
watermark detection (extraction) [4]. Let f() denote the embedding function, I the original
watermark, W the watermark to be embedded, then the watermarked image I’ can be
expressed as(7) & shown in fig. 4:
= ( ,

)

(7)

Common approach is as follows: Extract a property sequence from original image V = v1, v2…
vn, corresponding watermark sequence is X = x1, x2… xn. Embed X into V according to certain
model to obtain the adjusted sequence V’ = V + X = v’1, v’2…v’n. Put V’ back and take the place
of V, then we get the watermarked image I’.
Let E( ) denote the detection function and I’ the image to be examined. Extract the watermark
from I’ & extraction shown in fig. 5. The recovered or extracted watermark is given by (8):
= ( , )

(8)
October 18-20, 2013
Page 204


Fig. 4: Watermarking Embedding Process DCT

Fig. 5: Watermark Extraction Process using DCT

October 18-20, 2013
Page 205


III.

PROPOSED TECHNIQUE

From above watermarking at the receiver that main image & watermarked image both are
required. To reduce such requirement only one image can be send by using image fusion of
both images and get the synthesized image using the image fusion technique of wavelet tool
box. Basically image fusion is not only a process to combine two images of same type and size
but also technique to extract required information from images and then combine them to
form a single composite image. The image fusion process can applied in many area of image
processing like remote sensing, military surveillance, medical image analysis etc. complete
process algorithm shown in following fig. 6 [7] and applied process on our image is shown in
fig. 7 using image fusion of MATLAB WAVELET TOOLBOX.

Fig. 6 Image fusion process

Fig. 7 Image fusion using Wavelet toolbox

October 18-20, 2013
Page 206


Fig. 8: Synthesized image
The competitive view of all three images is as shown in fig. 8. This shows the changes in
original image due to watermark and then due to fusion of real and watermarked image which
gives synthesized output image.

Fig. 9: competitive view of all images
Another competitive view can be shown on the basis of their histograms and cumulative
histograms as shown in following figures. The comparison result of all three histograms gives
that the histograms of all images are different with little similarity at different points. All
histograms made at equal bins (50). As shown in following three figures:


October 18-20, 2013
Page 207


Fig. 10: Histograms of main image

Fig. 11: Histograms of Watermarked image

Fig. 12: Histograms of Synthesized image

IV.

CONCLUSION

This paper introduces the image fusion for watermark security with embedding of watermark
with the help of DCT. In this paper we first insert the watermark into main image then this
watermarked image is fused with main image. This synthesized image contains three data main
image, watermark data and watermarked image. Due to this way the requirement of main
image at detection section will reduces with high security. Here we embed the watermark with
the help of DCT but to increase the robustness we may use here DWT also. In the last the
histogram shows a comparative look which makes this technique more different and
impressive and more expressive. The results of simulation shows this system not only security
but also high image quality. The strong capability of embedding signal and anti-attack makes
different this algorithm from all other.

REFERENCES
[1] Mei Jiansheng, Li Sukang1 and Tan Xiaomei, A Digital Watermarking Algorithm Based On
DCT and DWT, Proceedings of the 2009 International Symposium on Web Information Systems
and Applications (WISA’09), Nanchang, P. R. China, May 22-24, 2009, pp. 104-107.

October 18-20, 2013
Page 208


[2] Blossom Kaur, Amandeep Kaur, Jasdeep Singh, Steganographic Approach For Hiding Image
In DCT Domain, International Journal of Advances in Engineering & Technology, July 2011.
[3] Liu Ping Feng, Liang Bin Zheng, Peng Cao, A DWT-DCT Based Blind Watermarking
Algorithm for Copyright Protection, Beijing Institute of Graphic Communication, No. Ed0708.
[4] Abduljabbar Shaamala, Shahidan M. Abdullah and Azizah A. Manaf, Study of the effect DCT
and DWT domains on the imperceptibility and robustness of Genetic watermarking, IJCSI
International Journal of Computer Science Issues, Vol. 8, Issue 5, No 2, September 2011.
[5] Radhika v. Totla, K.S.Bapat, Comparative Analysis of Watermarking in Digital Images Using
DCT& DWT, International Journal of Scientific and Research Publications, Volume 3, Issue 2,
February 2013.
[6] Chin-Shiuh Shieh, Hsiang-Cheh Huang, Feng-Hsing Wang, Jeng-Shyang Pan, Genetic
watermarking based on transform-domain techniques, Pattern Recognition 37 (2004) 555 –
565.
[7] Gengming Zhu, and Nong Sang, Watermarking Algorithm Research and Implementation
Based on DCT Block, International Journal of Electrical and Computer Engineering 4:10 2009.
[8] Franc¸ois Cayre, Caroline Fontaine, and Teddy Furon, Watermarking Security: Theory and
Practice, IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL.XX, NO.Y, XYZ 2005.
[9] Chiou-Ting Hsu and Ja-Ling Wu, Hidden Digital Watermarks in Images, IEEE Transactions
On Image Processing, Vol. 8, No. 1, January 1999.

BIOGRAPHY
Sunil Kumar Sharma was born in Ajmer, Rajasthan, India in 1987. He starts
his technical career from Birla Technical Training Institute, Pilani by
Diploma in Electronics Engineering. He received the Bachelor of Engineering
degree in Electronics & Communication Engineering from M.B.M.
Engineering College, Jodhpur, India in 2011. He has been completed his P.G.
Diploma in Business Administration from SMU-DE, India in 2012. Presently
He is working as Guest Lecturer at Govt. Engineering College Ajmer, Ajmer,
India & pursuing his Master of Technology in Digital Communication from
Bhagwant University, Ajmer, India. His current research interests focus on Signals & Systems,
Signal Processing, Communication systems & Microprocessor.
Divyanshu Varma was born in Ajmer, Rajasthan, India in 1987. He starts
his technical career from Birla Technical Training Institute, Pilani by
Diploma in Electronics Engineering. He received the Bachelor of Technology
degree in Electronics & Communication Engineering from Jaipur National
University, Jaipur, India in 2011. He is pursuing his Master of Technology in
Digital Communication from Bhagwant University, Ajmer, India. His current
research interests focus on Micro-Electronics, Signal Processing and
Communication systems.


October 18-20, 2013
Page 209

Digital image watermarking using dct with high security of

More Related Content

What's hot (20)

Similar to Digital image watermarking using dct with high security of (20)

More from IAEME Publication (20)

Recently uploaded (20)

Digital image watermarking using dct with high security of