Secure Skin Tone Based Steganograhy Using Wavelet Transform

8/2/2019 Secure Skin Tone Based Steganograhy Using Wavelet Transform

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SECURE SKIN TONE

BASED STEGANOGRAHY USING WAVELET

TRANSFORM

PROJECT BY: PROJECT GUIDE:DIVYA MATHEW DR. VINU THOMASJIBIN JAMESMANOJ MMEGHA S GEORGEMOHAMMED AL-FAWAZ


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INTRODUCTION

Steganography: The art of hiding the existence of data in another transmission medium to achieve secret communication.

Cover image + Secret message=Stego image

CharacteristicsImperceptibilityRobustnessStatistically undetectable

Skin-tone region : Skin tone detection is performed in HSVW avelet transform : 2D DWT


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Embedding block diagram:

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Extraction block diagram:

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IMAGE LOADINGIMAGE LOADING

M*n sized image is loaded

ORIGINAL IMAGE

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SKIN DETECTIONSKIN DETECTION

HSV colour space

RGB to HSV

Thres hold c hosen as [ h1, s1] & [h2, s2]

IMAGE IN HSV COLOURSPACE


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CONTD.CONTD.

Pixel is classified as skin pixel if [h, s] is in therange

H_range = [0, 0.11] and S_range = [0.2, 0.7].

Put skin pixel as 1 & other as 0

INTERMEDIATE IMAGE


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SKIN TONE DETECTIONALGORITHM


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CROPPINGCROPPING

Done on mask image

Cropped area act as key at decoding side

Cropping is done interactively

Provides enhanced security

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DWTDWT2D Haar DWT is employed.

Splits components into sub bands -LL, LH, HL,HH

Can hide data in LH, HL, HH sub bands as they are lesssensitive to human eyes

Best performance in terms of computation time.

Computation speed is high.

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Step 1: At first, scan the pixels from left to right in horizontal

direction. Then, perform the addition and subtraction operationson neighboring pixels

Step 2: Perform the addition and subtraction operations onneighboring pixels and then store the sum on the top and the

difference on the bottom

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2D HAAR DWT


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a)Original image b)Image after applying first order 2DHaar Dwt


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Filter bank structureThe digital filter bank is set of bandpass filters with either a commoninput or a summed outputAn M M --band analysis filter bank band analysis filter bank is shown below

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An L--band synthesis filter bank band synthesis filter bank is shown below


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Boundary handling Two common boundary policies are circular convolution and

padding :

Circular convolution :

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Mirror padding :

Here the signal is mirrored at the boundary. Thestorage space in the wavelet domain is physicallyenlarged by each iteration step


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Suppose C is the original 8 bit cover image of Mc x Nc pixels. It is denotedas :

C={xij, yij, z ij | 1 < i < Mc, 1 < j < Nc, xij,yij, z ij {0,1,2,,255}}

S is the n-bit secret message represented as:

S={Si | 1 < i < n, Si {0,1}}

Embedding message bit in all pixels of a group using LSBsubstitution. The mathematical representation for LSB is:

xi = xi xi mod 2k + mi

The extracted message is represented as

mi =xi mod 2k

EMBEDDING ALGORITHM


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G rouping nine neighboring pixels of image into one :

FF FF FF

The group of pixels in an image is selected in the random order. The random order can be generated by using linear feedback shift register .


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DECODING PROCESS


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MERGINGMERGING

Merge the cropped stego image with originalimage to get the stego image of size MN.

To perform merging we require coefficients of first and last pixels of cropped area in originalimage.

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SKIN TO N E DETECT I O NINPU T:

2 0


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HSV output image:

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M ask image:

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HARDWARE IMPLEMENTATION

The hardware implementation is done using DSP Starter KitDSK TMS 320C6713.Features of TMS 320C6713 at 225 MHz :

Eight 32-Bit Instructions/Cycle32/64-Bit Data Word

225-, 200-MHz ( G DP), and 200-, 167-MHz (PYP) Clock Rates4.4-, 5-, 6-Instruction Cycle Times1800/1350, 1600/1200, and 1336/1000 MIPS /MFLOPSFour ALUs (Floating- and Fixed-Point)Two Multipliers (Floating- and Fixed-Point)Load-Store Architecture With 32 32-Bit G eneral-Purpose RegistersInstruction Packing Reduces Code Size


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COD E COMPOS E R STUDIO

Code Composer Studio is an integrated developmentenvironment for developing applications for TexasInstruments embedded processors.

CCS includes support for OS level application debug aswell as low-level JTAG based development.Implemented one-level 2D DWTInterfaced DSK TMS320C6713.


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CONCLUSIONCONCLUSION

Fascinating scientific area which falls under theumbrella of security systems

No one can extract message without having thevalue of cropped region and pseudo randomcode key.

Provides fine image quality.

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Secure Skin Tone Based Steganograhy Using Wavelet Transform