AUDIO WATERMARKING

Eslam Omar Mohamed Faculty of Engineering, Alexandria university

Fourth-year student ,communication and electronics departmenteslamomarmoh@gmail.comTel : 011 11 95 98 39

Information Hiding

Steganography Cryptography Watermarking

After the theater, all clients keep a tab down at Wesley’s Nook.

Attack at dawn

A t t a c K a t d a w N

Steganography

Cryptography

Watermarking

Digital watermarking is a technology which allows a secret message to be hidden in a computer file.

AudioWatermarking

Applications of Watermarking

Rights management

Contents management

Access/copy control

Authentication

WATERMARKING TECHNIQUES

Watermarking

Spatial Domain

Watermarking

Least Significant Bit

SSM-Modulation

Frequency Domain

Watermarking

Discrete Cosine

Transformation

Discrete Wavelet

Transformation

Imperceptibility Robustness Capacity Security not affect the quality of the original signal

resist common signal processing manipulations such as : filteringCompression filteringCropping Resampling

bits that can be embedded in one secondof the host signal

-directly embedded in the signalsnot in a header of the signal.

-only be detected by authorized person

BASIC REQUIREMENTS OF WATERMARKING

Embedding in Dual Channel – More Security

Audio Sample

Right Channel

Left Channel

Synchronization Code Selects the ChannelWatermarked

AudioTrack

5 6 7 8

1 2 3 4

13 14 15 16

9 10 11 12

8 5 6 7

4 1 2 3

16 13 14 15

12 9 10 11

1 2 3 4

13 14 15 16

9 10 11 12

5 6 7 8

Original Watermark

Circular Shifted Watermark- Type 1

Circular Shifted Watermark- Type 2

Circular Shifting of Original Watermark

Spatial domain Least Significant Bit

DC LEVEL SHIFTING

Here watermark is embedded by shifting the DC level of the audio signal.

An input signal is divided into frames of fixed length.

DC level of each frame =Mean of a frame-value in the frame

After that a binary watermark sequence generated randomly is introduced to the shifted signal. This is

achieved by introducing a DC offset level to each frame in the signal according to the watermark bits.

If the watermark bit is 0, the signal is shifted downward.

If the watermark bit is 1, the signal is shifted upward.

DC LEVEL SHIFTING

level0

=-DCBiasMultiplier x FramePower

level1

=+DCBiasMultiplier x FramePower

where

level0

->DC level introduced when a watermark bit is 0

level1

-> the DC level introduced when a watermark bit is 1.

To extract a watermark, a watermarked signal is first divided into frames. Then, the mean of each frame

is calculated. If the mean of a frame is positive, the corresponding watermark bit is 1. Else, the

watermark bit is 0.

The original signal and watermark is not needed in the extraction process. Therefore, DC level shifting is

a blind watermarking scheme

Inverse Discrete Cosine Transform

Audio Data

Block 1

Block 2

Block 3

Block n

Discrete Cosine Transform

DCTData

DCTData

DCTData

DCTData

DCT’Data

DCT’Data

DCT’Data

DCT’Data

Watermark Embedded in Audio

Selecting Mid-Range of DCT Block

…

Mid Range

…

…

DCT- DISCRETE COSINE TRANSFORM

Frequency Domain Watermarking signal to embed

Host signal

Frequency components(using DCT)

Embedding

Extraction

NvvvV ,...,, 10

NxxxX ,...,, 10

NfffF ,...,, 10

iii xff

iii ffx

if = watermared singal

Import audio :

Decode Encode

Embedded info :

Watermark generation for client (unique key)

Upload Audio

Add Client for Audio

Watermarked Audio is sent to client

Unique Watermark stored in database for theft detection

Login Panel

Enter Client Details

PUBLISHER MODULE

Watermark Extraction from audioUpload Audio

Client Information Displayed

Fetching from Database

[ FOUND ]

DETECTION & TRACKING MODULE

Login Panel

KEY BASED

THANK YOU