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A robust digital watermarking scheme for
video copyright protection
in the wavelet domain
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RADU O. PREDA, DRAGOS N. VIZIREANU
指導老師：鄭淑真
報告人：潘輝銘
Outline
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 Digital watermarking
 The proposed video watermarking scheme
 Experimental results
 Conclusions
Digital watermarking
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 Digital watermarking 視覺上分為：

可視 (visible)

不可視 (invisible)，不可視的數位浮水印技術上分為：

空間域 (spatial domain)
微調影像訊號大小或數值，置入浮水印

壓縮域 (compressed domain)
利用修改數位影片的壓縮域資料，置入浮水印

變換域 (transform domain) 轉換方法：
 離散傅立葉轉換 (Discrete Fourier Transformation)

離散餘弦轉換 (Discrete Cosine Transformation)

離散小波轉換 (Discrete Wavelet Transformation)
The proposed video watermarking scheme
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 The watermark is embedded in the selected wavelet
coefficients of the luminance Y of every frame of the
video.

First：conversion of the RGB color space into the YCbCr color
space

Second：using the 2D Discrete Wavelet Transform
The proposed video watermarking scheme
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 YCbCr影像壓縮技術，Y表亮暗值，Cr、Cb表彩度，利用
這種格式，可將亮度與彩度分開來處理，壓縮上較有效率

轉換公式：
The proposed video watermarking scheme
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 N階小波轉換
The proposed video watermarking scheme
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 Embedded in of the LH1, HL1 and HH1 is very sensitive
to attacks.
 In the LH3, HL3 and HH3, the perceptual quality of the
video will be significantly altered.
The proposed video watermarking scheme
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 藏入 & 解碼流程：
A×B
流程圖
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 The binary image matrix is transformed into a binary row

vector w of size：P  A B
 Hamming error correction code
b: codeword bits length
b : dataword bits length
Size of the resulting watermark
A
1 0 0 1 1 0
B
w

b
w vector: P  P
b
w
1
0
0
1
1
0
P
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 Spread – spectrum technique 將浮水印訊號打散，嵌入於
影像之離散小波係數當中。當影像遭受惡意攻擊時，仍能
正確地擷取出浮水印訊號。
 A secret key K as seed: S  {s j | s j  {0,1}, j  0,1,..., G} is
generated using the Mersenne–Twister algorithm

Mersenne-Twister algorithm 為一種假的亂數，比起rand( ) 有更好的
亂度，能產生的亂數序列週期非常長。

rand( ) 範圍 1~32727  Mersenne-Twister algorithm (2
19937
的週期，亂數很難「重複」
 1) / 2
流程圖
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 The corresponding spread spectrum sequence：
[ s1 , s2 ,..., sG ], if w(i )  0
w(i)  
, i 1,..., P
[ s1 , s 2 ,..., s G ], if w(i)  1
w
1
0
0
1
1
0
w s1 s 2 .... s G
P
w s1 s2 .... sG
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 Videos of resolution M × N, selected wavelet coefficients
of a frame ：
C 3
MN
, L3
2 ( L 1)
2
 C  FC , F is the number of video frames
C  F 
 G
， [ ] is the integer part operator

 P 
the binary sequence S of size G
流程圖
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 以區塊內之量化值來藏入bit(1 or 0)
dw
block
even embed “0”
quantization
value
odd embed “1”


d 
d 
 1, if x  0
d     2q  q  w  sign d     2q  ， sign ( x)  
 2q 
 2q 
 1, if x  0


w
d : original wavelet coefficient
d w : watermarked wavelet coefficient
q : quantization step
流程圖
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 The secret key K provides the information for the size G
of the watermark.
 The binary sequence S is extracted using：

 d wj  
 , j  1,..., G
s j  mod ulo2  ROUND 
 q 




流程圖
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 Using the 64 bit seed from the secret key K the binary
sequence S 0 corresponding to a ‘‘0” is generated.
 Every extracted sequence S(i), i = 1, ... , P0 the
corresponding watermark bit ：

0, if
w(i )  
1, if

 S (i)  S
G
j 1
k
G
j
2
, j  1,..., G
G
S j (i )  S0 j (i ) 
2

i 1

0 j (i ) 

 Watermark bitstream w0 of size P0 is error corrected.
 The watermark
w of size P is obtained.
Experimental results
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 They are in RGB uncompressed avi format, of 1 s
duration, resolution 352 × 288 and frame rate 30
frames/s.
 The watermark is a binary
image of size 64 × 16 pixels
Experimental results
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 PSNR：(Peak Signal to Noise Ratio) 經過影像壓縮後，
參考PSNR值來認定影像品質，PSNR值越大，代表失真
越少。
 BER：(Bit Error Rate) 衡量數據在受攻擊後，其精確性的
指標，BER值越小，表示過程中誤碼率越低。wout 為析取
浮水印，win 為原始水印，P為浮水印總大小。
Experimental results
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 Used nine attacks to test the robustness:






(1) Blurring using blocks of 2 × 2 pixels.
(2) Brightening by adding Y0 = 5 to the luminance of every pixel.
(3) Adding Gaussian noise of mean 0% and variance 0.05%.
(4) Median filtering using a 3 × 3 pixel neighborhood.
(5) Adding“salt and pepper”noise with density d = 0.05%.
(6) Frame averaging, where the current frame.
f (i ) 



f (i  1)  f (i )  f (i  1)
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(7) Frame removal – three random frames were removed.
(8) JPEG compression of every frame with quality factor Q = 70.
(9) MPEG-2 compression at 4 and 2 Mbps.
Experimental results
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Experimental results
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Experimental results
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 PSNR has values 45 ~ 49 dB.
 The watermarked videos appear visually identical to the
original ones.
Experimental results
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Conclusions
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
The proposed algorithm achieves good resilience again a series of different
attacks in the spatial, temporal and compressed domain.
 Further improvements of the algorithms will be made for a better protection
against these types of attacks and also against other attacks, such as
geometric distortions like scaling, translation and rotation.
 Video watermarking using authentication and can also hidden the message.