可逆浮水印方案旨在從已嵌入浮水印的圖像中恢復原始圖像。我們提出了一種可逆數據隱藏方法（RDH），通過區塊匹配策略將加密圖像嵌入到目標圖像中。與以往的Prediction Error （PE）方法或Histogram Shifting（HS）方法不同，本文探討了如何使用隨機區塊配對方案嵌入浮水印。區塊配對策略用一個區塊的像素來替代另一個指定區塊的像素。通過使用隨機預處理和迭代映射（mapping）策略實現，所提出的方案比僅使用傳統的BPP加密方案更好。實驗結果表明，本技術產生的圖像與目標圖像不只具有相似的視覺效果，並可以利用BPP區塊配對資訊完美恢復原始圖像。

A reversible image watermarking scheme recovers the original image after extracting the embedded watermarks. We propose a reversible data hiding method (RDH) that embeds the secret image into the target image through block matching and Block Pixel Permutation (BPP) table’s strategies. Different from previous reversible data hiding methods, such as basic Prediction Error (PE) or Histogram Shifting (HS), this paper shows how to embed watermark image using randomized block pairing scheme. The block pairing scheme reorders pixel in one block to fit the order of another block pixel. Through the usage of randomized pre-processing and iterated mapping strategy, the proposed scheme performs better than only using the conventional BPP encryption scheme. Experimental results show that the watermarked image has a similar visual effect to the target image but can perfect recover to the original image by using the BPP recovery block pairing information.

Content
1.	INTRODUCTION	1
2.	BACKGROUND REVIEW	5
3.	PROPOSED SCHEME	9
3.1 RANDOM IMAGE PREPROCESSING	9
3.1.1 IMAGE RANDOMNESS	11
3.1.2 DATA EMBEDDING	13
3.1.3 IMAGE RECOVERY	15
3.2 BLOCK MAPPING METHOD	17
3.2.1 BLOCK MATCHING	19
3.2.2 SORTING	21
3.2.3 THRESHOLD VALUE	22
3.2.5 RECOVERY	26
4.	EXPERIMENTAL RESULT	27
4.1 NON-RANDOM IMAGE RESULT	27
4.2 RANDOM IMAGE RESULT	31
4.3 MAPPING METHOD RESULT	35
4.4 MAPPING METHOD WITH THRESHOLD RESULT	38
4.5 COMPARISON	40
5.	CONCLUSION	43
6.	REFERENCE	44






Figures

Figure 1 – An example of an image block with its BPP table with t = 3	5
Figure 2 – Embedding process of using BPP tables of t = 3.	7
Figure 3 – Watermarked image acquisition from the original and target image.	8
Figure 4– Watermarked image Iw in Figure 3.	8
Figure 5 – The embedding processing.	10
Figure 6 – (a) original image: Barbara, (b) target image (c) the random image.	10
Figure 7 – Acquisition of the original random image IR.	12
Figure 8 – Acquisition of the target random image TR.	12
Figure 9 – The acquisition of watermarked random image WR.	13
Figure 10 – Acquisition of watermark image W.	14
Figure 11 – Inverse processing of the BPP encryption method,	15
Figure 12 – The proposed image recovery process.	16
Figure 13- Example of mapping images.	18
Figure 14 – Example of Block matching and average value.	19
Figure 15 – An example of block average table.	20
Figure 16 – Example of Block list and numbering	21
Figure 17 – An example of mapping method.	22
Figure 18 – Example of shifting process.	24
Figure 19 – Original block and BPP.	25
Figure 20 – Example of watermark image.	25
Figure 21– Example of recovery step processing and the original image.	26
Figure 22 - Original image and watermark image (Without random image)	28
Figure 23 - Test images (a)Baboon (b)Barbara (c)Lake (d)Lena (e)Ship	29
Figure 24 - Watermark images	29
Figure 25 – Test image: (a) Lena, (b) Baboon, (c) Barbara, (d) Lake, and (e) Ship.	31
Figure 26 – Encrypting images by the BPP encryption method:	32
Figure 27 – Encrypting images by the BPP encryption scheme:	33
Figure 28 – An example of images	35
Figure 29- Using block mapping encrypting images by the BPP encryption scheme	37
Figure 30 - The result of images	39
Figure 31 – different of watermark image	41
Figure 32 - different of watermark image (a) random image	42

 
Table

Table 1. Example of RDH	1
Table 2. Example of RDHEI	2
Table 3 Example of reversible data hiding in encrypted images transformation(RIT)	3
Table 4. PSNR values.	30

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