scholarly journals Large-capacity reversible image watermarking based on improved DE

2021 ◽  
Vol 19 (2) ◽  
pp. 1108-1127
Author(s):  
Shaozhang Xiao ◽  
◽  
Xingyuan Zuo ◽  
Zhengwei Zhang ◽  
Fenfen Li
Keyword(s):  
Image Watermarking ◽  
Visual Quality ◽  
Absolute Difference ◽  
Difference Expansion ◽  
Calculation Algorithm ◽  
Large Capacity ◽  
Difference Operation ◽  
Blind Extraction ◽  
Reversible Image Watermarking ◽  
Embedding Rate

<abstract> <p>Aiming at solving the problems of bad imperceptibility and low embedding rate of existing algorithms, a novel large-capacity reversible image watermarking based on improved difference expansion (DE) is proposed. Firstly, the smoothness calculation algorithm is used to calculate and sort the smoothness values of the divided image sub-blocks; then, the scrambled watermark is embedded into the sub-blocks with less smoothness after removing the abrupt point by using the generalized difference expansion (GDE); finally, the absolute difference operation is applied to the generated overflow pixels to make their pixel values within a reasonable range for embedding watermark information. Under the premise of ensuring a certain visual quality, multiple watermark embedding can effectively improve the embedding rate. The simulation results show that this algorithm not only realizes blind extraction, but also recovers the original images without loss. At the same time, this algorithm achieves a high embedding rate (the average embedding rate is as high as 77.91 dB) without decreasing the visual quality.</p> </abstract>

scholarly journals Reversible Image Watermarking Algorithm Based on Quadratic Difference Expansion

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Zhengwei Zhang ◽  
Mingjian Zhang ◽  
Liuyang Wang
Keyword(s):  
Image Watermarking ◽  
Visual Quality ◽  
Experimental Results ◽  
Original Image ◽  
Difference Expansion ◽  
Image Region ◽  
Embedded Image ◽  
Reversible Image Watermarking ◽  
Embedding Rate

To improve the visual quality and embedding rate of existing reversible image watermarking algorithms, a reversible image watermarking algorithm based on quadratic difference expansion is proposed. First, the pixel points with grayscale values 0 and 255 in the original image are removed, and then, the half-scrambled watermark information is embedded into the original image using linear difference expansion. Finally, the remaining half of the watermark information is embedded into the previously generated watermarked image by the quadratic difference expansion, meanwhile the removed pixel points with grayscale values 0 and 255 in the image are merged, and the final watermarked image is generated accordingly. The experimental results show that the algorithm has both a high embedding rate and a high visual quality, which can completely recover the original image. Compared with other difference expansion watermarking algorithms, it has certain advantages without having to consider the smoothness of the embedded image region.

scholarly journals An improved reversible image watermarking algorithm based on difference expansion

2017 ◽  
Vol 13 (1) ◽  
pp. 155014771668657 ◽  
Author(s):  
Zhengwei Zhang ◽  
Lifa Wu ◽  
Yunyang Yan ◽  
Shaozhang Xiao ◽  
He Sun
Keyword(s):  
Image Watermarking ◽  
Visual Quality ◽  
Information Value ◽  
Original Image ◽  
Difference Expansion ◽  
Image Block ◽  
The Difference ◽  
Carrier Image ◽  
Reversible Image Watermarking ◽  
Embedding Rate

To improve the visual quality and the embedding rate of the existing reversible image watermarking algorithm, an improved reversible image watermarking algorithm based on difference expansion is proposed. First, the watermark information is divided into groups, and the information value of each group is calculated. The watermark group number and the corresponding carrier image block number are mapped, and the corresponding coefficient position of each corresponding carrier block is identified according to the value of the watermark information in each group. Second, the identified location map is compressed and embedded in the original image through the difference expansion. Through circular searching the suitable pixel position, the embedding rate can be effectively improved without sacrificing any visual quality. The experimental results show that the proposed algorithm not only has high embedding rate but also has a high visual quality and can achieve full recovery of the original image. Compared with other algorithms, the algorithm has certain advantages.

Half Difference Expansion Based Reversible Data Hiding Scheme for Medical Image Forensics

2020 ◽  
Vol 16 (4) ◽  
pp. 383-396
Author(s):  
Vazhora Malayil Manikandan ◽  
Nelapati Lava Prasad ◽  
Masilamani Vedhanayagam
Keyword(s):  
Medical Image ◽  
Medical Images ◽  
Visual Quality ◽  
Image Forensics ◽  
Reversible Watermarking ◽  
Difference Expansion ◽  
Data Set ◽  
Watermarking Scheme ◽  
Embedding Rate

Background: Medical image authentication is an important area which attempts to establish ownership authentication and data authentication of medical images. Aims: In this paper, we propose a new reversible watermarking scheme based on a novel half difference expansion technique for medical image forensics. Methods: Conventional difference expansion based reversible watermarking scheme generates watermarked images with less visual quality, and the embedding rate was considerably less due to the high probability of overflow or underflow. In the proposed scheme, the quality of the watermarked image has been improved by modifying the traditional difference expansion based watermarking scheme, half of the difference between two pixels will be expanded during watermarking. The modification of pixels during watermarking is limited by expanding half of the pixel difference, which helps to obtain watermarked images with better visual quality and improved embedding rate due to less chance of overflow or underflow during watermarking. We also propose a tamper detection localization process to detect the tampered regions from the watermarked image. Results: Experimental study of the proposed scheme on the standard medical images from Osrix medical image data set shows that the proposed watermarking scheme outperforms the existing schemes in terms of visual quality of the watermarked image and embedding rate. Conclusion: The overhead related to location map and parity information need to be addressed in future works to improve the proposed scheme.

scholarly journals Wavelet based Reversible Image Watermarking with Logistic Encryption for Health Informatics Systems

2019 ◽  
Vol 8 (2S11) ◽  
pp. 3567-3570
Keyword(s):  
Wavelet Transform ◽  
Execution Time ◽  
Health Informatics ◽  
Binary Data ◽  
Image Watermarking ◽  
Reversible Watermarking ◽  
Integer Wavelet Transform ◽  
Integer Wavelet ◽  
Reversible Image Watermarking ◽  
Watermarking Scheme

Health Informatics systems preserves the patient’s digital records. Two techniques that help in this process are watermarking and encryption. In this paper a reversible image watermarking scheme with logistic encryption is presented. The reversible watermarking is utilizing the concept of integer wavelet transform. The image is divided into sub bands and then the binary data is hidden in these sub bands. The watermarked wavelet sub bands are passed through logistic encryption module which scrambles the coefficients. These coefficients are then sent to inverse wavelet transform for image reconstruction. This process helps encrypt the image though spectral scrambling, thus resulting in faster and better encryption. The proposed algorithm outperforms the exiting algorithms in terms of execution time and the level of encryption.

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