An Improved Reversible Watermarking Algorithm in Wavelet Domain for Two-Dimensional CAD Engineering Graphics

2013 ◽  
Vol 655-657 ◽  
pp. 349-354
Author(s):  
Xiaoli Tu ◽  
Xue Mei Jiang ◽  
Xiao Mei Zhang
Keyword(s):  
Reversible Watermarking ◽  
Digital Design ◽  
Two Dimensional ◽  
Wavelet Domain ◽  
Engineering Graphics ◽  
Affine Transform ◽  
Previous Algorithm ◽  
Chaos Sequence ◽  
Index Modulation ◽  
Good Visibility

With the development of digital design and processing and the explosive growth of the demand for two-dimensional CAD engineering graphics, more attention has been paid on the security and the copyright issues of engineering graphics. In this paper, an improved reversible watermarking algorithm in wavelet domain for two-dimensional CAD engineering graphics is proposed. Firstly, the watermark information is preprocessed by compound chaos sequence. And then, block the graphic and extract all vertexes in each blocks of the 2D CAD engineering graphics, Log-polar Mapping (LPM) and wavelet transform are done to them respectively to achieve the invariance of affine transform. Finally, the encrypted watermark is embedded into detailed coefficients by using improved quantization index modulation (IQIM) scheme. Compared with the original previous algorithm, theoretical analysis and experimental results show that the proposed algorithm has not only good visibility and good reversibility, but also stronger robust against the attacks such as transformation, rotation, equal scaling and entity deleting, tampering or adding etc.

An Effective Reversible Watermarking for 2D CAD Engineering Graphics Based on Improved QIM

2011 ◽  
Vol 3 (1) ◽  
pp. 53-69 ◽  
Author(s):  
Fei Peng ◽  
Yu-Zhou Lei
Keyword(s):  
Reversible Watermarking ◽  
Experimental Results ◽  
Data Recovery ◽  
Quantization Index Modulation ◽  
Secret Key ◽  
Good Balance ◽  
Engineering Graphics ◽  
Watermarking Scheme ◽  
Index Modulation

Quantization index modulation (QIM) is widely used in watermarking, but QIM cannot be applied to reversible watermarking directly due to its inherent limitations. In this paper, an improvement is made to QIM to make it suitable for reversible watermarking. Based on the improved QIM (IQIM), a reversible watermarking scheme for 2D CAD engineering graphics is proposed. The relative amplitudes and the relative phases of entity vertices are used as hosts to carry the watermark, respectively, and the data recovery is controlled by a secret key. Experimental results indicate that the proposed scheme can strike a good balance between capacity, imperceptibility, robustness, security and complexity.

scholarly journals Spatial downscaling of radar-derived rainfall field by two-dimensional wavelet transform

2020 ◽  
Vol 51 (3) ◽  
pp. 456-469
Author(s):  
Vahid Nourani ◽  
Armin Farshbaf ◽  
S. Adarsh
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet ◽  
Main Concern ◽  
Two Dimensional ◽  
Wavelet Domain ◽  
Global Circulation ◽  
Global Circulation Models ◽  
Pattern Display ◽  
Actual Size ◽  
Good Agreement

Abstract Downscaling of rainfall fields, either as images or products of global circulation models, have been the motive of many hydrologists and hydro-meteorologists. The main concern in downscaling is to transform high-resolution properties of the rainfall field to lower resolution without introducing erroneous information. In this paper, rainfall fields obtained from Next Generation Weather Surveillance Radar (NEXRAD) Level III were examined in the wavelet domain which revealed sparsity for wavelet coefficients. The proposed methodology in this work employs a concept named Standardized Rainfall Fluctuation (SRF) to overcome the sparsity of rainfall fields in wavelet domain which also exhibited scaling behaviors in a range of scales. SRFs utilizes such scaling behaviors where upscaled versions of the rainfall fields are downscaled to their actual size, using a two-dimensional discrete wavelet transform, to examine the reproduction of the rainfall fields. Furthermore, model modifications were employed to enhance the accuracy. These modifications include removing the negative values while conserving the mean and applying a non-overlapping kernel to restore high-gradient clusters of rainfall fields. The calculated correlation coefficient, statistical moments, determination coefficient and spatial pattern display a good agreement between the outputs of the downscaling method and the observed rainfall fields.

Watermarking Algorithm Based on Quantization Index Modulation and Singular Value Decomposition

2011 ◽  
Vol 271-273 ◽  
pp. 536-540
Author(s):  
Ying Tian ◽  
Xue Song Peng ◽  
Yun Fei Wei
Keyword(s):  
Singular Value Decomposition ◽  
Coefficient Matrix ◽  
Singular Value ◽  
Quantization Index Modulation ◽  
Wavelet Domain ◽  
Quantization Step ◽  
Geometric Attacks ◽  
Host Image ◽  
Value Decomposition ◽  
Index Modulation

This paper presents a blind watermarking algorithm based on quantization index modulation (QIM) and singular value decomposition (SVD) in the wavelet domain. Obtain approximation sub band of the wavelet domain coefficient matrix by performing a wavelet transform on host image. The QIM technique determines the quantization step for each embedding block. The SVD technique is modified the SVs of each embedding block. The watermark encrypted by a chaos sequence generated by Lorenz chaotic system is embedded the host image. The experiments show that this paper presented algorithm in various attacks against the image has good robustness especially for against geometric attacks and image compression.

A New Robust Reversible Blind Watermarking in Wavelet-Domain for Color Images

2016 ◽  
Vol 16 (02) ◽  
pp. 1650006 ◽  
Author(s):  
P. Manimehalai ◽  
P. Arockia Jansi Rani
Keyword(s):  
Clustering Algorithm ◽  
Color Image ◽  
Reversible Watermarking ◽  
Color Images ◽  
Blind Watermarking ◽  
Wavelet Domain ◽  
Wavelet Coefficients ◽  
Recovered Image ◽  
Host Image

Reversible watermarking methods are used for copyright protection and are able to recover the host image without distortion. Robust reversible watermarking technique should resist against intentional and unintentional image processing attacks. Robust reversible watermarking techniques should have three features namely imperceptibility, reversibility and robustness. In this paper, it is proposed to develop a new robust reversible blind watermarking for color images based on histogram construction of the wavelet coefficients constructed from the cover image. In the proposed approach, the red component of a host color image is decomposed into wavelet coefficients. Motivated by the excellent spatio-frequency localization properties of wavelets, this technique is proposed in the wavelet domain. The pixels are adjusted before watermark embedding such that both overflow and underflow of pixels during embedding is avoided and image is recovered without distortion. Based on histogram construction and the local sensitivity of Human Visual System (HVS) in wavelet domain, the watermark is embedded. For watermark extraction without host image, k-means clustering algorithm is proposed. The experimental results show that the proposed technique has good performance in terms of reversibility and robustness with the high quality of the watermarked image. The PSNR value of the recovered image is around 48[Formula: see text]dB which proves that the quality of the recovered image is not degraded.

scholarly journals Two-Dimensional Index Modulation for the Large-Scale Multi-User MIMO Uplink

2019 ◽  
Vol 68 (8) ◽  
pp. 7904-7918 ◽  
Author(s):  
Siyao Lu ◽  
Mohammed El-Hajjar ◽  
Lajos Hanzo
Keyword(s):  
Large Scale ◽  
Two Dimensional ◽  
Index Modulation
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