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Wavelet transform modulus maxima-based robust logo watermarking

IET image PROCESSING 2020年第4期14卷 697-708页

作者： Barr, Mohammad Serdean, Cristian Northern Border Univ Dept Elect Engn Ar Ar Saudi Arabia De Montfort Univ Sch Engn & Sustainable Dev Leicester Leics England

Digital image watermarking is used to protect the copyright of digital images. In this study, a novel blind logo image watermarking technique for RGB images is proposed. The proposed technique exploits the error correction capabilities of the human visual system. It embeds two different watermarks in the wavelet/multiwavelet domains. The two watermarks are embedded in different sub-bands, are orthogonal, and serve different purposes. One is a high capacity multi-bit watermark used to embed the logo, and the other is a 1-bit watermark which is used for the detection and reversal of geometrical attacks. The two watermarks are both embedded using a spread spectrum approach, based on a pseudo-random noise sequence and a unique secret key. Robustness against geometric attacks such as rotation, scaling, and translation (RST) is achieved by embedding the 1-bit watermark in the wavelet transform modulus maximacoefficients of the wavelet transform. The experimental results show that the proposed watermarking technique has better distortion parameter detection capabilities and compares favourably against existing techniques in terms of robustness against geometrical attacks such as RST.

关键词： watermarking image watermarking random noise wavelet transforms copyright image coding geometrical attacks geometric attacks 1-bit watermark distortion parameter detection capabilities modulus maxima-based robust logo watermarking digital image watermarking digital images novel blind logo image watermarking technique RGB images error correction capabilities human visual system different watermarks different sub-bands high capacity multibit watermark

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Fiber-optic subcarrier multiplexed CDMA local-area networks for subband image transmission

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 1996年第9期14卷 1866-1878页

作者： Chang, PR Chang, CC Department of Communication Engineering National Chiao Tung University Hsinchu Taiwan

This paper investigates the application of subcarrier multiplexed code-division multiple-access (CDMA) techniques to image transmission over fiber-optic local-area networks (LAN's), In the hybrid scheme, CDMA is used to suppress the interference caused by the laser nonlinearity in the subcarrier multiplexing (SCM) fiber-optic communication systems, Likewise, the SCM scheme is able to increase the channel data rate of CDMA systems, This hybrid system combines the advantages of both schemes and is particularly well suited to subband coding that divides the image information into multiple parallel data streams using an analysis filter bank, each of which is transmitted via a unique subcarrier-code pair, where the spreading code and subcarrier frequency correspond to the image and one of its subbands, respectively, This hybrid scheme also allows more than one image to be transmitted and be accessed simultaneously at the same channel bandwidth, in which each image is assigned a particular spreading code added to its digital data modulating the subcarrier. After transmission, each received signal is independently recovered at a high-Q surface acoustic wave (SAW) receiver with the matching subcarrier-code pair, Other concurrent signals are rejected by the SAW, Then, all the recovered subbands are reassembled by a synthesis filter bank into a close reproduction to the original image, In this paper, the image quality of subband image transmission via CDMA/SCM fiber-optic channels is evaluated and examined.

关键词： Multiaccess communication Local area networks Optical fiber communication Optical fiber LAN Surface acoustic waves image communication Filter bank Interference suppression Fiber lasers image coding

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SHAPE DECOMPOSITION AND REPRESENTATION USING A RECURSIVE MORPHOLOGICAL OPERATION

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PATTERN RECOGNITION 1995年第11期28卷 1783-1792页

作者： WANG, DM HAESECOAT, V RONSIN, J INST NATL SCI APPL AUTOMAT LABEQUIPE IMAGEF-35043 RENNESFRANCE

This paper presents a recursive morphological operation developed in order to perform efficient shape representation. This operation uses a structuring element as a geometrical primitive to evaluate the shape of an object. It results in a set of loci of the translated structuring elements that are included in the object but which do not overlap. The analysis of its computational complexity shows that it is usually less time-consuming than morphological erosion. By using this operation, an object decomposition algorithm is then developed for shape representation. It decomposes an object into a union of simple and nonoverlapping object components. The object is represented by the sizes and loci of its object components. This representation is information preserving shift and scale invariant, and non-redundant. It has been compared with skeletons, morphological decomposition, chain codes and quatrees in terms of compression ability and image processing facility. Experimental results shows that it is very compact, especially if information loss is allowed. Because of the non-overlap between object components, many image processing tasks can be easily performed by directly using this shape representation.

关键词： SHAPE REPRESENTATION OBJECT DESCRIPTION image DECOMPOSITION MATHEMATICAL MORPHOLOGY RECURSIVE ALGORITHM DATA COMPRESSION image coding

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Flexible tree-structured signal expansions using time-varying wavelet packets

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 1997年第2期45卷 333-345页

作者： Xiong, ZX Ramchandran, K Herley, C Orchard, MT UNIV ILLINOIS URBANAIL 61801 HEWLETT PACKARD CORP PALO ALTOCA 94304

In this paper, we address the problem of finding the best time-varying filter bank tree-structured representation for a signal. The tree is allowed to vary at regular intervals, and the spacing of these changes can be arbitrarily short. The question of how to choose tree-structured representations of signals based on filter banks has attracted considerable attention, Wavelets and their adaptive version, known as wavelet packets, represent one approach that has proved very popular, Wavelet packets are subband trees where the tree is chosen to match the characteristics of the signal, Variations where the tree varies over time have been proposed as the double tree and the time-frequency tree algorithms, Time-variation adds a further level of adaptivity, In all of the approaches proposed so far, the tree must be either fixed for the whole duration of the signal or fixed for its dyadic subintervals (i.e., halves, quarters, etc), The solution that we propose, since it allows much more flexible variation, is thus an advance on the wavelet packet algorithm, the double tree algorithm, and the recently proposed time-frequency tree algorithm. Our solution to the problem is based on casting it in a dynamic programming (DP) setting, Focusing on compression applications, we use a Lagrangian cost of distortion +lambda xrate as the objective function and explain our algorithm in detail, pointing out its relation to existing approaches to the problem, We demonstrate the the new algorithm indeed searches a larger library of representations than previously possible and that overcoming the constraint of dyadic time segmentations gives a significant improvement in practice. Compression experiments over various sources verify the superior performance of the new algorithm.

关键词： Wavelet packets Discrete cosine transforms Filter bank image coding Time frequency analysis Cost function Quantization Casting Dynamic programming Lagrangian functions

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AN IMPROVED LEAST-SQUARES LAPLACIAN PYRAMID FOR image COMPRESSION

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SIGNAL PROCESSING 1992年第2期27卷 187-203页

作者： UNSER, M [a]Biomedical Engineering Instrumentation Program Bldg 13 Room 3W13 National Center for Research Resources National Institutes of Health Bethesda MD 20892 USA

This paper describes two ways of improving Burt and Adelson's Laplacian pyramid, a technique developed for image compression. The Laplacian pyramid is a multi-resolution image representation that captures the loss of information occurring through repeated reduction of the spatial resolution. The generation of this data structure involves the use of two complementary functions: EXPAND, which increases the size of an image by a factor of 2, and REDUCE, which performs the reverse operation. The first modification is the adjunction of a pre-filter to the initial EXPAND function in order to guarantee an image extrapolation that is an exact interpolation of the coarser resolution level. The second refinement is a REDUCE operation modified to. minimize information loss. The corresponding least squares Laplacian pyramid (LSLP) is generated by adding a post-filter to the initial REDUCE function. These new functions have an efficient implementation using recursive algorithms. Preliminary experiments indicate improved performance: for a Gaussian-like kernel (a=3/8), the new EXPAND function exhibits a 2 to 2.5 dB attenuation of the first level of the Laplacian pyramid, while the complete scheme (LSLP) leads to a 4.7 to 8.5 dB improvement in the two images used to test the procedure. For comparable compression ratios, the subjective image quality for the LSLP appears to be significantly better. A theoretical relationship between the present approach and the family of quadrature mirror filter image pyramids is also derived.

关键词： LAPLACIAN PYRAMID MULTIRESOLUTION REPRESENTATION image COMPRESSION image coding GAUSSIAN PYRAMID LEAST SQUARES APPROXIMATION RECURSIVE FILTER QUADRATURE MIRROR FILTERS WAVELET TRANSFORM

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VLSI architecture for SAR data compression

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2002年第2期38卷 427-440页

作者： Jeong, H Park, JH Ryu, HY Kwon, JB Oh, Y POSTECH Dept Elect Pohang 790784 South Korea LG Innoteck Corp Yongin 449910 South Korea

As a step towards a real-time signal aperture radar (SAR) correlator, custom very large scale integration (VLSI) architectures are developed. Considering the extremely short word length of the data, we derive three architectures with massive parallelism in bit space. Unlike frequency methods, no degradation is introduced during convolution. Optimized for time and space, they are highly suited to VLSI implementation, and a small architecture with 80 taps operating at 10 MHz has been built using an FPGA.

关键词： VLSI adders application specific integrated circuits computational complexity convolution correlators data compression field programmable gate arrays image coding image processing equipment parallel architectures pipeline processing radar computing radar Convolution image coding adders image processing equipment Pipeline processing radar computing complexity classes radar Field programmable gate arrays Data compression Very large scale integration Parallel architectures frequency method correlators

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Embedded wavelet coder with multistage vector quantization

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INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY 1997年第5期8卷 444-449页

作者： Liang, KC Li, J Kuo, CCJ UNIV SO CALIF DEPT ELECT ENGN SYSTLOS ANGELESCA 90089 SHARP LABS AMER CARNASWA 98607

An embedded image coder based on wavelet transform coding and multistage vector quantization (VQ) is proposed in this research. We have examined several critical issues to make the proposed algorithm practically applicable. They include the complexity of embedded VQ, design of the successive vector quantizer, significance evaluation of a vector symbol, and integration of wavelet transform coding and vector quantization. It is shown in experiments that the new method achieves a superior rate-distortion performance. (C) 1997 John Wiley & Sons, Inc.

关键词： image coding

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End-to-End Transformer for Compressed Video Quality Enhancement

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IEEE TRANSACTIONS ON BROADCASTING 2024年第1期70卷 197-207页

作者： Yu, Li Chang, Wenshuai Wu, Shiyu Gabbouj, Moncef Nanjing Univ Informat Sci & Technol Engn Res Ctr Digital Forens Sch Comp Sci Minist Educ Nanjing 214500 Peoples R China Nanjing Univ Informat Sci & Technol Jiangsu Collaborat Innovat Ctr Atmospher Environm Nanjing 214500 Peoples R China Nanjing Univ Informat Sci & Technol Engn Res Ctr Digital Forens Sch Software Minist Educ Nanjing 214500 Peoples R China Tampere Univ Dept Comp Sci Tampere 33100 Finland

Convolutional neural networks have achieved excellent results in compressed video quality enhancement task in recent years. State-of-the-art methods explore the spatiotemporal information of adjacent frames mainly by deformable convolution. However, offset fields in deformable convolution are difficult to train, and its instability in training often leads to offset overflow, which reduce the efficiency of correlation modeling. In this work, we propose a transformer-based compressed video quality enhancement (TVQE) method, consisting of Swin-AutoEncoder based Spatio-Temporal feature Fusion (SSTF) module and Channel-wise Attention based Quality Enhancement (CAQE) module. The proposed SSTF module learns both local and global features with the help of Swin-AutoEncoder, which improves the ability of correlation modeling. Meanwhile, the window mechanism-based Swin Transformer and the encoderdecoder structure greatly improve the execution efficiency. On the other hand, the proposed CAQE module calculates the channel attention, which aggregates the temporal information between channels in the feature map, and finally achieves the efficient fusion of inter-frame information. Extensive experimental results on the JCT-VT test sequences show that the proposed method achieves better performance in average for both subjective and objective quality. Meanwhile, our proposed method outperforms existing ones in terms of both inference speed and GPU consumption.

关键词： Transformers Correlation Streaming media Task analysis image coding Optical imaging Video recording Compressed video quality enhancement video compression transformer deep learning

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Satellite image compression by concurrent representations of wavelet blocks

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ANNALS OF TELECOMMUNICATIONS 2012年第1-2期67卷 71-80页

作者： Delaunay, Xavier Chabert, Marie Charvillat, Vincent Morin, Geraldine IRIT ENSEEIHT F-31071 Toulouse 7 France NOVELTIS F-31520 Ramonville St Agne France

This paper proposes a complete compression and coding scheme for on-board satellite applications considering the main on-board constraints: low computational power and easy bit rate control. The proposed coding scheme improves the performance of the current Consultative Committee for Space Data Systems (CCSDS) recommendation for a low additional complexity. We consider post-transforms in the wavelet domain, select the best representation for each block of wavelet coefficients, and encode it into an embedded bit stream. After applying a classical wavelet transform of the image, several concurrent representations of blocks of wavelet coefficients are generated. The best representations are then selected according to a rate-distortion criterion. Finally, a specific bit-plane encoder derived from the CCSDS recommendation produces an embedded bit stream ensuring the easy rate control required. In this article, both the post-transforms and the best representation selection have been adapted to the low complexity constraint, and the CCSDS coder has been modified to compress post-transformed representations.

关键词： image coding Satellite applications Transform coding Wavelet transforms Hadamard transforms

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coding OF DETAILS IN VERY-LOW BIT-RATE VIDEO SYSTEMS

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1994年第3期4卷 317-327页

作者： CASAS, JR TORRES, L Department of Signal Theory and Communications ETSETB-Universitat Politecnica de Catalunya Barcelona Spain

In this paper, the importance of including small image features at the initial levels of a progressive second generation video coding scheme is presented. It is shown that a number of meaningful small features called details should be coded, even at very low data bit-rates, in order to match their perceptual significance to the human visual system. We propose a method for extracting, perceptually selecting and coding of visual details in a video sequence using morpholagical techniques. Its application in the framework. of a multiresolution segmentation-based coding algorithm yields better results than pure segmentation techniques at higher compression ratios, if the selection step fits some main subjective requirements. Details are extracted and coded separately from the region structure and included in the reconstructed images in a later stage. The fact of considering the local background of a given detail for its perceptual selection breaks the concept of ''partition'' in the segmentation scheme. As long as details are not considered as adjacent regions but isolated features spread over-the image, ''detail coding'' can be seen as one step towards the so called feature-based video coding techniques.

关键词： image coding image segmentation image sequences mathematical morphology video signals compression ratios feature-based video coding human visual system image features morphological techniques multiresolution segmentation coding algorithm progressive tran Video sequences image coding coding video equipment image segmentation image sequences mathematical morphology Video signals Visual System compression ratio image feature

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