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Direct 3D lossless image compression based on region growing

ELECTRONICS LETTERS 2000年第3期36卷 207-208页

作者： Wu, D Tan, EC Nanyang Technol Univ Sch Appl Sci Singapore 639798 Singapore

A segmentation-based 3D lossless compression method that exploits the dependencies in all three dimensions of volumetric images is proposed.

关键词： image and video coding segmentation-based 3D lossless compression method data compression image segmentation region growing image coding Codes volumetric images direct 3D lossless image compression image processing and restoration image recognition Computer vision and image processing techniques

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Progressive content access to databases of JPEG-compressed images

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IET image PROCESSING 2007年第2期1卷 207-214页

作者： Jiang, J. Feng, G. Yin, Y. Univ Bradford Dept Elect Imaging & Media Commun Bradford BD7 1DP W Yorkshire England Chongqing Univ Chongqing 700332 Peoples R China

Progressive content access provides a mode that allows a coarse version of an image being viewed at a lower computing cost and then gradually refined by subsequent resolution enhancement if required. This proves extremely useful when millions of compressed images and video sequences need to be browsed manually or processed in pixel domain, saving the cost and removing the necessity of full decompression. Such a progressive content access algorithm suitable for all discrete-cosine-transform-based (DCT-based) JPEG and MPEG-compressed files is proposed here. First a theoretical model in approximation of cosine function used in inverse discrete cosine transform (IDCT) with various orders is developed. Following that a progressive content access algorithm, which comprehends both the successive approximation and the spectral selection, is proposed. Further analysis and experiments are reported to show that our proposed algorithm saves computational cost in comparison with JPEG full decompression. Extensive experiments also support that the proposed algorithm achieves encouraging peak signal-to-noise ratio (PSNR) values for reconstructed images even with lower order approximation.

关键词： discrete cosine transforms discrete-cosine-transform-based compressed files MPEG-compressed images video sequences data compression Computer vision and image processing techniques databases image and video coding inverse discrete cosine transform Integral transforms MPEG-compressed files successive approximation IDCT JPEG-compressed images video coding progressive content access transform coding spectral selection video signal processing visual databases JPEG-compressed files reconstructed images

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Segmentation and tracking of moving objects for content-based video coding

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IEE PROCEEDINGS-VISION image AND SIGNAL PROCESSING 1999年第3期146卷 144-150页

作者： Meier, T Ngan, KN Univ Western Australia Dept Elect & Elect Engn Visual Commun Res Grp Perth WA 6907 Australia

To enable content-based functionalities in video coding, a decomposition of the scene into physical objects is required. Such objects are normally not characterised by homogeneous colour, intensity, or optical flow Therefore, conventional techniques based on these low-level features cannot perform the desired segmentation. The authors address segmentation and tracking of moving objects and present a new video object plane (VOP) segmentation algorithm that extracts semantically meaningful objects. A morphological motion filter detects physical objects by identifying areas that are moving differently from the background. A new filter criterion is introduced that measures the deviation of the estimated local motion from the synthesised global motion. A two-dimensional binary model is derived for the object of interest and tracked throughout the sequence by a Hausdorff object tracker. To accommodate for rotations and changes in shape, the model is updated every frame by a two-stage method that accounts for rigid and non-rigid moving parts of the object. The binary model then guides the actual VOP extraction, whereby a novel boundary post-processor ensures high boundary accuracy. Experimental results demonstrate the performance of the proposed algorithm.

关键词： image sequence moving objects segmentation video coding motion estimation high boundary accuracy rigid moving parts scene decomposition feature extraction image segmentation Hausdorff object tracker Filtering methods in signal processing content-based video coding video signal processing moving objects tracking two-dimensional binary model edge detection filter criterion morphological motion filter local motion estimation boundary post-processor performance image recognition tracking image and video coding nonrigid moving parts filtering theory synthesised global motion image sequences video object plane VOP segmentation algorithm experimental results

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Sparse representation based intraframe and semi-intraframe video coding schemes for low bitrates

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IET image PROCESSING 2021年第5期15卷 1128-1143页

作者： Irannejad, Maziar Mahdavi-Nasab, Homayoun Islamic Azad Univ Digital Proc & Machine Vis Res Ctr Najafabad Branch Najafabad Iran Islamic Azad Univ Dept Elect Engn Najafabad Branch Najafabad Iran

This paper proposes some extensions of the successful sparse coding of still images to intraframe and semi-intraframe video coding. The presented frameworks apply the efficient K-singular value decomposition and recursive least squares dictionary learning methods for sparse representation of videos to study their coding performances. In the proposed semi-intraframe schemes, namely, SISC1 and SISC2, only frame-blocks with more than a threshold deviation from the blocks of the previous frame are transmitted/coded. This reduces the required bitrate and prevents the sparse coding of similar blocks, leading to more efficient video coding methods. The results show that the dictionary learning-based intraframe coding improves the rate-distortion performance of the conventional Motion-JPEG and Motion-JPEG2000 at low bitrates for more than about 3 and 0.5 dB of PSNR on average (for 0.2-1 bpp compression), respectively. The proposed methods outperform the basic dictionary learning-based coding, especially for slower changing videos, generally, with more than 3 dB superiority on average over the tested bitrates. These schemes even present superior performance than the HEVC in the intramode for the complex textured or cluttered scenes. The proposed SISC2 method also saves up to about 50% of the sparse coding computational cost by preventing the coding of more similar frame-blocks.

关键词： Algebra image and video coding Computer vision and image processing techniques video signal processing Algebra

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Keypoint based comprehensive copy-move forgery detection

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IET image PROCESSING 2021年第6期15卷 1298-1309页

作者： Diwan, Anjali Sharma, Rajat Roy, Anil K. Mitra, Suman K. DA IICT Gandhinagar 382007 Gujarat India

Verifying the authenticity of a digital image has been challenging problem. The simplest of the image tampering tricks is the copy-move forgery. In copy-move forgery copied portion of the image is pasted on another part of the same image. Geometrical transformations are used on the copied portions of the image before pasting it for the tampered image to look realistic and visually convincing. To make it more complex, other processing approaches may also be applied in the forged region for hiding traces of forgery. These processings are the scale, rotation, JPEG compression, and AWGN. In this paper, an approach based on features of the CenSurE keypoint detector and FREAK descriptor is proposed. This combination has novelty in itself as it has never been used for this purpose before to the best of authors' literature studies. CenSurE detectors are fast and give stable and accurate output even in the case of rotated images, which we club with binary descriptor FREAK. Hierarchical clustering and Neighbourhood search is applied in such a way that it can locate and detect multiple copy-move forgeries. The authors are hopeful that the proposed approach may be used in real-time image authentication and copy-move forgery detection.

关键词： Optical, image and video signal processing image and video coding image recognition Computer vision and image processing techniques

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Quality-of-service management for broadband residential video services

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ELECTRONICS & COMMUNICATION ENGINEERING JOURNAL 2001年第6期13卷 265-275页

作者： Green, RJ Woolley, SI Garnham, NW Jones, KP Fujitsu Telecommun Europe Ltd Birmingham B37 7YU W Midlands England Univ Birmingham Sch Elect & Elect Engn Birmingham B15 2TT W Midlands England

This paper introduces an approach to managing quality-of-service (QoS) for a residential video-on-demand (VoD) service employing MPEG-2 transport streams using an experimental asynchronous transfer mode (ATM)/asymmetric digital subscriber line (ADSL) access network testbed. The paper examines the complex multilayer propagation of ATM layer parameters over an underlying physical layer and their relationship to video quality. The results obtained from the testbed provide an important insight into the factors relevant to the provisioning and management of new multiservice network infrastructures. Overall, these results contribute to an understanding of the multilayer QoS relationship and provide a basis for comparison with, and development of, similar systems. The paper proposes a method to aid the comparison of results based on a multilayer QoS approach.

关键词： Subscriber loops asymmetric digital subscriber line multilayer QoS broadband networks quality of service packet switching physical layer multilayer propagation video on demand and video servers residential VoD service ATM/ADSL access network testbed quality-of-service management multiservice network infrastructures MPEG-2 transport streams video on demand telecommunication network management video decoding broadband residential video services digital subscriber lines Network management image and video coding asynchronous transfer mode ATM layer parameters video signal processing video quality video coding

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Exploiting texture characteristics and spatial correlations for robustness metric of data hiding with noisy transmission

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IET image PROCESSING 2021年第13期15卷 3160-3171页

作者： Chen, Yanli Wang, Hongxia Wu, Hanzhou Zhou, Yonghui Zhou, Limengnan Chen, Yi Guizhou Normal Univ Sch Big Data & Comp Sci Guiyang Guizhou Peoples R China Sichuan Univ Sch Cyber Sci & Engn Chengdu 610065 Peoples R China Shanghai Univ Sch Commun & Informat Engn Shanghai Peoples R China Univ Elect Sci & Technol China Zhongshan Inst Sch Elect & Informat Engn Zhongshan Guangdong Peoples R China Southwest Jiaotong Univ Sch Informat Sci & Technol Chengdu Sichuan Peoples R China

Data hiding aims to embed a secret message into a digital object such as image by slightly modifying the object content without arousing noticeable artefacts. The resultant object containing hidden information will be sent to a desired receiver via some insecure channels, e.g. images transmitted through noisy channel, social networks are vulnerable to unknown pollution or compression by a third party, which may lead the transmitted objects to be attacked such that the reconstructed message has a significant error rate. It therefore requires us to use robust embedding strategies for data hiding to realise reliable message retrieval. To this end, in this paper, a metric model to estimate the robustness of data hiding for noisy transmission based on the statistical characteristics of cover and embedding operation is presented, the former is mainly reflected by spatial frequency and texture feature, and the latter embedding operation is mainly reflected by embedding modification. The goal is to ensure that both statistical characteristics and embedding operation can be used to maximise the embedding robustness. To the best knowledge, it is the first time to estimate robustness before data hiding by a special metric model. Experimental results show that, by combining the proposed metric model in three classical data hiding methods, i.e. BPS, DE and QIM, the robustness can be significantly improved, which demonstrates its superiority and applicability.

关键词： Cryptography Optical, image and video signal processing image and video coding Computer vision and image processing techniques Data security Other topics in statistics Other topics in statistics

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Combined significance map coding for still image compression

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IET image PROCESSING 2011年第1期5卷 55-62页

作者： Wang, Y-L. Wang, J. -X. Su, A. W. Y. Natl Cheng Kung Univ Dept CSIE Tainan 70101 Taiwan

Set partitioning in hierarchical trees (SPIHT) was known for its relatively simple implementation and flexible scalability when it is combined with discrete wavelet transform (DWT). The authors propose a method called combined significance map coding (CSMC) to improve the coding efficiency of SPIHT when used with block-based discrete cosine transform (DCT). CSMC groups some blocks and encodes the combined significance map of one to several blocks together. Lots of bits spent in significance map coding can be saved when the trees constructed with block DCT coefficients have similar locality. From our simulation results, CSMC improves significantly when in comparison with the original SPIHT coder using DWT and DCT. It also yields better performance than JPEG2000, and even outperforms the non-scalable H. 264 intra-mode coder for some test images. No coding table is required, and fine rate/quality scalability property of SPIHT is still preserved.

关键词： discrete cosine transforms SPIHT coder block-based discrete cosine transform discrete wavelet transform data compression Computer vision and image processing techniques image and video coding still image compression image coding Integral transforms discrete wavelet transforms set partitioning JPEG2000 trees (mathematics) set theory Combinatorial mathematics hierarchical trees nonscalable H.264 intra-mode coder combined significance map coding

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Fast encoding method for vector quantisation of images using subvector characteristics and Hadamard transform

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IET image PROCESSING 2011年第1期5卷 18-24页

作者： Chen, S. X. Li, F. W. Chongqing Univ Posts & Telecommun Commun & Informat Engn Coll Chongqing 400056 Peoples R China

In a framework of vector quantisation (VQ), the encoding speed is a key issue for its practical applications. To speed up the VQ encoding process, a fast encoding method in the Hadamard transform domain is presented. In the proposed method, a five-step test flow based on two characteristic values, the first element and variance of the transformed subvector, is introduced to reject a large number of unlikely codewords. In order to make full use of the energy-compaction property of an orthogonal transform, the partial distance search (PDS) method is used in its Steps 4 and 5. Experimental results show that the proposed algorithm outperforms most of the existing algorithms, especially in case of larger codebook size and high-detail images.

关键词： five-step test flow Codes high-detail images energy compaction property VQ encoding process orthogonal transform subvector variance image and video coding subvector characteristics Computer vision and image processing techniques Hadamard transforms image coding Hadamard transform fast encoding method partial distance search method Integral transforms images quantisation vector quantisation

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General methods for L/M-fold resizing of compressed images using lapped transforms

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IET image PROCESSING 2007年第3期1卷 295-303页

作者： Lee, C. W. Catholic Univ Korea Sch Informat Commun & Elect Engn Bucheon 420743 Kyunggi Do South Korea

Two general methods are proposed for the arbitrary L/M-fold resizing of compressed images using lapped transforms. These methods provide general resizing frameworks in the transform domain. In order to analyse the image size conversion technique using lapped transforrns, the impulse responses and frequency responses for the overall system are derived and analysed. This theoretical analysis shows that the image resizing in the lapped transform domain provides much better characteristics than the conventional image resizing in the discrete cosine transform (DCT) domain. Specifically, by using lapped transforms, the proposed method reduces the blocking effect to a very low level for images which are compressed at low bit rates, since two neighbouring DCT blocks are used in the conversion process, instead of processing each block independently.

关键词： arbitrary L/M-fold resizing discrete cosine transforms lapped transform Computer vision and image processing techniques image size conversion technique image and video coding Data handling techniques frequency response image coding discrete cosine transform domain DCT block image compression Integral transforms data compression impulse response

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