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A fast 2-D Otsu lung tissue image segmentation algorithm based on improved PSO

MICROPROCESSORS AND MICROSYSTEMS 2021年 80卷 103527-103527页

作者： Zhao, Yanqiao Yu, Xiaoyang Wu, Haibin Zhou, Yong Sun, Xiaoming Yu, Shuang Yu, Shuchun Liu, He Harbin Univ Sci & Technol Higher Educ Key Lab Measuring & Control Technol & Harbin Peoples R China Harbin Univ Sci & Technol Sch Measurement & Commun Nanjing Peoples R China Harbin Med Univ Hosp 1 Harbin Peoples R China

In order to reduce the time of lung tissue image segmentation, we proposed a fast 2-D Otsu lung tissue image segmentation algorithm based on improved PSO. Firstly, in the 2-D Otsu algorithm, the search scope of 2-D gray threshold is limited in a long and narrow region, which is the neighbourhood of the diagonal from the third region to the first region of the 2-D gray histogram, and the search scope and the computation are reduced, operation speed is improved. Secondly, In the PSO algorithm, the position of the particles is adjusted during iterating based on the principle of symmetric disposition, so as to avoid PSO falling into local optimal solution and improves the accuracy of threshold searching. Finally, a lung CT image with 1280x960 resolutions is segmented by our algorithm and other traditional algorithms, and a comparison is given. The segmentation threshold of our method is 85, the difference is less than 5 comparing with that of other traditional algorithms, and it shows that our method has almost the same searching precision as the traditional algorithms. The time cost is only 162ms, which is far less than the traditional algorithms, and it shows that our method improve the segmentation speed. It can be concluded that our method can not only satisfy the requirement of segmentation precision, but also meet the requirement of operation speed.

关键词： Threshold segmentation Lung CT image Two-dimensional Otsu Improved PSO fast algorithm

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A fast multi grid algorithm for 2D diffeomorphic image registration model?

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JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS 2021年 394卷 113576-113576页

作者： Han, Huan Wang, Andong Wuhan Univ Technol Dept Math Wuhan 430070 Peoples R China Chinese Acad Sci Wuhan Inst Phys & Math State Key Lab Magnet Resonance & Atom & Mol Phys Wuhan 430071 Peoples R China Beijing Univ Aeronaut & Astronaut Minist Educ Sch Math & Systemat Sci Beijing 100191 Peoples R China Beijing Univ Aeronaut & Astronaut Minist Educ Key Lab Math Informat & Behav Semant Beijing 100191 Peoples R China

In Han and Wang (2020), a 2D diffeomorphic image registration model is proposed to eliminate mesh folding. To solve the 2D diffeomorphic model, a diffeomorphic fractional order image registration algorithm (DFIRA for short) is proposed in Han and Wang (2020). DFIRA achieves a satisfactory image registration result but it costs too much CPU time. To accelerate DFIRA, we propose a fast multi grid algorithm for 2D diffeomorphic image registration model in this paper. This algorithm achieves a satisfactory image registration result by using only one-tenth CPU time of DFIRA. At the same time, no mesh folding occurs in proposed algorithm. Furthermore, convergence analysis of the proposed algorithm is also presented. Moreover, numerical tests are also performed to show that the proposed algorithm is competitive compared with some other algorithms. (C) 2021 Elsevier B.V. All rights reserved.

关键词： Diffeomorphic image registration Multi grid No mesh folding fast algorithm

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A Computationally Efficient Neural Video Compression Accelerator Based on a Sparse CNN-Transformer Hybrid Network

A Computationally Efficient Neural Video Compression Acceler...

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27th Design, Automation and Test in Europe Conference and Exhibition (DATE)

作者： Zhang, Siyu Mao, Wendong Shi, Huihong Wang, Zhongfeng Nanjing Univ Sch Elect Sci & Engn Nanjing Peoples R China Sun Yat Sen Univ Sch Integrated Circuits Guangzhou Peoples R China

ISBN: (纸本)9798350348606;9783981926385

Video compression is widely used in digital television, surveillance systems, and virtual reality. Real-time video decoding is crucial in practical scenarios. Recently, neural video compression (NVC) combines traditional coding with deep learning, achieving impressive compression efficiency. Nevertheless, the NVC models involve high computational costs and complex memory access patterns, challenging real-time hardware implementations. To relieve this burden, we propose an algorithm and hardware co-design framework named NVCA for video decoding on resource-limited devices. Firstly, a CNN-Transformer hybrid network is developed to improve compression performance by capturing multi-scale non-local features. In addition, we propose a fast algorithm-based sparse strategy that leverages the dual advantages of pruning and fast algorithms, sufficiently reducing computational complexity while maintaining video compression efficiency. Secondly, a reconfigurable sparse computing core is designed to flexibly support sparse convolutions and deconvolutions based on the fast algorithm-based sparse strategy. Furthermore, a novel heterogeneous layer chaining dataflow is incorporated to reduce off-chip memory traffic stemming from extensive inter-frame motion and residual information. Thirdly, the overall architecture of NVCA is designed and synthesized in TSMC 28nm CMOS technology. Extensive experiments demonstrate that our design provides superior coding quality and up to 22.7x decoding speed improvements over other video compression designs. Meanwhile, our design achieves up to 2.2x improvements in energy efficiency compared to prior accelerators.

关键词： Neural video compression CNN-Transformer fast algorithm pruning hardware accelerator

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On the Computational Complexity of Compressed Power Series

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MATHEMATICAL NOTES 2023年第1-2期114卷 92-98页

作者： Karatsuba, E. A. Russian Acad Sci Fed Res Ctr Comp Sci & Control Moscow 119333 Russia

We present computational algorithms and complexity estimates for power series in which all exponents are positive integers raised to one and the same integer power >= 2.

关键词： algorithm power series computational complexity fast algorithm FEE method Faulhaber's formula Bernoulli numbers

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fast, high-order numerical evaluation of volume potentials via polynomial density interpolation

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JOURNAL OF COMPUTATIONAL PHYSICS 2024年 511卷

作者： Anderson, Thomas G. Bonnet, Marc Faria, Luiz M. Perez-Arancibia, Carlos Rice Univ Dept Computat Appl Math & Operat Res Houston TX USA ENSTA Paris INRIA ENSTA POEMSCNRS F-91120 Palaiseau France Univ Twente Dept Appl Math Enschede Netherlands

This article presents a high -order accurate numerical method for the evaluation of singular volume integral operators, with attention focused on operators associated with the Poisson and Helmholtz equations in two dimensions. Following the ideas of the density interpolation method for boundary integral operators, the proposed methodology leverages Green's third identity and a local polynomial interpolant of the density function to recast the volume potential as a sum of single- and double -layer potentials and a volume integral with a regularized (bounded or smoother) integrand. The layer potentials can be accurately and efficiently evaluated everywhere in the plane by means of existing methods (e.g. the density interpolation method), while the regularized volume integral can be accurately evaluated by applying elementary quadrature rules. Compared to straightforwardly computing corrections for every singular and nearly -singular volume target, the method significantly reduces the amount of required specialized quadrature by pushing all singular and near -singular corrections to near -singular layer -potential evaluations at target points in a small neighborhood of the domain boundary. Error estimates for the regularization and quadrature approximations are provided. The method is compatible with well -established fast algorithms, being both efficient not only in the online phase but also to set-up. Numerical examples demonstrate the high -order accuracy and efficiency of the proposed methodology;applications to inhomogeneous scattering are presented.

关键词： Volume potential Integral equations High-order quadrature fast algorithm

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fast High-Order Compact Finite Difference Methods Based on the Averaged L1 Formula for a Time-Fractional Mobile-Immobile Diffusion Problem

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JOURNAL OF SCIENTIFIC COMPUTING 2024年第2期99卷 43-43页

作者： Zheng, Zi-Yun Wang, Yuan-Ming East China Normal Univ Sch Math Sci Key Lab Math & Engn Applicat Shanghai Key Lab Pure Math & Math PracticeMinist Shanghai 200241 Peoples R China

A two-dimensional time-fractional mobile-immobile diffusion problem with the Caputotime-fractional derivative of order alpha is an element of (0,1) is considered. We show that the solution of the problem has a weak singularity at the initial time. Using the averagedL1 formula to approximate the Caputo time-fractional derivative and using a compact finite difference approximation to discretize the space derivatives, we propose a high-order averaged L1-typecompact finite difference method on the uniform space-time mesh for the problem. We then base on this method to develop an averagedL1-type compact alternating direction implicit(ADI) finite difference method and a fast sum-of-exponentials compact ADI finite difference method, both of which significantly reduce the storage requirements and the computational costs while maintaining the same global convergence rate. By using the discrete energy analysis technique, we rigorously prove that all methods are unconditionally stable and convergent, and they have the spatial global fourth-order convergence rate and the temporal global convergence rate of order min{2,3-2 alpha}. For the case of alpha>1/2, we use the discrete minimum-maximum principle to prove that the temporal second-order convergence rate can also be achieved in positive time. Numerical results confirm the theoretical analysis results and demonstrate the computational efficiency of the methods.

关键词： Time-fractional mobile-immobile diffusion problem Weak singularity Compact ADI finite difference method fast algorithm Stability and convergence

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Research on fast Motion Estimation in H264 Coding 13

Research on Fast Motion Estimation in H264 Coding

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13th International Conference on Graphics and Image Processing (ICGIP)

作者： Jiao, Shengli Wang, Yunsen Luan, Li Yu, Xuelei Shandong Inst Space Elect Technol Yantai Peoples R China

ISBN: (数字)9781510650435

ISBN: (纸本)9781510650435;9781510650428

H.264 is an advanced video coding standard with wide application prospects. It has excellent compression performance and excellent image coding quality. It is widely used in many common fields such as video transmission, video storage and video editing. H. 264 uses a lot of complex computation, in which motion estimation takes up the largest amount of computation. Efficient motion estimation algorithm is of great significance to improve the efficiency of video coding. In this paper, the motion estimation and its typical algorithms of H.264 video coding standard are studied, focusing on UMHexagons (hereinafter referred to as UMH), the initial prediction order of motion vector and 5x5 spiral full search template is optimized, greatly improving the search efficiency.

关键词： Video compression motion estimation fast algorithm

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Rate-Distortion-Guided Learning Approach with Cross-Projection Information for V-PCC fast CU Decision 22

Rate-Distortion-Guided Learning Approach with Cross-Projecti...

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30th ACM International Conference on Multimedia (MM)

作者： Yuan, Hang Gao, Wei Li, Ge Li, Zhu Peking Univ Shenzhen Grad Sch Shenzhen Peoples R China Peng Cheng Lab Shenzhen Peoples R China Univ Missouri Kansas City Kansas City MO USA

ISBN: (纸本)9781450392037

In video-based point cloud compression (V-PCC), the 3D dynamic point cloud sequence is projected into 2D sequences for compression by utilizing the mature 2D video encoder. It is noted the encoding of attribute sequence is extremely time-consuming, and the applicable fast algorithms are still lacking because of the uniqueness of video content and coding structure in V-PCC. This paper proposes a novel rate-distortion-guided fast attribute coding unit (CU) partitioning approach with cross-projection information in VPCC all-intra (AI) coding. By analyzing the guidance effectiveness of cross-projection information for attribute CU partition, we first propose to combine the occupancy, geometry and attribute features for CU division determination. Afterward, considering that different CUs have different rate-distortion costs and the influences on coding performances by inaccurate different CU predictions are also dissimilar, we devise a rate-distortion-guided learning approach to reduce the coding loss generated by the mispredictions of CU partition. Moreover, we carefully design an overall decision framework for CU partition in V-PCC AI coding structure. Experimental results prove the advantages of our approach, where the coding time is saved by 62.41%, and the End-to-End BD-TotalRate loss only is 0.27%. To the best of our knowledge, the proposed fast attribute CU decision approach achieves the state-of-the-art performance in V-PCC AI coding.

关键词： V-PCC coding unit partition fast algorithm machine learning

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Deterministic algorithm and faster algorithm for Submodular Maximization subject to a Matroid Constraint 65

Deterministic Algorithm and Faster Algorithm for Submodular ...

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65th Symposium on Foundations of Computer Science

作者： Buchbinder, Niv Feldman, Moran Tel Aviv Univ Dept Stat & Operat Res Tel Aviv Israel Univ Haifa Dept Comp Sci Haifa Israel

ISBN: (纸本)9798331516758;9798331516741

We study the problem of maximizing a monotone submodular function subject to a matroid constraint, and present for it a deterministic non-oblivious local search algorithm that has an approximation guarantee of 1 - 1/e - epsilon (for any epsilon > 0) and query complexity of (O) over tilde (epsilon)(nr), where n is the size of the ground set and r is the rank of the matroid. Our algorithm vastly improves over the previous state-of-the-art 0.5008-approximation deterministic algorithm, and in fact, shows that there is no separation between the approximation guarantees that can be obtained by deterministic and randomized algorithms for the problem considered. The query complexity of our algorithm can be improved to (O) over tilde (epsilon)(n + r root n) using randomization, which is nearly-linear for r = O(root n), and is always at least as good as the previous state-of-the-art algorithms.

关键词： submodular maximization matroid constraint deterministic algorithm fast algorithm

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FPGA based Unified Architecture for H.266/VVC 1-D DCT-II Transform 7

FPGA based Unified Architecture for H.266/VVC 1-D DCT-II Tra...

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IEEE 7th International Conference on Advanced Technologies, Signal and Image Processing (ATSIP)

作者： Alshahrani, Jubran Loukil, Hassen King Khalid Univ Elect Engn Dept Coll Engn Abha 61413 Asir Saudi Arabia Univ Sfax Natl Sch Engn Elect & Informat Technol Lab Sfax 3038 Tunisia

ISBN: (纸本)9798350351491;9798350351484

In 2020, the cutting-edge video compression standard known as Versatile Video Coding (VVC) was introduced. Also referred to as VVC and H.266, this standard promises significant advancements in video compression technology. The VVC codec operates on a block-based hybrid model, boasting both complexity and capability. Employing a flexible block partitioning structure called Residual Quadtree (RQT), it utilizes three fundamental units: Coding Unit (CU), Prediction Unit (PU), and Transform Unit (TU), with transform unit sizes ranging from 2x2 to 64x64. Each transform size is computed using its designated matrix. This study proposes an FPGA-based implementation for the one-dimensional Discrete Cosine Transform (DCT-II) component of the Versatile Video Coding standard (VVC). A novel technique is introduced, utilizing the DCT-II transform unit to generate all other required sizes. By capitalizing on the symmetrical properties of DCT-II transform elements, a single transform matrix of 64x64 size is utilized across all sizes. This architecture seamlessly accommodates transform sizes ranging from 2x2 to 64x64. The design specifications have been articulated using very high-speed integrated circuit hardware description language (VHDL).

关键词： Versatile Video Coding (VVC) fast algorithm Core Transform Optimized Hardware Implementation

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