共查询到20条相似文献，搜索用时 531 毫秒
1.
通过对视频信号的帧内多普勒域导频估计,实现对视频编码无损传输,提高视频图像传输的保真度。传统方法中对视频编码的导频估计算法采用时域亮度均值重叠分块的奇异值分解方法,视频数据进行强制分片和分块重组,视频编码流出现糊分块效应,导致视频纠错效果不好。针对上述问题,提出一种改进的视频编码无损传输中帧内多普勒域导频估计算法。构建视频传输网络结构模型,进行丢包率预测,把实时视频可以看作多幅的彩色图像按一定时间间隔顺序进行刷新显示,使图像数据将其能量的大部分集中于频率域的一个小范围内,采用量化分析方法提取帧内视频压缩特征,进行视频编码无损传输中帧内多普勒域导频估计算法改进。仿真结果表明,该方法计算精度较高,提高了视频通信的图像保真度,降低了视频失真,提高了视频传输质量,具有较好的视频传输纠错性能。展示了优越性和较好的应用价值。 相似文献
2.
基于物联网的远程视频监控优化方法研究 总被引：1，自引：0，他引：1
《科技通报》2015,(10)
设计远程视频监控系统的关键是在于对视频图像的实时传输和数据通信设计,远程视频监控系统中接收端所显示的视频图像通常受到吞吐量和传输时延等因素的影响,导致远程视频监控实时性和保真性不好。提出一种基于物联网的远程视频监控优化方法。设计基于物联网的远程视频数据采集系统模型,构建远程视频监控识别的量化编码算法,使用RLE行程编码和Huffman编码来完成压缩任务,采用三级放大器进行逐级放大,进行远程视频监控。仿真结果表明,采用该方法进行远程视频监控,能准确实现对远程监控视频序列量化编码,提高远程视频监控的视频保真度和峰值信噪比,同时能提高视频传输效率,实现了视频远程监控的实时无损传输。 相似文献
3.
4.
5.
针对基于FPGA器件实现实时视频图像处理中原始视频数据与视频编码算法不兼容的问题,本文提出了一种离散缩放算法,通过它对原始图像进行预处理,能使图像缩放后仍具有自然分明的边界,达到较为理想的视觉效果,可以更好地通过FPGA器件进行后来的视频图像压缩。 相似文献
6.
对数字热成像的噪点信息矢量量化是实现图像去噪,提高图像识别能力的关键技术。传统方法中对数字热成像中噪点信息矢量量化算法采用LBG算法,当图像出现灰色关联度噪点时,量化算法的抗噪性能不好。提出一种基于强边缘保留和误差补偿编码的数字热成像中噪点信息矢量量化算法。用量化误差补偿法对量化的热成像进行补偿,消除当前图像块的瑕疵特征点,提高误差补偿编码处理精度。仿真表明,本算法对数字热成像噪点信息的矢量量化效果较好,去噪性能优越,进行矢量量化处理后,实现噪点去除,PSNR值较传统方法都有明显提高,提高对图像目标的识别性能,较传统方法优越。 相似文献
7.
《科技通报》2015,(8)
单帧视频实时传输技术广泛应用在多媒体远程教学等领域,传统方法采用差分编码DPCM调制方式进行单帧视频实时传输,量化步长重叠区域过多,且计算量较大。提出一种基于离散余弦变换的单帧视频实时传输技术,在关键帧获取过程中,获取RGB影像的同时,同步获取了该关键帧对应的相机位置参数,实时视频可以看作多幅的彩色图像按一定时间间隔顺序的行刷新显示,使用RLE行程编码,得到量化编码频谱特征,通过离散余弦变化,经过对图像数据的分包,图像信息已经被存放到相应的链表中,最后显示在屏幕上,实现单帧视频实时传输,提高了视频传输的实时性和保真性。仿真实验表明,该算法性能优越,在多媒体远程教学等领域具有较大的应用价值。 相似文献
8.
针对传统视频图像解码算法进行解码运算时,存在解码后视频图像失真率高、解码效率低的问题,提出基于边缘提取的会议视频图像快速解码算法.该算法采用边缘提取方法预处理会议视频图像,以获得会议视频图像的边缘掩膜,根据边缘掩膜对会议视频图像进行平滑处理.通过自适应抽帧方法增大视频图像中的序列场景,抽取未发生跳变的图像帧数.采用双向运动补偿插帧方法填充运动矢量,完成会议视频图像的快速解码.实验结果表明,所提出的基于边缘提取的会议视频图像快速解码算法,边缘提取误差低、解码失真率低、解码效率高,具有较高的实际应用价值. 相似文献
9.
10.
11.
《Information processing & management》2016,52(5):873-884
OCR errors in text harm information retrieval performance. Much research has been reported on modelling and correction of Optical Character Recognition (OCR) errors. Most of the prior work employ language dependent resources or training texts in studying the nature of errors. However, not much research has been reported that focuses on improving retrieval performance from erroneous text in the absence of training data. We propose a novel approach for detecting OCR errors and improving retrieval performance from the erroneous corpus in a situation where training samples are not available to model errors. In this paper we propose a method that automatically identifies erroneous term variants in the noisy corpus, which are used for query expansion, in the absence of clean text. We employ an effective combination of contextual information and string matching techniques. Our proposed approach automatically identifies the erroneous variants of query terms and consequently leads to improvement in retrieval performance through query expansion. Our proposed approach does not use any training data or any language specific resources like thesaurus for identification of error variants. It also does not expend any knowledge about the language except that the word delimiter is blank space. We have tested our approach on erroneous Bangla (Bengali in English) and Hindi FIRE collections, and also on TREC Legal IIT CDIP and TREC 5 Confusion track English corpora. Our proposed approach has achieved statistically significant improvements over the state-of-the-art baselines on most of the datasets. 相似文献
12.
This paper presents a simplified design methodology for robust event-driven tracking control of uncertain nonlinear pure-feedback systems with input quantization. All nonlinearities and quantization parameters are assumed to be completely unknown. Different from the existing event-driven control approaches for systems with completely unknown nonlinearities, the main contribution of this paper is to design a simple event-based tracking scheme with preassigned performance, without the use of adaptive function approximators and adaptive mirror models. It is shown in the Lyapunov sense that the proposed event-driven low-complexity tracker consisting of nonlinearly transformed error surfaces and a triggering condition can achieve the preselected transient and steady-state performance of control errors in the presence of the input quantization. 相似文献
13.
《Information processing & management》2023,60(3):103301
Hashing has been an emerging topic and has recently attracted widespread attention in multi-modal similarity search applications. However, most existing approaches rely on relaxation schemes to generate binary codes, leading to large quantization errors. In addition, amounts of existing approaches embed labels into the pairwise similarity matrix, leading to expensive time and space costs and losing category information. To address these issues, we propose an Efficient Discrete Matrix factorization Hashing (EDMH). Specifically, EDMH first learns the latent subspaces for individual modality through matrix factorization strategy, which preserves the semantic structure representation information of each modality. In particular, we develop a semantic label offset embedding learning strategy, improving the stability of label embedding regression. Furthermore, we design an efficient discrete optimization scheme to generate compact binary codes discretely. Eventually, we present two efficient learning strategies EDMH-L and EDMH-S to pursue high-quality hash functions. Extensive experiments on various widely-used databases verify that the proposed algorithms produce significant performance and outperform some state-of-the-art approaches, with an average improvement of 2.50% (for Wiki), 2.66% (for MIRFlickr) and 2.25% (for NUS-WIDE) over the best available results, respectively. 相似文献
14.
An experimental best match retrieval system is described based on the serial file organisation. Documents and queries are characterised by fixed length bit strings and the time-consuming character-by-character term match is preceeded by a bit string search to eliminate large numbers of documents which cannot possibly satisfy the query. Two methods, one fully automatic and one partially manual in character, are described for the generation of such bit string characterisations. Retrieval experiments with a large document test collection show that the two-level search can increase substantially the efficiency of serial searching while maintaining retrieval effectiveness, and that a single-level search based only upon the bit strings results in only a small decrease in effectiveness in some cases. 相似文献
15.
《Journal of The Franklin Institute》2021,358(13):6508-6525
For multi-agent system (MAS), most of existing iterative learning control (ILC) algorithms consider about the tracking of reference defined over the whole trial interval, while the point-to-point (P2P) task, where the emphasis is placed on the tracking of intermediate time points, has not been explored. Thus, a distributed ILC method is proposed, in which each agent updates the feedforward control input by learning from the experience of itself and its neighbors in previous repeated tasks to achieve the goal of improving performance. In addition, for the sake of reducing the burden of data transmission in MAS, effective data quantization is essential. In this case, the quantitative measurement of the error of the tracking time points is further used in the ILC updating law. In order to accommodate this requirement, a distributed point-to-point iterative learning control (P2PILC) with tracking error quantization for MAS is first proposed in this paper. A necessary and sufficient condition is presented for the asymptotical stability of the proposed algorithm, and simulation results show the effectiveness of it finally. 相似文献
16.
17.
《Journal of The Franklin Institute》2022,359(11):5733-5749
In this paper, the fault detection filter (FDF) design problem based on a dynamic event-triggered mechanism (DETM) is investigated for discrete-time systems with signal quantization and sensor nonlinearity. In order to conserve the limited network resources, a newly event-triggered mechanism with dynamic threshold is adopted to reduce the number of transmitted data through network more effectively. With the consideration of DETM, signal quantization and sensor nonlinearity, a fault detection filter is constructed to achieve the robustly asymptotic stability of established model with expected fault detection objective. In addition, by influence of DETM, external interference and quantization errors, a zonotopic residual evaluation mechanism is constructed to detect the occurring fault of plant. Finally, a practical example is provided to illustrate the effectiveness of proposed design approach. 相似文献
18.
《Journal of The Franklin Institute》2022,359(7):2886-2905
This paper investigates an observer-based sliding mode control (SMC)) for connected vehicles under denial-of-service attacks. The attacks refer to interrupting communication channels between vehicles. Firstly, a reduced order observer is used to estimate the relative acceleration between neighbor vehicles, and a switching communication topology is introduced to model the attack. Then, an observer based sliding mode controller is proposed to achieve desired stability performance. Moreover, a quadratic cost performance is also defined and the cost upper bound is proved. Some sufficient conditions are provided such that the connected vehicles can achieve robust tracking performance, and input-to-state string stability is guaranteed under zero initial errors. Finally, numerical simulations are given to illustrate the validity of the designed controller. 相似文献
19.
Dacai Liu Zhi Liu C.L. Philip Chen Yun Zhang 《Journal of The Franklin Institute》2021,358(3):1782-1811
The existing studies on prescribed-time control cannot directly deal with nonlinear functions which don’t satisfy Lipschitz growth conditions. No results are available for prescribed-time containment control of pure-feedback UNMASs with prescribed performance. Therefore, completely unknown nonlinear function, prescribed-time tracking of system states and prescribed performance of containment errors are simultaneously considered in this paper. Fuzzy logic systems are utilized to approximate completely unknown nonlinear function. Prescribed-performance function is introduced and further incorporated into a novel speed function. Combining the proposed speed function and barrier Lyapunov function, this article presents a novel adaptive fuzzy prescribed-time containment control method which can guarantee, under prescribed performance, all followers converge to a convex formed by dynamic leaders in a prescribed time. Moreover, all tracking errors converge to predefined regions in a prescribed time. The effectiveness of the proposed prescribed-time containment control method are confirmed by strict proof and simulation. 相似文献