环境一号卫星CCD影像质量评价研究

从图像工程质量评价和影像应用质量评价两个方面,对环境一号卫星CCD影像的质量进行了评价与分 析,通过将其与同时相Landsat TM影像的相关特征参数进行比较,客观评价了环境一号卫星CCD影像的质量。图像工程质量评价从影像的 统计特征、纹理特征和能量特征三方面进行,结果表明该卫星影像能够提供地物目标的形状、细节、纹理特征;影像应 用质量评价则是通过将该卫星影像应用于北京市城市绿地信息提取的具体工作来进行的,结果表明该卫星影像的 绿地信息提取精度较高,总分类精度达到84.45%,适用于城市绿地信息的提取。     

基于单频时变阈值的1-bit SAR成像方法研究

该文提出一种基于单频时变阈值的1-bit合成孔径雷达(SAR)成像方法,通过将回波数据与时变阈值比较,将其量化为1-bit采样数据,从而降低SAR回波数据的位宽,达到简化系统、提升效率的目的。传统的1-bit采样将信号与0阈值比较,这将造成信号相对幅度的非线性失真,影响成像质量。而随机时变阈值虽然能够保留幅度信息,却会引入额外的类噪声干扰。单频时变阈值将能够有效地保留1-bit采样量化中丢失的相对幅度信息,同时避免引入类噪声干扰,有效地提高了1-bit采样量化下的SAR成像质量。通过仿真实验定量分析了算法的成像聚焦质量、幅度信息保持能力,并通过对场景目标的成像验证了算法的有效性。      

RRED indices: reduced reference entropic differencing for image quality assessment

We study the problem of automatic "reduced-reference" image quality assessment (QA) algorithms from the point of view of image information change. Such changes are measured between the reference- and natural-image approximations of the distorted image. Algorithms that measure differences between the entropies of wavelet coefficients of reference and distorted images, as perceived by humans, are designed. The algorithms differ in the data on which the entropy difference is calculated and on the amount of information from the reference that is required for quality computation, ranging from almost full information to almost no information from the reference. A special case of these is algorithms that require just a single number from the reference for QA. The algorithms are shown to correlate very well with subjective quality scores, as demonstrated on the Laboratory for Image and Video Engineering Image Quality Assessment Database and the Tampere Image Database. Performance degradation, as the amount of information is reduced, is also studied.     

VoIP over cdma2000 1xEV-DO revision A

In this article we analyze performance of VoIP services over 1xEVDO-Revision A (DO-Rev A) networks and show that high-quality VoIP with unconstrained mobility and high capacity can be achieved. Together with quality of service (QoS) requirements, we emphasize practical issues such as mobility, degradation of feedback-channel quality, and packet overheads. Novel techniques are presented for voice processing such as smart blanking and adaptive dejitter playback buffer with time warping. These techniques help to meet QoS constraints to achieve a circuit-like voice quality while improving overall capacity. Detailed end-to-end simulations are presented and system capacity is analyzed under the QoS and system stability constraints. We claim that DO-Rev A can provide VoIP capacity comparable to circuit-switched cellular CDMA technologies (e.g., IS-2000) and simultaneously carry significant amount of other types of traffic such as non-delay sensitive applications and downlink multicast.     

一个图像质量盲评估的统计测度

本文提出了一个图像质量盲评估的统计测度.该测度首先根据自然图像的统计性质与失真图像的模型,实现对图像小波系数分布参数的盲估计;再利用估计的分布参数来计算失真图像与参考图像之间的互信息,以量化失真图像对参考图像的保真度,进而实现对图像质量的评估.本文提出的测度避免了对参考图像的依赖,且克服了现有图像质量盲评估对特征选择与提取、机器学习等过程的依赖.LIVE图像质量评估数据库的总体评估结果表明：本文提出的盲评估统计测度对图像质量评估结果与数据库的主观评估结果高度一致,且优于文献中报道的盲评估测度.     

一种用于WI语音编码的相位预测式矢量量化方法

在传统的低比特率语音编码中,考虑到人耳对相位信息不敏感而经常忽略相位信息,这将导致语音粗糙、刺耳甚至音调发生改变。为了获得高质量的声码器,语音的相位信息是不能不考虑的。该文在散布相位矢量量化方法的基础上进一步去除了相位冗余,在波形内插(Waveform Interpolation,WI)编码模型中对相邻帧慢渐变波形(Slowly Evolving Waveform,SEW)的相位谱差值进行预测式矢量量化。实验发现,该方法大大改善了重建语音效果,明显提高了语音的自然度和清晰度。主观A/B测试结果显示,该方法与固定相位法相比,经4~6 bit的相位量化可使合成语音质量得到显著的改善,相比散布相位矢量量化方法,女声的语音合成质量有所改进。     

具有快速锁定时间的新型低相噪频率合成技术

介绍了一种新型频率合成器的基本原理和方法,该结构利用常规合成器中存在而被忽略的有用信息而改进的电路结构,捕捉速度快(＜20ms)、相位噪声低,与常规锁相频率合成器相比,相位噪声减小约25dB,可为现代通信提供纯净的频谱、较低的辐射和高质量的信息传送,大大提高了无线通信的质量和性能.     

A new reduced reference metric for color plus depth 3D video

A new reduced reference (RR) objective quality metric for 3D video is proposed that incorporates spatial neighboring information. The contrast measures from gray level co-occurrence matrices (GLCM) for both color and depth sections are main parts of spatial information. Side information is extracted from edge properties of reference 3D video and sent through an auxiliary channel. The other important factor in the proposed metric is the unequal weight of color and depth sections, which can maximize the performance of the proposed metric for some specific values. Performance of the proposed metric is validated through series of subjective tests. For validations, compression and transmission artifacts are considered. The average correlation of the proposed metric and subjective quality scores is 0.82 for compressed 3D videos when color to depth importance ratio is near 0.8. This measure for transmitted 3D videos is 0.857 for the same value of color to depth importance ratio.     

基于高增益接收系统的Galileo E1信号质量评估方法研究

Galileo系统在E1频点采用Interplex调制方式播发导航信号,由于缺乏E1信号功率分配和伪码序列等先验信息,一般的研究人员只能开展有限的信号质量特性研究.针对该问题,提出一套基于高增益天线的空间信号质量评估方法,实现了E1授权信号的解析,完善了E1信号评估体系.运用相关功率法来解决信号分量功率比问题,采用跟踪结果解决相位偏差估计问题,提出加权组合平均和码相位平均相结合的新型时域波形分离方法,克服了电文和码多普勒对时域波形特性评估的影响,采用S曲线过零点偏差（S-curve offset Biases,SCB）等参数进行信号测距偏差定量评估.通过该方法对Galileo GSAT-0214卫星进行了评估,结果显示：该卫星E1各信号分量SCB小于0.2ns,测距性能优异,其复用效率达到了97.8%,优于GPS L1信号和北斗三号系统（BDS-3） B1信号.     

Two-tier DPCM codec for videoconferencing

A two-tier differential pulse-code modulation (DPCM) codec for videoconference applications is described that utilizes the so-called masking effect of motion. In this approach, an image is separated into high-frequency and low-frequency components. The low-frequency signal is processed by an adaptive spatiotemporal DPCM codec. A motion indicator derived from the low-frequency signal is used to control the corresponding block of high-frequency component pixels. The system is aimed at adaptively removing the high-frequency component of an image in those areas which contain motion. Since less information is needed to be sent, the data rate is lower. Since the missing high-frequency information occurs only in moving areas, the human eyes are less likely to notice. In this way, the data rate is lowered without unduly giving up on the subjective image quality. Simulation results have shown that the amount of visible degradation in image quality is small while the reduction in data rate is substantial     

Forward high-speed wireless packet data service in IS-2000 - 1/spl times/EV-DV

This article describes enhancements to the physical layer design of single-carrier (1/spl times/) cdma2000/sup /spl reg// wireless networks introduced by Revision C of the IS-2000 standard (commonly referred to as 1/spl times/EV-DV). These improvements are mainly for the support of high-speed wireless packet data service on the forward (base station to mobile station) link. A new shared channel, the forward packet data channel, F-PDCH, is introduced to significantly increase spectral efficiency. This is accomplished through smart, channel-dependent scheduling of base station, BS, resources by taking advantage of the delay-tolerant nature of data traffic. This shared channel utilizes fast link adaptation through adaptive modulation and coding supported by the feedback of channel quality information. A form of hybrid ARQ type II technique commonly referred to as asynchronous adaptive incremental redundancy compensates for frame error events due to imperfect link adaptation. The impact of the new channel on voice capacity of the system is designed to be minimal because the F-PDCH utilizes resources that are not consumed by real-time users.     

BGT: A blind image quality evaluator via gradient and texture statistical features

Blind image quality assessment (BIQA) aims to design a model that can accurately evaluate the quality of the distorted image without any information about its reference image. Previous studies have shown that gradients and textures of image is widely used in image quality evaluation tasks. However, few studies used the joint statistics of gradient and texture information to evaluate image quality. Considering the visual perception characteristics of the human visual system, we develop a novel general-purpose BIQA model via two sets of complementary perception features. Specifically, the joint statistical histograms of gradient and texture are extracted as the first set of features, and the second set of features is extracted using the local binary pattern (LBP) operator. After extracting two groups of complementary quality-aware features, the feature vectors are sent to the support vector regression machine to establish the nonlinear relationship between quality-aware features and quality scores. A large number of experiments on seven large benchmark databases show that the proposed BIQA model has higher accuracy, better generalization properties and lower computational complexity than the relevant state-of-the-art BIQA metrics.     

基于AlxGa1-xN/InyGa1-yN DBR谐振腔的单片集成白光LED

本文设计和研究了含有蓝光和黄光两个量子阱有源区的单片集成白光发光二极管(LED)。为了提高黄光在混合光中的比例,我们采用AlxGaN1-x/InyGa1-yN 分布式布拉格反射镜(DBR)构成谐振腔对黄光的提取效率进行加强以增大其出射光功率。模拟结果表明,优化设计的谐振腔LED有利于得到高品质白光出射。     

Image information and visual quality.

Measurement of visual quality is of fundamental importance to numerous image and video processing applications. The goal of quality assessment (QA) research is to design algorithms that can automatically assess the quality of images or videos in a perceptually consistent manner. Image QA algorithms generally interpret image quality as fidelity or similarity with a "reference" or "perfect" image in some perceptual space. Such "full-reference" QA methods attempt to achieve consistency in quality prediction by modeling salient physiological and psychovisual features of the human visual system (HVS), or by signal fidelity measures. In this paper, we approach the image QA problem as an information fidelity problem. Specifically, we propose to quantify the loss of image information to the distortion process and explore the relationship between image information and visual quality. QA systems are invariably involved with judging the visual quality of "natural" images and videos that are meant for "human consumption." Researchers have developed sophisticated models to capture the statistics of such natural signals. Using these models, we previously presented an information fidelity criterion for image QA that related image quality with the amount of information shared between a reference and a distorted image. In this paper, we propose an image information measure that quantifies the information that is present in the reference image and how much of this reference information can be extracted from the distorted image. Combining these two quantities, we propose a visual information fidelity measure for image QA. We validate the performance of our algorithm with an extensive subjective study involving 779 images and show that our method outperforms recent state-of-the-art image QA algorithms by a sizeable margin in our simulations. The code and the data from the subjective study are available at the LIVE website.     

互补色小波域图像质量盲评价方法

图像色彩空间的RGB通道具有密切的关系,图像质量的改变会改变这样的关系.然而传统图像质量评价方法大多基于灰度图像统计特性,忽略了颜色通道间关系信息.为充分利用颜色信息,本文基于新近提出的互补色小波变换提出一种图像质量盲评价方法.文章建立了图像互补色域自然场景统计、多尺度和方向性能量分布等模型.分析表明：这些模型不仅涵盖了传统灰度方法所能描述的信息,而且还能借助于互补色来有效表示彩色图像各通道之间的信息联系,提供表征图像质量的一组高效特征.基于这些特征,我们提出的图像质量盲评价的方法能有效提取图像的失真统计特征,能给出与人眼主观评价图像质量结果保持高度一致、优于现有文献报道盲方法、且可与非盲（全参考）方法相比拟的评价结果.     

远程遥控驾驶场景下基于网络信息开放的QoS预测

5G系统的飞速发展支持许多车联网用例对服务质量（quality of service,Qo S）的苛刻要求。但网络和应用的适配仍然存在很多问题。网络信息开放是一种潜在的解决方案,旨在实现网络向应用程序实时提供蜂窝无线网络信息,从而帮助服务提供方实现更好的策略控制并改善用户体验。提出一种基于网络信息开放的服务质量预测（predictive QoS,PQo S）方法,通过提前预测即将发生的网络变化来支持应用做出提前响应,提高用户的体验质量（qualityofexperience,Qo E）。介绍了网络信息开放及PQo S的背景,并介绍了PQo S的国内外研究、标准及落地现状;提出一种远程遥控驾驶（tele-operateddriving,To D）场景下基于网络信息开放的Qo S预测方法;对实际测试的数据进行分析,评估验证了PQo S的可行性。结果表明,基于网络信息开放的Qo S预测技术能够良好地支持包括5G ToD在内的车联网应用,为5G系统在智慧交通行业的落地提供了参考。     

Monolithic white LED based on AlxGa1-x N/InyGa1-yN DBR resonant-cavity

A monolithic white light-emitting diode (LED) with blue and yellow light active regions has been de-signed and studied. With the AlxGa1-xN/InyGa1-yN distributed Bragg reflector (DBR) resonant-cavity, the extraction efficiency and power of the yellow light are enhanced so that high quality white light can be obtained.     

Transformation of a health care information system: aself-assessment survey

US health care providers are seeking to reduce costs while simultaneously maintaining quality of care. One strategy for the reinvention of the health care industry is the more effective use of new quality and information technology solutions. Results are presented from a survey of 98 top executives at Baylor Health Care System (BHCS), a large, multifunction health care organization in Dallas, TX. The survey sought to assess the executives' perceptions of current BHCS quality practices. The study used a survey developed for the health care industry based on the Malcom Baldrige National Quality Award (MBNQA) criteria. This paper reports findings related to the quality of BHCS internal and external data and information quality. Factor analysis and regression models using the survey data were used to highlight findings that include: (1) the need for a $50+ million information system transformation at BHCS as an essential action item to achieve the organization's critical success factors, and (2) the importance of internal and external data and information in achieving business process redesign and a quality transformation at BHCS. Results highlight the need for further research investigating the dimensions associated with the MBNQA criteria and their relationship with the information and analysis component     

Stereoscopic image quality assessment considering visual mechanism and multi-loss constraints

In this paper, a convolutional neural network (CNN) with multi-loss constraints is designed for stereoscopic image quality assessment (SIQA). A stereoscopic image not only contains monocular information, but also provides binocular information which is as identically crucial as the former. So we take the image patches of left-view images, right-view images and the difference images as the inputs of the network to utilize monocular information and binocular information. Moreover, we propose a method to obtain proxy label of each image patch. It preserves the quality difference between different regions and views. In addition, the multiple loss functions with adaptive loss weights are introduced in the network, which consider both local features and global features and constrain the feature learning from multiple perspectives. And the adaptive loss weights also make the multi-loss CNN more flexible. The experimental results on four public SIQA databases show that the proposed method is superior to other existing SIQA methods with state-of-the-art performance.     

MLSIM: A Multi-Level Similarity index for image quality assessment

Image quality assessment (IQA) is of great importance to numerous image processing applications, and various methods have been proposed for it. In this paper, a Multi-Level Similarity (MLSIM) index for full reference IQA is proposed. The proposed metric is based on the fact that human visual system (HVS) distinguishes the quality of an image mainly according to the details given by low-level gradient information. In the proposed metric, the Prewitt operator is first utilized to get gradient information of both reference and distorted images, then the gradient information of reference image is segmented into three levels (3LSIM) or two levels (2LSIM), and the gradient information of distorted image is segmented by the corresponding regions of reference image, therefore we get multi-level information of these two images. Riesz transform is utilized to get corresponding features of different levels and the corresponding 1st-order and 2nd-order coefficients are combined together by regional mutual information (RMI) and weighted to obtain a single quality score. Experimental results demonstrate that the proposed metric is highly consistent with human subjective evaluations and achieves good performance.