QA活动的理解与实施

质量保证（QA）活动是软件能力成熟度（CMMI）实施中较难得到贯彻的过程。针对目前国内的QA过程实施情况,从QA的地位、原则、活动、实施等方面进行了阐述;同时讨论了QA与质量控制（QC）、测试之间的关系;以及实施QA活动的最佳实践,为组织实施过程改进提供了基础。     

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.     

底片检查机应用价值分析

底片检查机对PCB菲林质量检测具有重要的意义。随着PCB工艺的发展,传统的依靠人工目检已经不能满足菲林质量检测的需求。本文介绍了底片检查机的基本工作原理,根据底片检查机在PCB企业的成功应用,从品质控制、效率提高、节省人工、降低劳动强度、标准化生产等方面分析了底片检查机对PCB菲林质量检测工艺的重要价值。     

一种新的微机械陀螺品质因数测试方法

传统的微机械陀螺采用扫频方法测试结构的品质因数,存在耗时长、测量效率低和精度差等问题.提出了一种新的品质因数测量方法,该方法的原理是通过对陀螺的驱动端施加一个激励脉冲,采集驱动检测端的相应衰减信号,并通过处理得到衰减信号的频率和斜率,从而检测陀螺的品质因数.采用自行设计的激励电路,外购NI公司的高速采集卡和基于LabV...     

用于MEMS惯性器件的低噪声读出电路设计

给出了一种用于MEMS惯性器件的低噪声读出电路设计,针对MEMS惯性器件大多采用电容量输出等特点,设计了一个低噪声运算放大器,利用该运放,设计了一种基于开关电容的电荷转移电路来将电容量转换为电压量,以便后续电路处理.采用了相关双采样(CDS)技术,较大地减少了电路和MEMS惯性器件的1/f噪声、热噪声,抑制了零漂.采用HHNEC 0.35 μmCMOS工艺制造,面积为1 mm×2 mm,与MEMS器件封装在一起,并进行了实际测试,结果表明,该读出电路基本满足要求,并具有较低的噪声.     

接近零不合格过程的质量分析及控制探讨

该文对提高接近零不合格过程的质量分析和控制的准确性及效率进行探讨,提出对接近零不合格过程的质量分析首先应根据产品质量要求和过程能力要求选择合适的aσ,且要与接近零不合格过程的控制的程度相适应,然后利用传统的统计过程控翩(SPC)的方法对过程进行质量分析和控制,使过程处于受控状态或良好的受控状态,同时利用该状态时的不合格...     

低电压驱动的MEMS F-P可调光学滤波器研究

基于微机电系统（MEMS）技术,研制了一种新颖的光学腔与静电驱动器分离的Fabry-Pérot（F-P）可调谐滤波器。从光学设计、MEMS结构设计、制造工艺与器件测试等开展了F-P可调谐滤波器的研究,成功制备了工作在以1550 nm波长为中心、调谐范围为40 nm和驱动电压低于30 V的MEMS F-P可调滤波器。测试...     

Survey of information theory in visual quality assessment

We survey information theoretic approaches to solve a variety of visual quality assessment (QA) problems. These approaches are generally built on natural scene statistical models and lead to practical automatic QA algorithms delivering excellent performance in terms of correlation with human judgments of quality. We study all three categories of image QA models: full reference (FR), reduced reference (RR) and no reference (NR) image QA, as well as FR video QA and information weighting strategies for FR image and video QA. We demonstrate the application of information theory in each of these problems. Each of these problems presents its own challenges in the design of information theoretic QA indices leading to different algorithms under different scenarios. In the algorithms, we survey, FR image and video QA algorithms are based on mutual information or conditional Kolmogorov complexities; RR image QA algorithms either use relative entropy or entropic differences, while the NR QA algorithm applies Rényi entropy, and the weighting strategies rely on mutual information. We also discuss various open research questions, particularly in the realm of NR image QA and all classes of video QA.     

MEMS可变电容的研究现状及进展

介绍了微机电系统(MEMS)技术以及MEMS可变电容器,基于MEMS的可变电容具有高Q值、低损耗、宽调节范围和低噪声等优点,阐述了MEMS可变电容器设计的基本原理,列举了现有的几种典型结构模型。通过指定频率下Q值及调谐范围的具体数值,比较不同结构的MEMS可变电容的特点,展望了MEMS可变电容的发展并得出结论。     

MEMS惯性传感器可靠性试验方法研究

MEMS惯性传感器在军事与商业应用中的一个主要问题便是可靠性试验方法尚未标准化,因而目前绝大多数MEMS惯性传感器器件的可靠性试验依据的是傲电子的试验标准。但是,这些标准对于这类器件的适用性却受到许多机构的质疑,国外关于该问题的研究也已起步。汇总了MEMS惯性传感器器件的结构和工作原理等信息,重点总结了该类器件的典型环境失效机理,并将典型的环境载荷情况与失效机理进行了对比分析：从现有的微电子可靠性试验标准中选取了针对不同环境失效机理的试验方法。并对其适用性问题进行了讨论。     

Microelectromechanical systems and system-on-chip connectivity

The interconnection of microelectromechanical systems (MEMS) and other devices to a system-on-chip (SoC) implementation is described. MEMS technology can be used to fabricate both application specific devices and the associated micropackaging system that will allow for the integration of devices or circuits, made with non-compatible technologies, with a SoC environment. In the primary example presented, MEMS technology has been used to develop an acoustical array sensor for a hearing instrument application and also to provide a custom micropackaging solution suitable for in-the-ear canal implantation. A MEMS based modular micropackaging solution consisting of MEMS socket submodules and an insertable/removable microbus card has been developed to provide the necessary packaging and connectivity requirements. The modular socket concept can also be used for many other purposes, such as temporarily connecting a CMOS die to a SoC implementation of a die tester using MEMS based cantilevered bridge-type microspring contacts to provide connectivity to the die under test.     

Simultaneous Quality and Reliability Optimization for Microengines Subject to Degradation

Micro-Electro-Mechanical Systems (MEMS) represent an exciting new technology, but to achieve more widespread usage and wider adoption within more industrial applications, they must be highly reliable, and manufactured to stringent quality standards. Many challenging manufacturing issues are of concern during the fabrication of MEMS, such as precise dimensional inspection, reliability modeling, burn-in scheduling, avoiding stiction, and maintenance strategies. However, only limited mathematical tools for improving MEMS reliability, quality, and productivity are currently available. This paper proposes a mathematical model to jointly determine inspection & preventive replacement policies for surface-micromachined microengines subject to wear degradation, which is a major failure mechanism for certain MEMS devices. The optimal specification limits for inspection, and the replacement interval are determined by simultaneously optimizing MEMS quality and reliability. The proposed model can be used as a tool for decision-makers in MEMS manufacturing to make sound economical and operational decisions on reliability, quality, and productivity. While illustrated considering one specific microengine design, the proposed model can be applied to a broader range of MEMS devices that experience wear degradation between rubbing surfaces.      

MEMS薄膜材料参数在线测试方法与技术

给出了一种MEMS薄膜材料参数的在线测试技术与方法.这种技术包括微测试结构图形、测试硬件设备和测试分析软件.它能够快速测试MEMS薄膜的主要性能参数,并且测试设备和测试方法都与集成电路测试方案兼容,即所有材料参数的测试与提取都通过电学激励与电学测量来实现.文中首先给出了测试技术与方法的工作原理,然后对用标准表面微机械加工工艺制作的多晶硅薄膜进行了测试,实验结果表明该测试技术与方法的测试效率高、成本低,具有一定的工业应用价值.     

MEMS及微机械加速度计可靠性研究

由于MEMS器件的应用日益频繁,其可靠性研究就显得十分重要。介绍了引起可靠性问题的原因。以微机械加速度计为例,指出了该加速度计的可靠性问题,以及对其可靠性测试研究的内容。     

A highly simple failure detection method for electrostatic microactuators: application to automatic testing and accelerated lifetime estimation

Reliability and testability are two important factors for the development of batch fabrication of microelectromechanical systems (MEMS) or mixed MEMS/IC applications. In that frame, an easy-to-implement electrical method of detection of failures is presented in this paper, valid for every kind of electrostatic microactuators showing pull-in behavior, with great expectation value in the case of arrayed MEMS. The method relies on the detection of a pull-in current peak at very low frequency. An experimental setup is described and results are shown obtained with prototypes of electrostatic microactuators with parallel capacitances created by deep reactive ion etching on silicon-on-insulator wafers. This method is really suitable for automation and application to on-line testing during mass production and reliability studies. The functional schematic of a test circuitry is proposed for implementation in an industrial tester or for built-in self-test purposes. Then, in order to illustrate the benefits of this method for reliability studies, it is used in conjunction with high voltage testing for accelerated lifetime measurements. A time gain factor of 20 is achieved with above-mentioned test structures.     

射频MEMS压控电容器

研究了射频 MEMS压控电容器的设计和制造工艺。压控电容器的制作采用了 MEMS制造技术 ,其主要结构为硅衬底上制作金属传输线电极和介质层 ,然后制作金属膜桥作为电容器的另一个电极。通过改变加在金属膜桥与传输线间的电压达到改变电容值的目的。这种压控电容器可以工作于射频和微波波段 ,具有很高的Q值。测试结果如下 :在 1 GHz、0 V时 Q值达到 3 0 0 ,0偏压电容值为 0 .2 1 p F,当加上驱动电压后 Cmax/ Cmin的变比约为 4∶ 1     

MEMS薄膜磁学特性的在线测试结构

为了能实时监控MEMS器件的一些重要指标,人们对器件包括热导率,断裂强度等材料的属性进行了深入研究。由于MEMS磁学特性的复杂性,对MEMS磁学特性在线测量研究得很少。本文分析了具有代表性的薄膜磁学特性测试结构的原理及优缺点,并结合MEMS在线测试的特点提出了一种比较适合MEMS在线测试的新结构。     

No-reference quality assessment using natural scene statistics: JPEG2000.

Measurement of image or video quality is crucial for many image-processing algorithms, such as acquisition, compression, restoration, enhancement, and reproduction. Traditionally, image quality assessment (QA) algorithms interpret image quality as similarity with a "reference" or "perfect" image. The obvious limitation of this approach is that the reference image or video may not be available to the QA algorithm. The field of blind, or no-reference, QA, in which image quality is predicted without the reference image or video, has been largely unexplored, with algorithms focusing mostly on measuring the blocking artifacts. Emerging image and video compression technologies can avoid the dreaded blocking artifact by using various mechanisms, but they introduce other types of distortions, specifically blurring and ringing. In this paper, we propose to use natural scene statistics (NSS) to blindly measure the quality of images compressed by JPEG2000 (or any other wavelet based) image coder. We claim that natural scenes contain nonlinear dependencies that are disturbed by the compression process, and that this disturbance can be quantified and related to human perceptions of quality. We train and test our algorithm with data from human subjects, and show that reasonably comprehensive NSS models can help us in making blind, but accurate, predictions of quality. Our algorithm performs close to the limit imposed on useful prediction by the variability between human subjects.     

Fabrication of integrated metallic MEMS devices

A simple and complementary metal oxide semiconductor (CMOS) compatible fabrication technique for microelectromechanical (MEMS) devices is presented. The fabrication technology makes use of electroplated metal layers. Among the fabricated devices, high quality factor microresonators are characterised with respect to the quality factor.     

An information fidelity criterion for image quality assessment using natural scene statistics.

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. Traditionally, image QA algorithms interpret image quality as fidelity or similarity with a "reference" or "perfecft" image in some perceptual space. Such "full-referenc" QA methods attempt to achieve consistency in quality prediction by modeling salient physiological and psychovisual features of the human visual system (HVS), or by arbitrary signal fidelity criteria. In this paper, we approach the problem of image QA by proposing a novel information fidelity criterion that is based on natural scene statistics. QA systems are invariably involved with judging the visual quality of images and videos that are meant for "human consumption." Researchers have developed sophisticated models to capture the statistics of natural signals, that is, pictures and videos of the visual environment. Using these statistical models in an information-theoretic setting, we derive a novel QA algorithm that provides clear advantages over the traditional approaches. In particular, it is parameterless and outperforms current methods in our testing. We validate the performance of our algorithm with an extensive subjective study involving 779 images. We also show that, although our approach distinctly departs from traditional HVS-based methods, it is functionally similar to them under certain conditions, yet it outperforms them due to improved modeling. The code and the data from the subjective study are available at.