Angularly continuous light‐field format: Concept,implementation, and evaluation

In this paper, we present the concept, the implementation, and the evaluation of our novel angularly continuous light‐field format. We compared the subjective visual performance of our format with the perspective camera format through a series of subjective and objective tests. In our extensive subjective study, we used multiple absolute and comparative rating scales and various visual stimuli with different contents and angular resolutions. The perceived quality was assessed by a total of 36 test participants, who were separated based on their scientific expertise. The objective quality was evaluated through the degradations caused by three well‐known compression methods. The obtained results indicate that our light‐field format may outperform the conventional format, and it generally can provide at least equivalent visual quality. Furthermore, these findings open the way for data size optimization, without compromising the achieved level of perceived quality.     

Evaluation of Objective Quality Measures for Speech Enhancement

In this paper, we evaluate the performance of several objective measures in terms of predicting the quality of noisy speech enhanced by noise suppression algorithms. The objective measures considered a wide range of distortions introduced by four types of real-world noise at two signal-to-noise ratio levels by four classes of speech enhancement algorithms: spectral subtractive, subspace, statistical-model based, and Wiener algorithms. The subjective quality ratings were obtained using the ITU-T P.835 methodology designed to evaluate the quality of enhanced speech along three dimensions: signal distortion, noise distortion, and overall quality. This paper reports on the evaluation of correlations of several objective measures with these three subjective rating scales. Several new composite objective measures are also proposed by combining the individual objective measures using nonparametric and parametric regression analysis techniques.     

决策形式背景框架下证据推理模型研究

针对证据理论在决策过程中存在的证据获取困难、证据重要性不同等问题,在决策形式背景框架下构建了一种融合客观数据和先验知识的证据推理模型。该模型将决策形式背景的每个条件属性作为一条证据,同时对决策形式背景所蕴含的知识进行证据提取,获得基本信度指派函数,引入证据权重对合成公式进行修正。仿真结果和相关分析表明,所提方法是合理且有效的。     

一种基于视觉兴趣性的图象质量评价方法

图象质量的正确评价是图象信息工程领域内一项很有意义的研究课题,但现有的图象客观评价方法并不完全符合人眼视觉特性。合理地评价图象质量应充分遵循人眼的视觉特性,但由于受到人的心理、文化背景、周围环境、不同的应用场合等多种因素的影响,人眼对同一幅图象中的不同区域往往具有不同的感兴趣程度,即人眼具有视觉兴趣性特性,该文在充分利用视觉兴趣性特性的基础上,针对只存在一个感兴趣区的图象,提出了一种简化的图象质量     

Objective Speech Quality Estimation for Analog Mobile Channels: Problems and Solutions

This article describes an objective speech quality assessment method developed for the Hungarian NMT-450 cellular mobile telephone system. The method is based on a psychoacoustic front end followed by a cognitive modeling component. Special problems of the NMT system, such as handover (HOV), the effects of automatic gain control (AGC), and the intrusion of signaling noise, are addressed in the cognitive module. Correlation between the subjective and objective quality measures is maximized by finding a transformation that linearizes their relationship. A correlation of 0.95 is achieved on an independent test set between the subjective speech quality and the proposed objective quality measure.     

Watermarked 3-D Mesh Quality Assessment

This paper addresses the problem of assessing distortions produced by watermarking 3D meshes. In particular, a new methodology for subjective evaluation of the quality of 3D objects is proposed and implemented. Two objective metrics derived from measures of surface roughness are then proposed and their efficiency to predict the perceptual impact of 3D watermarking is assessed and compared with the state of the art. Results obtained show good correlations between the proposed objective metrics and subjective assessments by human observers     

Subjective tests for image fusion evaluation and objective metric validation

This paper focuses on the methodology for perceptual image fusion assessment through comparative tests and validation of objective fusion evaluation metrics. Initially, the theory of subjective fusion evaluation, adopted practice and methods to gauge relevance and significance of individual trials are examined. Further in this context, the methodology, experiences and results of a series of specific, subjective preference tests aimed at relative evaluation of fusion algorithms are presented. Test conditions and experimental procedure are described in detail and a number of explicit fusion metrics derived from the subjective test data are proposed. Relative fusion quality, fusion performance robustness (to content) and personal preference are all assessed by the metrics as different aspects of general image fusion performance. Finally, the methodology for subjective validation of objective fusion metrics using the reported test procedures is presented. In particular, explicit subjective–objective validation algorithms are defined and applied to a range of established objective measures of fusion performance in order to evaluate their subjective relevance.     

基于客观参数的图像质量评估

图像质量评价采用小波变换把自然图像分解成十个子带,在每个子带中设置两个参数和两个Logistic函数.通过计算客观度量与主观评估测试结果之间的关系来定义两个基于感知的模型,评估测试在包含344幅JPEG和JPEG2000图像的数据库中进行.线性预测模型能够反映图像的真实主观评分,而相关预测模型则能用来区分图像间的相对质量.在这两个模型中,每个客观参数和主观感知特性的关系用两个Logistic函数逼近,从而获得每个参数的最佳估计缺损程度.最终的图像质量度量通过组合各个估计缺损程度获得.实验表明这两种模型性能优良,和主观感知的图像质量有很强的相关性.     

Making the best of legacy video on modern displays

Abstract— The recent revolution in display technology enables bright high‐resolution displays, thereby removing one of the bottlenecks in video quality. How to profit from HD flat‐panel displays when watching legacy SD‐video material will be discussed. An overview of resolution up‐conversion techniques will be presented, including an objective (MSE‐scores) and a subjective assessment. Screenshots are also included to illustrate the quality of the algorithms.     

Toward robust and quantifiable automated IFC quality validation

The use of IFC as a standard format in exchange processes has been increasing as the industry begins to address the need of interoperability. A current problem with the use of IFC is in the quality of product models. Much effort has addressed this issue in the form of certifications to ensure a minimum quality of exchange requirements for an IFC file. However, even with the recent increasing awareness and effort to improve the quality of IFC files, the process is still too tedious, time consuming and requires manual efforts by experts. Even if those resources are available, there is currently no clear and quantifiable definitions of what exactly is a good quality IFC file. Without such measures, the adoption of IFC as standard exchange format will be hindered and the industry will be left with only restricted alternatives that are mostly vendor dependent. This paper sets out to address this issue in two aspects: first by defining what a good quality IFC model is, and second by proposing rules that can be automated to measure with confidence the completeness and correctness of the IFC model. These two aspects will serve as a starting point toward a more comprehensive and quantifiable measures of the quality of an IFC file. This proposed goal is represented by using well defined and well documented rules collected from various projects the authors had experienced over the years. The rules include all known aspects of IFC, including geometry, which currently requires mostly manual validation. The paper also proposes a method to address import validation that is under-developed compared to the export validation.     

Development of syllable-based text to speech synthesis system in Bengali

This paper presents the design and development of unrestricted text to speech synthesis (TTS) system in Bengali language. Unrestricted TTS system is capable to synthesize good quality of speech in different domains. In this work, syllables are used as basic units for synthesis. Festival framework has been used for building the TTS system. Speech collected from a female artist is used as speech corpus. Initially five speakers’ speech is collected and a prototype TTS is built from each of the five speakers. Best speaker among the five is selected through subjective and objective evaluation of natural and synthesized waveforms. Then development of unrestricted TTS is carried out by addressing the issues involved at each stage to produce good quality synthesizer. Evaluation is carried out in four stages by conducting objective and subjective listening tests on synthesized speech. At the first stage, TTS system is built with basic festival framework. In the following stages, additional features are incorporated into the system and quality of synthesis is evaluated. The subjective and objective measures indicate that the proposed features and methods have improved the quality of the synthesized speech from stage-2 to stage-4.     

Visual quality of high‐contrast projection screens. Part I: Visibility of screen‐based artifacts and noise

Abstract— The investigation of visual‐quality issues for high‐contrast projection screens such as those used for avionics projection displays and other applications requiring a high level of ambient light rejection will be described. Visibility of artifacts and noise generated by the optical and structural properties of a variety of high‐contrast projection screens was characterized by both empirical, subjective image quality evaluations and a suite of objective screen‐quality metrics. At least two of these metrics were found to provide very good correlation with the subjective assessment. These metrics are applicable to any display system where spatial‐noise artifacts are an issue, such as with direct‐view AMLCDs with anti‐glare treatments.     

Pervasive and standalone computing: the perceptual effects of variable multimedia quality

The introduction of multimedia on pervasive and mobile communication devices raises a number of perceptual quality issues; however, limited work has been done examining the three-way interaction between use of equipment, quality of perception and quality of service. Our work measures levels of informational transfer (objective) and user satisfaction (subjective) when users are presented with multimedia video clips at three different frame rates, using four different display devices, simulating variation in participant mobility. Our results will show that variation in frame rate does not impact a user's level of information assimilation, however, does impact a users’ perception of multimedia video ‘quality’. Additionally, increased visual immersion can be used to increase transfer of video information, but can negatively affect the users’ perception of ‘quality’. Finally, we illustrate the significant affect of clip-content on the transfer of video, audio and textual information, placing into doubt the use of purely objective quality definitions when considering multimedia presentations.     

Does social capital pay off? The case of small business resilience after Hurricane Katrina

This article uses objective and subjective measures of small business resilience and multiple categories of social capital pay‐offs to answer two main questions. Does social capital pay off after a natural disaster; and if it does, what type of social capital has the greatest impact on small business resilience? The pay‐off from bridging social capital—receiving support from the community—is what drives both objective and subjective resilience post‐Katrina. The results also show linking capital—support from institutions—can improve economic resilience. Our results provide evidence social capital is a key asset for long‐term resilience for small businesses. Business owners with links to the community and institutions—with more social capital—will be better off when facing a natural disaster.     

Sitting comfort and discomfort and the relationships with objective measures

The concepts of comfort and discomfort in sitting are under debate. There is no widely accepted definition, although it is beyond dispute that comfort and discomfort are feelings or emotions that are subjective in nature. Yet, beside several subjective methodologies, several objective methods (e.g. posture analysis, pressure measurements, electromyography (EMG) are in use to assess sitting comfort or discomfort. In the current paper a theoretical framework is presented, in which comfort and discomfort were defined and the hypothetical associations with underlying factors were indicated. Next, the literature was reviewed to determine the relationships between objective measures and subjective ratings of comfort and discomfort. Twenty-one studies were found in which simultaneous measures of an objective parameter and a subjective rating of comfort or discomfort were obtained. Pressure distribution appears to be the objective measure with the most clear association with the subjective ratings. For other variables, regarding spinal profile or muscle activity for instance, the reported associations are less clear and usually not statistically significant.     

Sitting comfort and discomfort and the relationships with objective measures

The concepts of comfort and discomfort in sitting are under debate. There is no widely accepted definition, although it is beyond dispute that comfort and discomfort are feelings or emotions that are subjective in nature. Yet, beside several subjective methodologies, several objective methods (e.g. posture analysis, pressure measurements, electromyography (EMG) are in use to assess sitting comfort or discomfort. In the current paper a theoretical framework is presented, in which comfort and discomfort were defined and the hypothetical associations with underlying factors were indicated. Next, the literature was reviewed to determine the relationships between objective measures and subjective ratings of comfort and discomfort. Twenty-one studies were found in which simultaneous measures of an objective parameter and a subjective rating of comfort or discomfort were obtained. Pressure distribution appears to be the objective measure with the most clear association with the subjective ratings. For other variables, regarding spinal profile or muscle activity for instance, the reported associations are less clear and usually not statistically significant.     

加权边沿自适应的场内插值去隔行方法*

为实现隔行扫描图像到逐行扫描图像的扫描格式转换,提出了一种基于空间加权和边沿自适应的场内插值去隔行算法。该算法包括LRV（left right vertical）评估和边沿自适应插值。相比传统的去隔行算法,LRV评估可以有效地消除伪边沿插值;在边沿自适应插值中增加预插值判断进行插值方向初步估计,可以抑制反向插值错误;在边沿方向搜索中增加空间权值,可以提高插值的准确率。实验结果表明,该算法在处理图片和视频流时的图像质量均要优于传统的算法。     

Road-safety education: spatial decentering and subjective or objective picture processing

The current study examined children's ability to analyse pictures of a risky situation, both in relation to the characteristics of the pictures and in relation to the centering/decentering process of cognitive development. Sixty children aged 6, 9 or 11 years were given an objective or subjective version of a story about a risky situation involving road crossing and were asked to reconstruct it by putting six pictures in chronological order. The type of picture series, objective or subjective, had a different effect on the children's understanding and performance, according to the age. The older children were better at ordering the pictures, but on the subjective version only. The picture-version effect on planning time decreased with age; only the younger children took more time to start touching the pictures. On one hand, it is concluded that for the youngest children, objective representations are essential to analysing pictures showing a risk, whereas the oldest children will profit more from a subjective view. On the other hand, subjective representations, which give a more realistic view, provide an excellent tool for testing children's abilities. Subjective representations can be used to detect potentially risky behaviour in virtual situations (static pictures, or multimedia tools), since it permits one to predict at-risk behaviour in the street and to assess the effectiveness of remedial measures.     

车辆开发过程中驾驶质量的客观评价及优化

针对整车驾驶质量开发中主观评价体系的不足,引入驾驶质量客观评价指标体系。明确驾驶质量开发的客观指标概念和目标曲线,以某款双离合变速器（dual cluth transmission, DCT)车型为研究对象,建立整车驾驶质量仿真模型,对爬坡度、加速度峰值、加速度增益进行分析,并通过优化车辆加速踏板扭矩策略和变速器换挡策略,使客观指标达到整车开发驾驶质量目标。整车驾驶性主观评价试验结果表明整车驾驶性满足开发目标要求,验证客观评价方法的可行性。