三基色激光显示中白平衡点的选择研究

为了探究激光显示技术中白平衡点的选择,基于颜色混合理论,采用立体色域算法研究了三基色激光显示中白平衡点改变对立体色域的影响.以D65立体色域为标准,结合色域覆盖率,得到了激光显示系统合适的白平衡点选择范围.结果表明,当白平衡点位于黑体轨迹上时,不同的波长组合下,白点色温的最佳选择都在6500K左右;进一步分析白点偏离黑...     

LCD视角的主观视觉感知评价方法

为了了解LCD显示器件的视角问题,设计了在LCD上显示静态图片的主观视觉评价实验.为了消除心理学中所谓的残留余象的影响,在此主观实验的基础上进行了一些改进和完善,引入了参考屏.并针对彩色图片在不同显示器重现上的颜色失真问题进行了相应处理.最后对两次的实验的数据结果进行了分析和比较, 改进后的实验对于LCD视角问题的研究更具有参考价值.     

准积分法构建视觉可感知三维色域的研究

为了更全面地评价显示器的色重显性能,用准积分法构建了人类视觉可感知三维色域.该算法用CIE标准色度观察者观察、混配等能单色辐射测得的CIE 1931 XYZ色度系统光谱三刺激值,按某一波长间隔求累加和,来近似实现未知函数表达式的多重积分运算.构建的色域囊括了人眼能识别的全部颜色,是宽色域、高动态范围显示设备的目标色域.还用三棱锥体积求和算法计算出该色域体积,验证了算法的可行性.进而由实测的LCD电视显示器数据,用同样方法计算其三维色域,并与视觉可感知三维色域进行定量比较.这些工作表明,本算法可为定量评价显示器的三维色域提供理论依据和可行算法,用这种方法给出的显示设备三维色域覆盖率可克服通常在二维色度图计算色域覆盖率的局限性.     

国际显示领域颜色标准的内容及架构分析

激光显示技术具有色域广、色饱和度高、节能环保等优点,被认为是最具有发展前景的显示技术之一。本文对YCC、sRGB、scRGB、xvYCC等国际与颜色管理相关的颜色标准进行了大量研究和分析,尤其对以上标准的适用范围,具有的优势及在现阶段大色域设备上适用局限进行了分析,希望借此对构建我国激光显示技术行业标准,为我国激光显示产业的发展奠定知识产权方面的基础。     

激光投影显示色彩管理系统

本文提出了一种适用于激光电视的新的颜色显示管理方法,该方法建立了激光三基色颜色显示与荧光粉三基色颜色显示之间的色度转换关系,不仅扩大了色彩显示的色域,而且实现两种色彩管理系统的相互兼容,该方法对于LED显示等宽色域显示系统的颜色管理,也有积极的借鉴意义。     

基于人眼视觉特性的三维显示技术

人眼是三维显示的第一接受器官,在深度视觉、空间/时间分辨、颜色/亮度响应等过程有其独特作用。针对三维显示中的立体图像质量、观看舒适度和临场感特性,对自由立体显示器中立体视疲劳、表面形变、大视场角显示质量和色带效应进行研究,从柱透镜的脉冲响应函数出发进行分析,并提出解决方法,在此基础上将多视点自由立体显示用于澄江古生物群科普宣传。同时讨论了集成成像中单元图像处理、立体深度和显示分辨率的问题,以及全息显示技术中的人眼视觉特性。     

宽色域液晶显示系统的研究

针对普通显示液晶系统在色彩表现方面的不足,在现有色域扩展技术的基础上,设计了一种以白和宝石蓝两种颜色发光二极管作为背光源的宽色域液晶显示系统。本文通过分析普通显示系统的色域,以色域覆盖率最大化为准则,选择主波长为501nm的宝石蓝发光二极管作为扩展背光源,扩展普通显示系统未能显示的青绿色区域。从理论上分析该系统的色域范围,并且详细介绍了系统背光源阵列、数据转发等功能模块的电路实现。实验结果表明:本文所设计的宽色域液晶显示系统的色域扩展了青绿色区域且色域覆盖率可达到45.65%。相比与其他多原色显示系统,本文设计的宽色域液晶显示系统不仅简化了硬件设计的复杂度,而且能够重现更多青绿色区域的颜色。     

基于视觉感知模型的彩色图像分割框架

图像分割是图像理解和识别的重要基础。目前,彩色图像分割有3个问题有待解决：无法处理有空间频率变化的图像;没有考虑图像的观察条件和颜色细节;对颜色空间的依赖性较大。本文提出了一个基于视觉感知的图像分割框架。此框架利用人眼视觉灵敏度函数模仿人眼的视觉模糊机制,能有效处理有空间频率变化的图像;使用CIECAM02来预测复杂观察条件下的图像色貌;最后应用不同的色差公式实现基于颜色相似性的分割算法。实验结果证明本文框架可以产生比传统算法更适合于人类感知的分割结果。     

基于视觉感知模型的彩色图像分割框架

图像分割是图像理解和识别的重要基础.目前,彩色图像分割有3个问题有待解决:无法处理有空间频率变化的图像;没有考虑图像的观察条件和颜色细节;对颜色空间的依赖性较大.本文提出了一个基于视觉感知的图像分割框架.此框架利用人眼视觉灵敏度函数模仿人眼的视觉模糊机制,能有效处理有空间频率变化的图像;使用CIE CAM02来预测复杂观察条件下的图像色貌;最后应用不同的色差公式实现基于颜色相似性的分割算法.实验结果证明本文框架可以产生比传统算法更适合于人类感知的分割结果.     

具有主观视觉补偿的人眼像差测量方法

为了准确测量人眼的各种低阶像差以及不规则的高阶像差,采用具有主观视觉补偿的人眼波前像差测量方法,进行了理论分析及实验验证,在客观测量的同时进行了主观视觉补偿,得出了测量的准确数据。结果表明,主观视觉补偿测量的波前像差小于客观测量的结果,被测者在观察视标时的适应性调整减小了波前像差,并且对于观察不同的视标时,波前像差的波动值较小。采用主观视觉补偿的测量方法,考虑实际观察目标时眼睛的状态,能够很好地对人眼像差进行补偿,得到符合实际状态的眼像差,这对制定人眼像差的治疗方案是非常有帮助的。     

一种基于人眼视觉特性的图像压缩方法

在讨论图像的二维变换的基础上,充分利用小波变换后各子带系数对重建图像的重要程度和人眼的视特性,引入了小波包的思想,并在随后的量化过程中,根据不同的频率带和不同的方向,给出不同的比特,然后由经验熵计算出相应的量化阈值。实验结果表明,该方法算法简单实用,压缩效果比较好。     

人眼海丁格尔刷效应的偏振感知建模与分析（特邀）

海丁格尔刷效应是一种人眼对线偏振光进行感知的内视效应,可用于判断人眼黄斑疾病的病变情况。针对现有海丁格尔刷效应图像存在难以精确仿真和分析的问题,通过三维琼斯矩阵和矢量对人眼的偏振感知效应进行计算,建立了一种人眼偏振感知模型,对理想、近/远视和散射等形式的人眼进行了偏振像差分析。结果表明:在人眼内介质均匀的情况下,人眼光瞳上正入射的460 nm波长线偏振光因晶状体[?5D,+5D]屈光度差异所产生的二向衰减小于1%。基于所建立的人眼偏振感知模型,利用入射偏振光的三维琼斯矢量对人眼光瞳上不同入射光场和屈光度的海丁格尔刷效应强度图像进行仿真计算,为海丁格尔刷效应的研究提供有效理论依据,扩大海丁格尔刷效应在人眼黄斑病变检测中的应用。     

Visual perception of Fourier rainbow holographic display

The rainbow hologram provides views of reconstruction with rainbow color within a large viewing zone. In our recent paper, a Fourier rainbow holographic display using diffraction grating and a white‐light LED source was introduced. In this technique, the rainbow effect is realized by the dispersion of white‐light source on diffraction grating, while the slit is implemented numerically by reducing the demands of the space‐bandwidth product of the display. This paper presents a novel analysis on the visual perception of the Fourier rainbow holographic display using Wigner distribution. The view‐dependent appearance of the image, including multispectral field of view and viewing zone, is investigated considering the observer and the display parameters. The resolution of the holographic view is also investigated. For this, a new quantitative assessment for image blur is introduced using Wigner distribution analysis. The analysis is supported with numerical simulations and experimentally captured optical reconstructions for the holograms of the computer model and real object generated with different slit size, reconstruction distance, and different observation conditions.     

不同年龄段健康儿童血清肌酸激酶同工酶(CK-MB)临床评估

目的比较不同年龄段健康儿童血清肌酸激酶同工酶(CK-MB)活性和质量差异,并对其临床合理应用进行探讨。方法选取184例健康儿童,按年龄阶段进行分组,同时选取30例健康成人设为对照组,分别采用酶免疫抑制法测定血清CK-MB活性,双抗体夹心法测定血清CK-MB质量。结果各健康儿童组和成人组CK-MB活性和质量呈明显正相关;儿童组CK-MB活性和质量随年龄增长呈下降趋势,趋近成人水平;各组质量检测均在正常参考范围,而低年龄儿童组CK-MB活性略高于临床正常值。结论临床医生在参考CK-MB活性和质量检测结果进行病情判断时,要考虑年龄因素;在临床诊断中CK-MB质量测定更优于活性测定。     

Assessing human perception

Network technology typically contains complex and nonlinear processes, such as low bit rate codecs for data reduction. This nonlinearity means that the perceived performance cannot be predicted with conventional engineering performance metrics. Reliable objective assessment of perceived performance is required for optimal design, commissioning and monitoring of quality. This paper looks at how BT can measure, optimise and control the perceived performance of the service that is provided. The final receiver of a signal is the human user — by modelling the senses of the human it is possible to predict whether an error would be perceptible. An auditory perceptual model has been developed and used to predict the subjective performance of a variety of nonlinear systems. Applications for the auditory model include design optimisation, as a measurement tool and as part of a nonlinear network planning tool. This paper focuses specifically on the auditory system, and how perceptual modelling is providing the basis for improved quality of voice service. However, as the global landscape adapts over the next decade, with multimedia, personal interactivity, and the concept of ‘virtuality’ then all of the human senses need to be considered together. Future work is planned to include an elementary visual model and the combination of sensory models for the assessment of multimedia products and services.     

Gazing-detection of human eyes based on SVM

A method for gazing-detection of human eyes using Support Vector Machine （SVM） based on statistic leaming theory （SLT） is proposed. According to the criteria of structural risk minimization of SVM,the errors between sample-data and model-data are minimized and the upper bound of predicting error of the model is also reduced. As a result,the generalization ability of the model is much improved. The simulation results show that, when limited training samples are used, the correct recognition rate of the tested samples can be as high as 100% ,which is much better than some previous results obtained by other methods. The higher processing speed enables the system to distinguish gazing or not-gazing in real-time.     

基于视觉感知的3D-HEVC帧间信息隐藏算法

由于传统的视频信息隐藏算法缺乏对人眼视觉感 知特性的研究,本文提出一种基于视觉感知 的3D-HEVC(3D High Efficiency Video Coding,3D-HEVC)帧间信息隐藏算法。首先,根 据立体显 著模型和大津阈值,将立体视频图像分为显著区域和非显著区域;然后,建立隐秘信息与量 化参数 QP(Quantization Parameter,QP)的映射关系,且针对不同的区 域,利用隐秘信息根据余数相等原 则相应的调制P帧或B帧的QP值;最后,用含隐秘信息的QP进行编码。实验结果表明,该 算法 平均每帧嵌入容量为246bit,相比于原始HTM13.0,所提算法编码重建立体视频序列的PSNR 值和SSIM值平均下降0.031dB和 0.000058,比特率仅平均增长0.0741%,且能对隐秘信息盲提取。     

Visual space-time geometry - A tool for perception and the imagination

Although the fundamental ideas underlying research efforts in the field of computer vision have not radically changed in the past two decades, there has been a transformation in the way work in this field is conducted. This is primarily due to the emergence of a number of tools, of both a practical and a theoretical nature. One such tool, celebrated throughout the nineties, is the geometry of visual space-time. It is known under a variety of headings, such as multiple view geometry, structure from motion, and model building. It is a mathematical theory relating multiple views (images) of a scene taken at different viewpoints to three-dimensional models of the (possibly dynamic) scene. This mathematical theory gave rise to algorithms that take as input images (or video) and provide as output a model of the scene. Such algorithms are one of the biggest successes of the field and they have many applications in other disciplines, such as graphics (image-based rendering, motion capture) and robotics (navigation). One of the difficulties, however is that the current tools cannot yet be fully automated, and they do not provide very accurate results. More research is required for automation and high precision. During the past few years we have investigated a number of basic questions underlying the structure from motion problem. Our investigations resulted in a small number of principles that characterize the problem. These principles, which give rise to automatic procedures and point to new avenues for studying the next level of the structure from motion problem, are the subject of this paper.     

Visual perception of computer-generated stereoscopic pictures: Toward the impact of image resolution

In comparison with the generation of monoscopic images, the time cost of rendering stereoscopic images is doubled. When generating stereoscopic images by computer algorithms, it is desirable to save the computational expense by decreasing the image resolution, without degrading the visual perceptual quality of the images. In this work, to evaluate the perceptual visual quality of computer-generated stereoscopic images (CGSIs), a data set consisting of stereoscopic images created with different horizontal and vertical resolutions was constructed. First, a series of subjective experiments for the analysis of various perceptual situations was conducted. The experimental results show that when the original image resolution was reduced by half, the image difference was not perceptible. In addition, based on full-reference (FR) and no-reference (NR) image quality measurement (IQM), a combined FR-and-NR CGSIQA model was established to predict perceptual quality. We perform weighting calculations for different combinations of FR and NR. The experimental results show that the proposed model significantly outperforms all the classical models.     

Signal compression based on models of human perception

The notion of perceptual coding, which is based on the concept of distortion masking by the signal being compressed, is developed. Progress in this field as a result of advances in classical coding theory, modeling of human perception, and digital signal processing, is described. It is proposed that fundamental limits in the science can be expressed by the semiquantitative concepts of perceptual entropy and the perceptual distortion-rate function, and current compression technology is examined in that framework. Problems and future research directions are summarized