液晶显示器颜色特征化的S模型算法

基于对液晶显示器的呈色机理的分析,提出了一种新颖的S-shape模型,并用其代替GOG(增益-偏置-伽马)模型来实现液晶显示器阶调复现曲线的精确拟合及液晶显示器颜色特征化精度的提高。为了检验改进算法的精度,分别用GOG模型和S模型来建立同一台液晶显示器的颜色空间变换,作为LCD颜色特征化的参照,GOG模型被用于来建立阴极射线管显示器的颜色特征化模型,并在设备的相关颜色空间,通过均匀取样选取7×7×7组颜色数据来检验这3种颜色空间映射实例的精度。实验结果表明,对于液晶显示器而言,基于S模型的颜色映射精度比GOG模型有明显提高,其平均色差/最大色差分别为1.825/4.731个CIEDE2000色差单位,与GOG模型应用于阴极射线管显示器的颜色特征化的精度相当。     

基于sRGB颜色空间的CRT显示色差分析

为了实现颜色信息的标准化显示和交流,一般需要标定或规定特定CRT显示器的RGB空间与标准的CIEXYZ空间的变换关系.目前的sRGB标准可以看作一种缺省的独立于设备的颜色变换空间,由于它依据大多数CRT的颜色显示特性建立,因此能精确描述颜色以及为CRT提供基本颜色空间,使CRT显示器以快捷的方式得到较好的显示图象.为使sRGB标准能用于CRT标准化颜色显示,在归纳分析sRGB标准的数学模型的基础上,结合对具体实验数据的分析,给出了sRGB标准用于CRT标准化颜色显示的色差范围,并探讨了sRGB标准用于CRT标准化颜色显示的可行性.     

彩色CCD摄象机的光强—灰度响应线性化及其在颜色定标中的应用

现今的工业彩色摄象机主要用作图象显示器的输入设备,其性能标准是通过人的视觉感知的图象的质量.并不完全适合于计算机视觉系统中传感器测量物体表面颜色特性的要求.为此要对工业彩色摄象机的特性进行测定和校准.本文提出一种恢复彩色 CCD 摄象机光强——灰度响应线性关系(即光谱线性化)的方法.实验表明。此方法可以消除或减轻光强的变化对色度坐标的影响.变换后的图象仅比原图象有少许变暗.最后说明该方法在颜色定标中的应用——可提高使用彩色 CCD 摄象机进行颜色标定的精确度.     

基于DSP平台的图形显示的研究与应用

为了探索虚拟平台技术在引导设备中应用的可行性,对DSP图形处理技术结合传感器信号实施虚拟水平指示图形的显示控制进行了研究.构建了DAM6416P为核心的开发平台,在该平台中,通过试验比较了直线生成算法的画线速度.研究了RGB颜色空间以及YUV颜色空间,通过实验得出不同数据格式在等离子显示器上的几种颜色数值.采集倾角传感器的输出信号,使用C语言编制了指示图形,实时输出到双等离子显示器上,指示舰船的横摇状态.     

彩色图像工程中常用颜色空间及其转换

颜色空间是彩色图像工程面对的首要问题.为了对颜色进行量化的、确定性的管理以及综合性的应用,时彩色图像工程中经常用到的颜色空间进行了分类和系统地阐述,并从工程应用的角度重点介绍了这些颜色空间的应用背景及其之间转换.为研究设备彩色特性,进行色彩管理和处理彩色图像打下了基础.     

彩色数字仪表图像二值化技术研究

针对石英晶体振荡器的计量检定中对数字仪表高精度识别的要求,通过对各种灰度及彩色图像二值化技术及HVS颜色空间特性的研究,提出一种在HVS颜色空间下进行彩色图像二值化分割技术,讨论了HSV颜色空间中H、S、V三分量对彩色图像二值化的影响及意义,分析并给出了H、S、V三阂值的计算方法,在实际使用中取得了满意的效果。采用该技术并结合校验神经网络,实现了数字仪表面板数字的高精度识别,达到了石英晶体振荡器的计量检定误识率低于0．001的项目要求。     

基于两种色彩空间的颜色选择方法

本文分析和比较了HSI和RGB两种色彩空间的特性，提出了一种基于两种色彩空间，可以实现人机交互的选择颜色的方法，并设计了基于该方法的颜色编辑器，通过对彩色图像处理的实验，结果证明该方法适用而且有效。     

彩色数字仪表图像二值化技术研究

针对石英晶体振荡器的计量检定中对数字仪表高精度识别的要求,通过对各种灰度及彩色图像二值化技术及HVS颜色空间特性的研究,提出一种在HVS颜色空间下进行彩色图像二值化分割技术,讨论了HSV颜色空间中H、S、V三分量对彩色图像二值化的影响及意义,分析并给出了H、S、V三阈值的计算方法,在实际使用中取得了满意的效果.采用该技术并结合校验神经网络,实现了数字仪表面板数字的高精度识别,达到了石英晶体振荡器的计量检定误识率低于0.001的项目要求.     

综合颜色和局部空间特征的彩色图像检索方法

针对图像颜色空间的分布特性,提出一种用颜色色调直方图来表达图像的颜色特征;通过HSV颜色空间的三个独立分量表示方法来描述颜色的空间特征,具有旋转、平移、尺度不变特性。实验表明,该方法很好地克服了颜色直方图和颜色矩无法表达图像色彩的空间位置的缺点,显示了组合特征的图像检索特征的有效性和较高的检索准确性。     

彩色图像显示系统的色彩还原技术研究

图像从输入设备到显示器观察,再到输出设备或最终的图像文件的流程中,由于不同设备的呈色机理、呈色特性、所采用的呈色空间不同,造成颜色信息在不同的设备间传递时出现了偏差,要维护原始的色彩是非常困难的。借助PCS空间,通过多项式分区回归的方法进行色彩空间转换。实验结果表明,这种方法能够实现彩色图像显示系统的色彩还原且精度较高。     

Generalized mixed-mode reflective LCDs with large cell gaps and high contrast ratios

Abstract— A generalized mixed twisted-nematic/birefringent-effect mode reflective LCD is presented. This new mode encompasses all previously published reflective nematic LCD modes and is clearly shown on the parameter space diagrams. We also discuss how to obtain operating conditions of this generalized mixed-mode display with large cell gaps, low color dispersion, and high contrast at low voltages. This operating mode is particularly suitable for reflective crystalline-silicon-backplane active-matrix LCDs.     

Evaluating and improving color washout of vertical aligned liquid crystal display

We demonstrated an optimized 8-domain vertical aligned (VA) liquid crystal display (LCD) by minimizing its color washout. The index G is adopted to analyze the degree of color washout through simulation. By using linearly and circularly polarized incident light, the optimized regime of the area and applied voltage ratios of sub-pixels is obtained. In the experiments with the circularly polarized light, the images are sensuously improved in a coupled capacity type LCD by applying the simulated applied voltage ratio of two sub-pixels.     

Masking model for accurate colorimetric characterization of LCD

Abstract— A color management system (CMS) such as ICC profile or sRGB space have been proposed for color transformation and reproduction of cross media. In such a CMS, accurate colorimetric characterization of a display device plays a critical role in achieving device‐independent color reproduction. In the case of a CRT, colorimetric characterization based on a GOG model is accurate enough for this purpose. However, there is no effective counterpart in liquid‐crystal displays (LCDs) since the characterization of an LCD has many difficulties, such as channel interaction and non‐constancy of channel chromaticity. In this paper, a new method of display characterization is proposed which is applicable to the assessment of color reproduction of LCDs. The proposed method characterizes an electro‐optical transfer function considering both channel interaction and non‐constancy of channel chromaticity. Experimental results show that the proposed method is very effective in the colorimetry of LCDs.     

Paradigm for achieving color‐reproduction accuracy in LCDs for medical imaging

Abstract— A methodology and associated software modules for calibration, characterization, and profiling of color LCDs for color‐critical applications in medical imaging is described. Supporting analyses reveal very high color‐reproduction accuracy as determined by CIE DE2000 color differences for 21 0 test colors uniformly distributed in CIE Lab color space. The impact of the LCD tone‐reproduction curve on color‐reproduction accuracy is compared for two tone‐reproduction curves of special interest in medical imaging: the DICOM gray‐scale standard display function and the CIE L* standard lightness function. The initial results from a psychophysical investigation of the diagnostic performance of trained pathologists viewing “virtual” breast biopsy slides are reported and the diagnostic performance achieved with calibrated, color‐managed LCDs with uncalibrated LCDs without the benefits of color management is compared.     

A geometrical approach for inverting display color‐characterization models

Abstract— Some display color‐characterization models are not easily inverted. This work proposes ways to build geometrical inverse models given any forward color‐characterization model. The main contribution is to propose and analyze several methods to optimize the 3‐D geometrical structure of an inverse color‐characterization model directly based on the forward model. Both the amount of data and their distribution in color space is especially focused on. Several optimization criteria, related either to an evaluation data set or to the geometrical structure itself, are considered. A practical case with several display devices, combining the different methods proposed in the article, are considered and analyzed.     

The Spectral Radiance Piecewise Partition Model for characterizing Liquid Crystal Displays

The Spectral Radiance Piecewise Partition Model (SRPPM) is a new model for characterizing Liquid Crystal Displays (LCD). According to the additive property of the spectral radiances of the primary displayed color, the SRPPM model can be divided into three subspace partitions to calculate the transfer coefficient matrixes with cubic polynomial, which based on the relationship between the digital input of the LCD and the spectral radiance of displayed color. The color difference was used to evaluate the accuracy of this model. Comparing with other characterization models for LCD, the experimental results show that the average color difference of SRPPM is 0.82ΔE₇₆, and 80% of the color differences between color samples are less than 1ΔE₇₆.     

CRT and LCD monitor and process materials evaluated for environmental improvement

Decision rules have been developed and applied to the bills of materials of a color cathode‐ray tube (CRT) and a liquid‐crystal‐display (LCD) desktop monitor to determine which product and process materials will be evaluated in an environmental life‐cycle assessment. Materials of significant mass, of technological importance, and of potential environmental impact are targeted. The list of materials identified are those for which life‐cycle inventory data will be obtained for the materials extraction and materials processing life‐cycle stages of a CRT and an LCD. Additionally, materials identified will also be used to represent life‐cycle impact in terms of resource consumption, as well as surrogates for occupational health impacts.     

Flexible active‐matrix OLED displays: Challenges and progress

Abstract— Organic light‐emitting‐device (OLED) devices are very promising candidates for flexible‐display applications because of their organic thin‐film configuration and excellent optical and video performance. Recent progress of flexible‐OLED technologies for high‐performance full‐color active‐matrix OLED (AMOLED) displays will be presented and future challenges will be discussed. Specific focus is placed on technology components, including high‐efficiency phosphorescent OLED technology, substrates and backplanes for flexible displays, transparent compound cathode technology, conformal packaging, and the flexibility testing of these devices. Finally, the latest prototype in collaboration with LG. Phillips LCD, a flexible 4‐in. QVGA full‐color AMOLED built on amorphous‐silicon backplane, will be described.     

Ultrawide color gamut LCD display with CdSe/CdS nanoplatelets

We present a liquid‐crystal display (LCD) backlight made of nanoplatelets (NPLs) for the first time. Owing to the narrow emission linewidth of NPLs (8‐12 nm) and quantum dots (QDs), the spectrum exhibits a wide color gamut display with a 139.9% color gamut of National Television System Committee (NTSC) 1953 standard and 104.5% Rec.2020 (ITU‐R Recommendation BT.2020), realizing a truly ultrawide color gamut LCD display.     

Color performance of an MVA‐LCD using an LED backlight

Abstract— The color performance, including color gamut, color shift, and gamma curve, of a multi‐domain vertical‐alignment (MVA) liquid‐crystal display (LCD) using an LED backlight are calculated quantitatively. Simulation results indicate that an LED backlight exhibits better angular color uniformity and smaller color shifts than a CCFL backlight. Color gamut can be further widened and color shift reduced when using a color‐sequential RGB‐LED backlight without color filters, while the angular‐dependent gamma curves are less influenced using different backlights. The obtained quantitative results are useful for optimizing the color performance and color management of high‐end LCD monitors and LCD TVs.