基于多元回归方法的激光显示颜色校正

应用计算机系统处理多元回归方法,是当今处理非线性关系的常用方法,本文阐述了激光显示中,由于三基色与传统显示三基色的选取不同,造成在现有电视制式下激光显示的颜色偏差。由于系统误差和其他影响,很难找到现有CRT制式和激光显示可以实际应用的关系式。我们通过多元回归的方法建立了激光显示色域与现有CRT?显示色域之间的关系。同时我们提出的多元回归方法,对在诸如液晶显示、大屏幕LED显示等需要颜色矫正的领域,有积极的借鉴意义。     

激光显示中的色度学研究

以国内普遍采用的PAL电视制式为例,建立了以目前所选用的红(671nm)、绿(532nm)、蓝(473nm)三色激光为三基色的颜色系统模型与电视三基色系统的转换关系.解决了所用三色激光器的功率匹配问题.并通过颜色虚拟的扩展,将PAL电视制式中无法显示的颜色扩展到激光色域内,使再现色彩更丰富,颜色更饱和.为下一步在PAL制式下电路实现激光显示色域校正建立了理论基础.该方法亦可推广到其它制式下,同时对如液晶显示、LED显示等需要颜色矫正的领域,也有积极的借鉴意义.     

基于TMS320C6416的色域扩展方法

由于激光电视覆盖的颜色区域是传统电视的颜色区域1.98倍,所以在激光电视等领域中需要一种转换系统快速完成荧光色域到激光色域的颜色扩展。本文给出了三组不同波长激光的色域扩展矩阵,在基于TMS320C6416的图像处理平台上实现了色域的转换,并且利用多种加速算法,加快了处理速度。实验结果表明,本文的方法有效地扩展了激光电视的颜色区域,降低了图像的饱和度。     

地图色彩计算机辅助设计（MCCAD）研究

ＭＣＣＡＤ研究包括印刷色标的制定、屏幕再现与印刷复原的模型转换研究、专家设色系统等。本文在色度学理论基础上，通过实验方法，对ＣＭＹ印刷颜色系统和ＲＧＢ屏幕颜色系统的色度数据、色域范围进行了系统分析，导出了一个比现有ＣＲＴ、ＰＡＬ和ＮＴＳＣ颜色模型使用范围广、色域转换范围大的新模型。解决了地图印刷色标屏幕再现的关键技术，建立了地图色谱数据库，举例介绍了彩色地图的ＣＡＤ方法。为地图色彩ＣＡＤ、印刷工艺数据化、标准化设计提供了技术手段。     

基于灰色变权搜索的软件故障预测方法

针对软件故障数目历史数据的小样本特征,在传统灰色模型基础上,将预测模型的建模问题转换为灰色权因子的搜索问题,建立了变权搜索模型进行故障数目预测;提出用实测和预测序列的均方误差和斜率距离构建搜索指标集,用欧式距离构建计算各指标权重的最优准则函数,对模型的灰色权因子进行全局最优搜索,权因子随故障发展过程实时变化;经实例仿真,预测与实测序列相对误差较小,验证了所提方法的可行性和有效性,对装备软件风险评估提供了有效的决策支持。     

基于粒子群优化的支持向量机在瓦斯浓度预测中的应用研究

为了准确预测煤矿瓦斯浓度,基于从芦岭煤矿KJ98监控系统中提取的生产现场瓦斯浓度时间序列数据,对基于粒子群优化的支持向量机理论在瓦斯浓度短期预测中的应用进行了研究。首先对瓦斯浓度时间序列进行小波软阈值去噪和相空间重构等预处理,然后采用粒子群优化算法对支持向量机的惩罚因子、损失函数、核函数参数进行了优化,并基于最优参数建立了瓦斯浓度预测的支持向量机模型。仿真结果表明,采用粒子群优化的支持向量机理论进行煤矿瓦斯浓度预测,极大地提高了预测的准确性和精确度;误差分析结果表明,该方法预测结果的误差很小,且测试样本越小,误差越小。     

基于非线性误差补偿的蓝藻水华时序综合预测方法

针对现有蓝藻水华预测方法中大多仅采用智能模型或时序模型无法准确描述水华生成过程、预测精度不高等问题,本文根据蓝藻水华生成过程中同时存在的非平稳及非线性变化特点,在水华多元非平稳时序模型预测基础上,采用多种智能非线性模型对其非线性预测误差进行预测及补偿,从而提出将多元非平稳时序模型与智能模型相结合的蓝藻水华综合预测方法。本方法首先对蓝藻水华采用多元非平稳时序模型预测并提取非线性预测误差,通过核主成分分析法对影响预测误差的各因素进行分析,利用适于非线性系统建模的遗传算法(GA)优化最小二乘支持向量机(LSSVM)模型及BP神经网络模型对时序模型的非线性预测误差进行预测并补偿,从而提高水华预测精度。本文针对同一批蓝藻水华数据分别采用多元非平稳时序、BP、LSSVM、GA-BP、GA-LSSVM五种方法进行对比分析,实验结果表明,所提出的误差预测模型得到的蓝藻水华预测结果相比仅采用多元非平稳时序方法更符合实际,同时,GA-BP及GA-LSSVM模型的非线性误差预测结果相比BP及LSSVM精度更高,而在小样本情况下,GA-LSSVM模型的预测结果相比GA-BP模型精度更高,稳定性更好。因此本方法解决了现有的蓝藻水华预测精度不高、单一模型建模容易丢失信息等问题,提高了蓝藻水华建模预测的效果。     

SVR算法在商机管理中的应用

随着市场竞争日益激烈和信息化技术不断发展,通过数据分析和挖掘来预测新的潜在商机成为了企业商机管理的重要环节。现有机器学习算法主要基于样本数目趋于无限大的假设,但实际问题中样本大多是有限的,甚至是小样本数据,难以保证机器学习结果的合理性。将支持向量回归(SVR)算法用于商机预测建模过程,用于解决小样本、高维数、非线性的学习问题。实验结果表明,与决策树等算法构造的目标函数求解结果相比较,SVR算法在有限样本空间能获得较高精度的预测结果。     

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。     

一种基于颜色空间最短距离的编码误差修正新方法

在视频编码的过程中, 编码后的数据不可避免地会发生一定程度的失真。在这些失真的色点中会有一部分的色点跃出颜色空间的范围, 因此在视频编码框架的重建部分使用了误差修正(clip)来修正这些误差点。现有的误差修正方法仅仅是对YUV数据中各个分量进行了简单的超出0~255范围的修正, 而忽略了颜色空间变换后YUV的颜色空间模型的变化。针对该问题, 提出了一种基于颜色空间最短距离的编码误差修正（minimum distance clip）新方法。该方法利用YUV颜色空间模型以及空间几何的理论, 通过寻找这些误差点在该模型上的最短距离点来修正上述误差。采用H. 264参考软件JM13. 0进行实验验证, 测试结果表明, 该方法较传统的修正方法在主观质量和客观性能上均有一定的提高, 对有较高色彩质量需求的先进视频编码应用, 如超高清视频、3DTV等有一定的贡献。     

A method for selecting display primaries to match a target color gamut

Abstract— A method for selecting primaries of a wide‐gamut display is proposed, in which display color gamut is designed to match a target color gamut in CIELAB color space. A standard deviation of the relative maximum chroma of display and target color gamuts is defined. The selection method optimizes display primaries for the minimum standard deviation so that display and target color gamuts are similar in shape. It is shown that the color gamut of a laser display designed by this method is similar in shape to the theoretical maximum, or optimal, color gamut of objects. It is also shown that the color gamut of an LED display can be designed to include 99.7% of the gamut of Pointer's real‐world surface colors. LED primaries are selected to minimize the standard deviation of the relative maximum chroma of effective display color gamut and a target color gamut which is defined to include Pointer's real‐world surface colors. For both the laser and LED displays, it is necessary to constrain the red‐primary wavelength to avoid excessive optical power for the red primary.     

Optically adjustable display color gamut in time-sequential displays using LED/Laser light sources

Recently, various wide color gamut displays have been developed. Because of color gamut differences between wide gamut displays and the standard definitions, the color reproduction on such display system is not equal to original images. To overcome this, a color transformation such as gamut mapping algorithm is applied in conventional systems. But this manipulates only the video signal that would reduce the signal dynamic range and produces quantization error of video signal.In this paper, we propose a new optical Color Gamut Processing instead of an image data mapping. In the method, an individual color gamut of the standard definitions can be composed of an optical mixture of original primary colors. As a result, a perfect color match for the various standards can be realized within a display gamut without any signal artifacts.Moreover the same concept is applied to the video stream in order to elevate scene luminance. A scene-adaptive Dynamic Color Gamut Processing measures a color gamut for every video frame and adjusts a matched display color gamut so that it is able to increase display contrast in comparison to conventional display systems.     

Hybrid spatial‐temporal color synthesis and its applications

Abstract— A novel approach of synthesizing display color by hybrid color processing in both the spatial and temporal domains is introduced. The rational basis for this approach is found in vision science, and more particularly in the spatial and temporal characteristics of the human visual system. Various examples of the new approach, aiming at different display‐performance objectives, are described. Hybrid spatial‐temporal color synthesis can be used to generate a three‐primary RGB display, the analysis of which reveals a higher spatial resolution and a lower fixed‐pattern noise. The concept has also been used to build, based on a conventional LCD panel in combination with an adapted backlight system, a six‐primary LCD TV with a 22% wider color gamut. Finally, the approach is demonstrated in a four‐primary mobile LCD and results in lower cost combined with a higher display luminance and a wider color gamut.     

Achieving standard wide color gamut by tuning LED backlight and color filter spectrum in LCD

In order to achieve the standard red, green, and blue (sRGB) standard color gamut in color liquid crystal display and improve the image quality, the impact of the backlight and color filter spectrum on module's chroma was simulated and analyzed. The color gamut was enhanced by adjusting and optimizing the two parts of spectrums of LED backlight and color filter and by using red and green phosphor LED backlight to match the new color filter with an appropriate thickness. Experimental results show that: When the thickness of color filter is 2.2 µm, National Television System Committee color gamut increases from 65.3% to 74.9%, and sRGB matching rate enhances from 83.2% to 100%, achieving a full coverage of the sRGB standard color gamut, the transmittance of white light reaches 28.1%. Also, it is verified that shifting the peak position of the backlight and color filter spectrum to purification direction, as well as narrowing its half‐width can upgrade the color gamut. Meanwhile, the thicker the thickness of color filter is, the wider color gamut it has, based on the same pigment material.     

Power‐saving primary design for displays enclosing a target color gamut

Abstract— Display primaries are optimized for the trade‐off between the total primary power and color gamut under the requirement that a target color gamut is enclosed by the color gamut of the display. LED displays and HDTV color gamut are taken as examples. Compared to the display using a set of typical commercial RGB LEDs, it was found that a total optical (electrical) power of 23.6% (15.6%) can be saved for the display using optimal RGB LEDs. Although the size of the display color gamut is sacrificed, the color gamut of the display using optimal RGB LEDs still encloses the HDTV color gamut. The combined effect of the LED luminous efficiency and white‐point condition on the determination of the optimal LED wavelengths and bandwidths is also studied.     

Measuring the color capability of modern display systems

Historically displays used three colorants in an additive system. During that time, the CIE chromaticity diagram adequately illustrated color capability. Modern displays are not constrained by this additive architecture, and the diagram can fail in its purpose. This is demonstrated by analysis and a large number of display measurements. A device‐independent methodology using CIE 1976 L*a*b* color gamut volume is described that provides a robust means to determine the size of the color gamut. This methodology is then extended to the ‘gamut rings’ diagram as a solution for visualizing color capability that directly correlates to color gamut volume. It is further shown how the methodology can be applied to determine the intersection between two gamut volume boundaries.     

Seventeen‐inch laser backlight in‐plane switching liquid crystal display with 8K, 120‐Hz driving,and BT.2020 color gamut

We have developed a 17‐inch laser backlight in‐plane switching liquid crystal display satisfying the main BT.2020 specifications, which are 8K, 120‐Hz driving, and a BT.2020 wide color gamut. The color gamut of the developed in‐plane switching liquid crystal display covers 98% of the BT.2020 wide color gamut, thanks to a laser backlight and appropriate color filters. The liquid crystal response time of 5 ms, which is sufficient for 120‐Hz driving, is achieved by adapting a faster in‐plane switching liquid crystal display, namely, the short‐range lurch control in‐plane switching liquid crystal display.     

Analysis of color volume of multi‐chromatic displays using gamut rings

There are claims that multi‐chromatic displays can achieve a wider color gamut by the use of additional highly saturated secondary color channels. However, there are other claims that these displays lose lightness and/or color saturation at brighter levels. These apparently divergent views have led to some controversy in the display industry and at standard setting organizations. This study examines the color gamut volume for a variety of simulated and measured multi‐chromatic (sometimes incorrectly referred to as “multi‐primary”) displays using combinations of white and/or secondary color channels, such as cyan, magenta, and yellow. Furthermore, a two‐dimensional gamut representation, referred to as “gamut rings,” is introduced to illustrate that the addition of nonprimary optical color channels to a trichromatic (RGB) display can result in a significant decrease in the chroma at higher lightness levels. The additional saturated color channels can increase the gamut volume only around their hues at darker levels. The results also confirm the validity of comparing the color light output and white light output for revealing the design trade‐offs between the high‐peak white and the color‐image brightness for multi‐chromatic displays.     

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.     

Spatially uniform colors for projectors and tiled displays

Abstract— A major issue when setting up multi‐projector tiled displays is the spatial non‐uniformity of the color throughout the display's area. Indeed, the chromatic properties do not only vary between two different projectors, but also between different spatial locations inside the displaying area of one single projector. A new method for calibrating the colors of a tiled display is presented. An iterative algorithm to construct a correction table which makes the luminance uniform over the projected area of one single projector is presented first. This so‐called intra‐projector calibration uses a standard camera as a luminance measuring device and can be processed in parallel for all projectors. Once the color inside each projector is spatially uniform, the set of displayable colors — the color gamut — of each projector is measured. On the basis of these measurements, the goal of the inter‐projector calibration is to find an optimal gamut shared by all the projectors. Finding the optimal color gamut displayable by n projectors in time O(n) is shown, and the color conversion from one specific color gamut to the common global gamut is derived. The method of testing it on a tiled display consisting of 48 projectors with large chrominance shifts was experimentally validated.