基于CIECAM02色貌模型的数码相机色彩管理

为改进数码相机应用ICC色彩管理只考虑光源对呈色影响的缺陷,将色貌模型引入了数码相机色彩管理。在ICC色彩管理的基础上,用VC++开发了"从色度值到色貌值"的转换模型,以拍摄色貌值与显示色貌值颜色属性(色貌)一致为目标,利用软件生成并编辑了特性文件,应用色貌色差公式作为评价特性文件的标准,确定了3种典型光源(D65,D50,A)环境下,数码相机的特性文件,达到了人眼视觉上色彩的准确复制。     

基于数码相机色彩管理的研究

数码相机已经成为图像输入的主要设备,为数码相机提供Profile,是以数码相机作为图像输入设备的色彩管理的关键步骤之一.从数码相机色彩管理的必要性出发,介绍了色彩管理,并对建立数码相机的Profile文件并用该文件对同条件下拍摄的图像进行色彩管理的方法作了详细的介绍.     

数码摄影师的色彩管理讲座(5)色彩管理系统(CMS)和色彩配制文件(ICC Profile)

色彩管理的基本原理 ①以标准化方式来定义与控制拍摄（数码相机）、输入（扫描仪）、显示（显示器、投影仪）、输出（打印机、印刷机）等设备的色彩表现（描述）特性,例如色域等,并将此设备的色彩表现特性形成完整的色彩配制文件,通常用“ICC Profile”或“ICC色彩配制文件”表示。     

数码摄影师的色彩管理讲座（10）——图像扫描仪的色彩管理

数码相机通常采用外部照明光进行拍摄工作,光源可能是直射的太阳光,或是多云或阴天的日光,还有室内的各种人造灯光,有时还使用外接闪光灯等.这些照明光的色温和强度是千变万化的,同时还经常存在多种光源混杂在一起照射被摄景物的现象.但是,数码相机的色彩管理只能在指定的光照条件下完成,例如在光照基本稳定不变的影室内进行,使创建的ICC Profile色彩配制文件适用范围受到限制.为此,建议为日光和白炽灯照明条件下的数码相机分别创建ICC Profile色彩配制文件.     

显示器色彩管理的研究与实践

分析了显示器色彩管理对计算机软硬件性能的要求,提出了满足显示器色彩管理性能要求的计算机软硬件配置标准;通过分析环境色和光源对屏幕色彩造成的影响, 确定显示器色彩管理的环境要求;通过论述显示器校正、准确测量的方法、计算机操作系统对显示器特征文件的正确调用、Photoshop软件色彩管理的完整设定,实现显示器的色彩管理,达到不同显示器对同一图像显示一致,使整个生产过程中颜色一致.     

色彩管理中灰平衡数据控制

目的针对Photoshop色彩管理中数码样张与印刷样张存在较大的色差问题,提出了修正ICC Profile文件的方法。方法以灰色为研究对象,利用数码打样机分别输出了GMG和Photoshop色彩管理流程下的数码样张,分析比较了2种流程下数码样张的色差特性,并利用ProfileEditor软件对印刷ICC Profile文件进行灰平衡数据的调整与修正。结果在Photoshop色彩管理流程中使用调整后的ICC Profile文件,使仿铜版纸的数码样张中性灰的平均色差由原来的8.0863降低到4.2284,仿特种纸的数码样张中性灰的平均色差由原来的10.1063降低到5.5908。结论优化ICC Profile文件中的灰平衡参数,能够使数码样张与印刷样张获得更小的色差,提高了颜色再现的准确性。     

论色彩与小区景观的营造

自然界因为色彩的点缀而显得生机勃勃。世间万物因为自身独特的颜色而显出个性的魅力。在景观设计中利用色彩的组合构成，改变传统的构图方式，可以使环境更加丰富多彩和更具有魅力特性。本文就色彩在景观设计中的应用进行初步探讨。     

色彩管理之CRT显色特征的探讨

通过测试显示器的颜色,了解CRT的显色特征,建立特征函数模型,并对函数模型进行误差验证,提供色彩管理的特征文件.为色彩管理提供了思路.     

儿童家具色彩设计技术

设计案例总结了儿童家具常用色彩,分析了颜色设计和型元素相互影响的具体过程,对不同色彩设计的型语言处理做了具体说明。     

基于色彩管理的彩色CRT特征函数的研究

通过测试显示器的颜色,了解CRT的显色特征,建立特征函数模型,并对函数模型进行误差验证,提供色彩管理的特征文件,为建立开放环境下的彩色显示器的色彩管理系统打好基础、作好准备.     

基于ICC色彩管理的1-bit TIFF在数码打样中的应用

以胶印印刷样张为仿真打样对象,建立标准ICC Profile文件,推导了印刷系统与数码打样系统之间的色域映射关系,并反馈到数码打样系统中进行修正,重新进行色域匹配和二次验证,确保了印刷样张与数码样张的一致性。结果表明,通过选择性校色对打样ICC Profile特征文件进行编辑校正,能将色差降低到打样的要求,且RIP后打样能模拟出龟纹、补露白等,提高了印刷追样的可行性。     

数码打样色彩管理系统的研究

数码打样在印刷工业的色彩管理中起着重要的作用.文中介绍了数码打样系统与色彩管理系统的基本内容,并对数码打样色彩管理系统的合理选择及存在的问题进行了讨论分析.研究表明,重视并运用好色彩管理软件和专用的ICC制作软件包,是目前提高数码打样中色彩匹配能力的有效方法.     

以色度转换实现承印材料底色的校正的方法研究

利用Kodak的Approval打样系统测试了13种印刷常用纸张,总结了纸张底色对印刷色彩的影响,并比较了校正纸张底色的3种色度转换方法:不同测量衬垫的色度转换方法、相对色度转换方法和基于测量数据的多项式转换方法。分析比较发现:如果印刷中使用理想黑,则不同测量衬垫的色度转换方法与相对色度转换方法是等效的;印刷色彩由于纸张底色差异所引起的色彩偏差,并非完全符合线性的转换关系,因此基于测量数据的多项式的色度转换方法的转换结果更加准确,特别是当2种纸张间底色的色差大于4ΔEa*b*时;由于多项式的转换需要使用所有复制色彩的测量数据,造成了实际应用中的诸多不便,因此ISO 13655标准中的不同测量衬垫的色度转换方法较适用于纸张底色偏差的校正。     

数码相机颜色复制性能的研究

实验选取了 2 款具有代表性的数码相机,采集了各设备在制作特性化文件前后的特性化数据,接着通过数据拟合和进一步分析,得出了数码相机之间的性能差异,最后通过建立六大评判标准进行主观评价,对实验结果进行验证。 实验结果表明,进行色彩管理图像的色差要小于未进行色彩管理图像的色差,由制作特性化文件前后图像效果的差别,可知制作数码相机的特性文件是很有必要的。 最后给出了不同相机不同拍摄条件下对不同原稿的再现结果,为相关工作者和使用者提出一项可行的评价方案。     

Red-and-green-based pseudo-RGB color models for the comparison of digital images acquired under different brightness levels

Digital images of crops and other plants are useful in plant management although the brightness of digital images varies with time. Brightness adjustment of the entire area of color digital images has been quite difficult due to the absence of correlations among color components and brightness. Redness and greenness best correlate with brightness. Hence, red- and green-based pseudo-color models could enable the adjustment of brightness of the entire area of color digital images. A pseudo-color model, a red–green–white mat model, lost most of the information on yellowness when tested with a color gamut. However, a red–green-inverted [red?+?green] model largely retained the original information. In this color model, the intensity of blue becomes the indicator of darkness. As a complementary color model, a red–green–[red?+?green] color model was examined. The color model provided pseudo-color images carrying information on redness, greenness, and yellowness. By comparing grayscale images of a single color component such as key black for the pseudo-color models, the pseudo-color models were shown to provide measures that are dimensionally independent of one another. Thus, together with the original red–green–blue (RGB) color image, the pseudo-color images almost triple the amount of information carried by the grayscale images. These multidimensional pieces of information are expected to facilitate the observation of colors of plants through digital image acquisition.     

Edge‐adaptive color interpolation for complementary color filter array

Complementary color filter array (CCFA) is widely used in consumer‐level digital video cameras, since it not only has high sensitivity and good signal‐to‐noise ratio in low‐light condition but also is compatible with the interlaced scanning used in broadcast systems. However, the full‐color images obtained from CCFA suffer from the color artifacts such as false color and zipper effects. These artifacts can be removed with edge‐adaptive color interpolation (ECI) approaches which are generally used in primary color filter array (PCFA). Unfortunately, the unique array pattern of CCFA makes it difficult that CCFA adopts ECI approaches. Therefore, to apply ECI approaches suitable for CCFA to color interpolation is one of the major issues to reconstruct the full‐color images. In this paper, we propose a new ECI algorithm for CCFA. To estimate an edge direction precisely and enhance the quality of the reconstructed image, a function of spatial variances is used as a weight, and new color conversion matrices are presented for considering various edge directions. Experimental results indicate that the proposed algorithm outperforms the conventional method with respect to both objective and subjective criteria. © 2006 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 16, 92–102, 2006     

Optimized algorithm for the spatial nonuniformity correction of an imaging system based on a charge-coupled device color camera

We present an optimized linear algorithm for the spatial nonuniformity correction of a CCD color camera's imaging system and the experimental methodology developed for its implementation. We assess the influence of the algorithm's variables on the quality of the correction, that is, the dark image, the base correction image, and the reference level, and the range of application of the correction using a uniform radiance field provided by an integrator cube. The best spatial nonuniformity correction is achieved by having a nonzero dark image, by using an image with a mean digital level placed in the linear response range of the camera as the base correction image and taking the mean digital level of the image as the reference digital level. The response of the CCD color camera's imaging system to the uniform radiance field shows a high level of spatial uniformity after the optimized algorithm has been applied, which also allows us to achieve a high-quality spatial nonuniformity correction of captured images under different exposure conditions.     

颜色相似性度量在色差检测中的应用

针对彩色图像缺陷检测中存在的色差问题,在RGB与HSI颜色空间模型的基础上,应用颜色相似性度量的方法来量化一些关键指标,以达到色差识别的目的.实验表明,这种方法符合人眼颜色视觉的相似性判定规律,同时计算简单,易于实现.它不仅避免了复杂的颜色转换过程,而且还能满足颜色视觉特性,因而具有重要的实际意义.     

High-speed digital color imaging pyrometry

Temperature measurements of high-explosive and combustion processes are difficult to obtain due to the speed and environment of the events. To overcome these challenges, we have characterized and calibrated a digital high-speed color camera that may be used to measure the temperature of such events. A two-color ratio method is used to calculate a temperature using the color filter array raw image data and a graybody assumption. If the raw image data are not available, temperatures may be calculated from the processed images or movies, depending on proper analysis of the digital color imaging pipeline. We analyze three transformations within the pipeline (demosaicing, white balance, and gamma correction) to determine their effect on the calculated temperature. Using this technique with a Phantom color camera, we have measured the temperature of exploded C-4 charges. The surface temperature of the resulting fireball was found to rapidly increase after detonation, and subsequently decayed to a constant value of approximately 1980 K.