清洁相机的感光元件

如果数码相机的感光元件上有灰尘,就会在照片上留下黑点和污迹。很多人不敢自己清理感光元件,下面我们将详细地教你如何在不伤及感光元件的情况下,将你的相机清理干净。翻译：林舒迪编辑：林曦在胶片摄影中,镜头上的污点就让很多摄影师伤透脑筋,现在数码相机上的脏点也非常烦人。虽然我们可以在Photoshop中进行修补,这非常费时。如果能在前期避免,     

专业快捷清洁感光元件

感光元件是数码相机的核心部件,虽然“藏在深宫”,但是依然会受到尘土、污渍的骚扰。一幅漂亮的照片可能会因为几个污点变成废片。所以我们必须及时清洁感光元件上的脏东西。虽然很多数码相机都带有感光元件清洁功能,但是它们的效果完全不能满足我们的要求。一套效果专业、使用简便的清洁工具是非常有必要的。这里我们教大家使用绿洁的清洁套装为相机清洁感光元件。     

什么是相机感光元件？

数码相机的感光元件相当于传统相机的胶片,在拍摄中起到了至关重要的作用。这个部件承担着接收和分析光线的大任,了解它才能了解数码相机的本质。除了焦距转换系数和像素数,你还应该了解更多知识。     

什么是相机感光元件？

数码相机的感光元件相当于传统相机的胶片,在拍摄中起到了至关重要的作用。这个部件承担着接收和分析光线的大任,了解它才能了解数码相机的本质。除了焦距转换系数和像素数,你还应该了解更多知识。     

彩色电影负片感光特性曲线的Logistic模型

应用Logistic模型对彩色电影负片的D lgH感光特性曲线进行拟合 ,并计算相关的照相性能参数。统计分析结果表明 ,其分层曲线的拟合优度分别为σDR=0 0 2 4 7,σDG=0 0 0 80 ,σDB=0 0 2 5 9。相关的照相性能参数的计算精度 ,亦达到了国际标准化组织 (ISO)所要求的标准。     

微机自动制图在感光测定中的应用

通过微机对X Rite 36 1T密度计 (以下简称密度计 )测出的光楔密度进行自动显示和处理 ,画出感光特性曲线 ,并计算出特性曲线的反差系数γ及感光度S。通过与标准值进行比较分析 ,可对显影液各成分的调整起指导作用     

Concerning the calculation of the color gamut in a digital camera

Several methods to determine the color gamut of any digital camera are shown. Since an input device is additive, its color triangle was obtained from their spectral sensitivities, and it was compared with the theoretical sensors of Ives‐Abney‐Yule and MacAdam. On the other hand, the RGB digital data of the optimal or MacAdam colors were simulated to transform them into XYZ data according to the colorimetric profile of the digital camera. From this, the MacAdam limits associated to the digital camera are compared with the corresponding ones of the CIE‐1931 XYZ standard observer, resulting that our color device has much smaller MacAdam loci than those of the colorimetric standard observer. Taking this into account, we have estimated the reduction of discernible colors by the digital camera applying a chromatic discrimination model and a packing algorithm to obtain color discrimination ellipses. Calculating the relative decrement of distinguishable colors by the digital camera in comparison with the colorimetric standard observer at different luminance factors of the optimal colors, we have found that the camera distinguishes considerably fewer very dark than very light ones, but relatively much more colors with middle lightness (Y between 40 and 70, or L* between 69.5 and 87.0). This behavior is due to the short dynamic range of the digital camera response. © 2006 Wiley Periodicals, Inc. Col Res Appl, 31, 399–410, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20245     

A study of digital camera colorimetric characterization based on polynomial modeling

The digital camera is a powerful tool to capture images for use in image processing and colour communication. However, the RGB signals generated by a digital camera are device‐dependent, i.e., different digital cameras produce different RGB responses for the same scene. Furthermore, they are not colorimetric, i.e., the output RGB signals do not directly correspond to the device‐independent tristimulus values based on the CIE standard colorimetric observer. One approach for deriving a colorimetric mapping between camera RGB signals and CIE tristimulus values uses polynomial modeling and is described here. The least squares fitting technique was used to derive the coefficients of 3 × n polynomial transfer matrices, yielding a modeling accuracy typically averaging 1 ΔE units in CMC(1:1) when a 3 × 11 matrix is used. Experiments were carried out to investigate the repeatability of the digitizing system, characterization performance when different polynomials were used, modeling accuracy when 8‐bit and 12‐bit RGB data were used for characterization, and the number of reference samples needed to achieve a reasonable degree of modeling accuracy. Choice of characterization target and media and their effect on metamerism have been examined. It is demonstrated that a model is dependent upon both media and colorant, and applying a model to other media/colorants can lead to serious eye–camera metamerism problems. © 2001 John Wiley & Sons, Inc. Col Res Appl, 26, 76–84, 2001     

CMOS数字图像传感器与照相机技术——信息记录材料在成像领域的技术进展(五)

CMOS图像传感器是数字图像技术系统的核心器件 ,是继CCD图像传感器问世 30年后的又一产品。分析了CMOS图像传感器的工作原理及其性能特点并与CCD图像传感器结构、内部特性、工艺、成本等作了系统的比较。     

The optimal number of sensors for a digital imaging system from the perspective of metamer mismatching

Metamer mismatching occurs in both the human visual system and digital imaging systems. Increasing the number of sensors in digital imaging systems is an efficient method to reduce the degree of metamer mismatching. This study investigates the number of sensors that are needed for the digital imaging systems to have a similar ability to the human sensor system in distinguishing colors from the perspective of metamer mismatching. Optimal spectral reflectance was generated, and a dataset with more than 47 million previously collected practical spectral reflectance functions was used to derive the metameric color pairs. Different sets of Gaussian-shaped functions were designed to model the spectral sensitivity functions of the digital imaging systems. Both the metamer mismatching volumes and color differences were used to characterize the degree of metamer mismatching for pairs of samples, which were metameric to the imaging systems but appeared different to the human sensor system. The results show that the practical metamer mismatching volumes are substantially smaller than the theoretical ones. The results also show that both the metamer mismatching volumes and color differences are significantly reduced by increasing the number of sensors from three to five for the digital imaging system but are only slightly reduced by further increasing the number of sensors from five to seven. This indicates that five sensors is an efficient and optimal solution for an imaging system with Gaussian-shaped sensors to have a similar ability in distinguishing colors compared to the human sensor system.     

Determining colour gamuts of digital cameras and scanners

The determination of the colour gamuts of colour reproduction media is an important aspect of both understanding them in isolation and using them in the context of a colour reproduction system. Although this is well understood for output colour reproduction media, a solution for input media is not to be had in a simple way. To this end, in this article, we propose a method based on simulating the responses of an input medium to given spectral power distributions. We then determine the gamut of an input medium on the basis of having a set of spectra that covers the majority of all possible spectra, knowing a medium's quantized responses to them, and then determining a boundary beyond which the medium does not produce variation in its responses. © 2002 Wiley Periodicals, Inc. Col Res Appl, 28, 59–68, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.     

Optimal selection of representative samples for efficient digital camera-based spectra recovery

For digital camera-based spectra recovery, the spectral reflectance of the object being imaged always needs to be accurately recovered using training samples from available database. Considering the heavy workload when using all samples in database as training samples in practice, a new representative samples selection method is proposed for efficient digital camera-based spectra recovery based on single RGB image. The representative simulation system is firstly constructed through correlation analysis of spectra recovery results of different systems, and based on the representative simulation system, a few number of representative samples are selected from the database based on minimum of the defined simulate spectra recovery error. The effectiveness of the proposed method is evaluated and compared with existing method. As the results show, the proposed method outperforms the existing methods, and the robustness of the selected representative samples is consistent with the database in practical applications.     

Camera color analysis gamut

Michael Brill has opened a valuable discussion about camera gamuts and Roy Berns has questioned the use of the word “gamut” in that proposal. We would like to stress the importance of associating a gamut with an imaging output device and would thus question the use of the concept proposed for assessing the capabilities of an input device. © 2007 Wiley Periodicals, Inc. Col Res Appl, 33, 81–82, 2008     

乙烯环氧化反应器操作参数敏感性分析

采用乙烯环氧化制取环氧乙烷单管一维数学模型计算和实验,研究乙烯环氧化反应操作参数如原料入口温度、冷却介质温度、总传热系数、空速以及入口乙烯、氧和二氧化碳体积分数对列管式反应器轴向热点温度分布和转化率、选择性的影响.结果表明:冷却介质温度、空速以及总传热系数对反应器热点温度有较大影响.在原料入口温度120-210℃、乙烯...     

数字分析技术在耐火材料岩相分析中的应用

以熔铸33#AZS材料(取6个试样)作为试验对象,按标准检测各试样的化学组成和其他性能(玻璃相初析温度、24 h侵蚀量、玻璃相渗出量、体积密度),采用配有增强背散射探头的扫描电子显微镜拍摄各试样的低倍背散射电子像(各3张)。接下来,首先对各图像进行处理,并通过计数求得各试样的物相组成(气孔、基质、铝锆共析体和一次斜锆石的相对含量);其次,计算得到熔铸33#AZS材料各参数数据之间的相关系数,并采用F检验剔除不显著的系数和不重要的变量;再次,利用路径分析建立33#AZS材料各主要参数之间的关系;最后,运用专业知识解释这些关系,得到关于熔铸耐火材料工艺的有益结论。