打印機外文翻譯--奧普蒂化的光譜紐格伯爾模型打印機特性

1、<p><b>　　畢業(yè)設(shè)計/論文</b></p><p>　　外 文 文 獻 翻 譯</p><p>　　系 別 信息科學(xué)與技術(shù)系 </p><p>　　專 業(yè) 班 級 通信工程 </p><p>　　姓 名

2、 </p><p>　　評 分 </p><p>　　指 導(dǎo) 教 師 </p><p>　　奧普蒂化的光譜紐格伯爾模型打印機特性</p><p>

3、<b>　　摘要</b></p><p>　　一個比色打印機需以其注入的一組油墨，預(yù)測由此產(chǎn)生的印刷顏色，通過反射或刺激值指定。該紐格伯爾模式已被廣泛用于預(yù)測的半色調(diào)彩色打印機色反應(yīng)。本文是介紹和比較優(yōu)化紐格伯爾模型的技術(shù)。這些措施包括尼爾森因素的優(yōu)化，這歸因于光的散射及估計該點區(qū)域并擴展到精確位置的功能。一種新的技術(shù)描述了優(yōu)化紐格伯爾初選使用加權(quán)譜回歸。實驗結(jié)果提出了它使用兩個半色調(diào)屏幕：

4、隨機靜電打印機或旋轉(zhuǎn)點，和互聯(lián)網(wǎng)上點屏幕。使用尤爾一尼爾森因子，細微的的框架，并使譜回歸模型的準確度大大提高。</p><p><b>　　1引言</b></p><p>　　比色打印機特性要求是建立在信號的輸入到打印機和由此產(chǎn)生的印刷顏色的色度測量的關(guān)系上的。這種關(guān)系，我們稱之為打印機特性的功能，往往是得到了印刷和測量補丁的色彩大量運用了一些在已知的樣本的測量插值。

5、另一種方法近似于用打印機型號的特征函數(shù)。試圖模擬打印機經(jīng)常會產(chǎn)生有價值的直覺的基本物理過程，它在光，色彩和紙之間產(chǎn)生復(fù)雜的相互作用。模型的實際優(yōu)點是打印機可以實現(xiàn)定性并相對較少的測量。打印機的模型精度顯然取決于模型中的假設(shè)是否正確。</p><p>　　該紐格伯爾模型已廣泛用于二進制模式的彩色打印機并可采用各種色調(diào)屏幕。原始模型實質(zhì)上是Murray-Davies equation（用于預(yù)測灰度反射）的色彩方法。打

6、印機字的顏色由紅綠藍（RGB）三色組合，預(yù)計作為對固體套印的RGB值加權(quán)平均印刷；青色，品紅和黃色的印刷，由地區(qū)覆蓋范圍相對點的權(quán)重決定。在這里，R，G，B可能被認為是從印刷補丁反射光，通過3個已知光譜靈敏度的職能通過寬帶過濾器，超過估計所有在五個可見光波長范圍內(nèi)的方法，從該地區(qū)的覆蓋范圍數(shù)字輸入色調(diào)，包括一些直接測量和計算的結(jié)合。</p><p>　　請注意，盡管這種模式提供設(shè)備值（CMY）的特征函數(shù)（三原色）

7、色值，它是從色值到設(shè)備空間，最終是為了尋求色彩再現(xiàn)逆映射。幾位研究人員討論了反相的紐格伯爾方程。這個反演問題是一個非線性問題，可以解決在三個輸入著色劑的情形C，M，Y，通過迭代方法。當(dāng)著色劑數(shù)量超過3，問題就變得病態(tài)數(shù)著色劑組合可以導(dǎo)致生成相同的測量顏色。在這項工作中，只有前進定性問題的審查。筆者認為，一旦提出一個精確的模型，樣品的高密度，導(dǎo)出等多層面的擬合和插值技術(shù)可以很容易被用來顛倒模式。 </p><p&g

8、t;　　各種方法已經(jīng)被提出了提高原紐格伯爾方程的準確性。一個重要的現(xiàn)象，不占原模型，光散射的文件內(nèi)。Yule and Nielsen 通過模型中的一個額外的參數(shù)方程紐格伯爾這種效果。其他研究人員提出了在之間的透射模式和一紙點擴散函數(shù)（PSF）的回旋空間光散射的形式更復(fù)雜的模型。尼爾森參數(shù)不明確的空間變化之間的相互作用光紙帳戶，有人建議由魯克德舍爾和豪澤，一個簡單的關(guān)系可能與這個簡單的模型和滌綸短纖存在的模型。維賈諾表明，而不是在紐格伯爾

9、方程形式的收益率更高的精度寬帶頻譜。這一發(fā)現(xiàn)證實了作者。 Engeldrum表明，無論是紙張和圓點的顏色相對點區(qū)域覆蓋范圍內(nèi)的功能，并延長了紐格伯爾模型交代。利用該紐格伯爾方程的幾何解釋，開發(fā)了蜂窩Hueberger盧哥貝爾模式，即除固體套印顏色來計算最終輸出的顏色。蜂窩技術(shù)將被視為在本文件。從德米歇爾的假設(shè)出發(fā)點區(qū)域覆蓋范圍內(nèi)，并用序列二次規(guī)劃方法來估計這些參數(shù)。探討了波長依賴尤爾使用尼爾森的因素。 </p><p

10、>　　在這項工作中采取的做法是，以符合理想打印機的紐格伯爾模型的基本形式，并提供優(yōu)化模型的參數(shù)，以便更好地適應(yīng)實際打印機的特性的數(shù)學(xué)技術(shù)。因此，該模型簡單保留，而其精度提高。優(yōu)化的圣誕-尼爾森因素，技術(shù)點區(qū)域功能，細胞模型已被提交會議的出版物上發(fā)表。本文介紹這些技術(shù)在一個比較一致的框架。此外，由在最近的一次會議報告的作者提出譜回歸的新方法，更詳細。實驗結(jié)果提出了兩種類型的半色調(diào)屏幕：隨機或旋轉(zhuǎn)點，和互聯(lián)網(wǎng)上點屏幕上。 &l

11、t;/p><p>　　2紐格伯爾混合模型。</p><p>　　二進制打印機，一個多種顏色的渲染，是通過不同的組合達到點著色劑的主要地區(qū)覆蓋范圍。在紐格伯爾方程'預(yù)測從任意作為一種已知的基礎(chǔ)上為2n的色彩，光譜反射加權(quán)平均印刷補丁的平均光譜反射率，其中N是系統(tǒng)著色劑數(shù)量。在這項工作中的N = 3 CMY打印機案件將用來描述各種模型。方程很容易推廣到N著色劑，而事實上，青色，洋紅色，黃色

12、，黑色（CMYK）打印機將在實驗結(jié)果中。</p><p>　　對于CMY打印機，有8個的基礎(chǔ)上的顏色，這是白皮書（寬）和1，2和3純色覆蓋（即0％和C，男，y的100％的組合），這些基礎(chǔ)色將稱為紐格伯爾初選。在原來的紐格伯爾方程，預(yù)測的顏色是由三個寬帶代表短期，中期反射和電磁波譜的長波長部分指定。在這項工作中，窄帶反射光譜住宅（十）使用，而不是他們的寬帶同行，因為前者一般收益率更高的準確性。</p>

13、<p>　　3結(jié)論 本文幾個打印機的紐格伯爾方程的模型已被描述和比較。一種新的技術(shù)已提出了優(yōu)化光譜紐格伯爾初選使用最小二乘回歸。提供各種型號的復(fù)雜性和精確度之間不同的權(quán)衡。表1總結(jié)了在測量數(shù)量而言，這些權(quán)衡需要制定出一個給定的模式和結(jié)果的準確性。一般來說，模型的準確度是成正比的測量數(shù)目，但人們可以方便地識別報酬遞減的情況。產(chǎn)生的巨大收益來自使用尤爾一尼爾森改正，并可以在細胞框架或全球譜回歸模型。測量的數(shù)目增加的細胞

14、模型與細胞數(shù)量成倍的要求，同時在準確增益減小。在34 = 81初選的情況常常是一個可以接受的折衷。在當(dāng)?shù)?，在計算成本的大幅增加加?quán)回歸結(jié)果（未顯示在表1），在沒有獲得準確對全球回歸。</p><p>　　在執(zhí)行回歸的數(shù)學(xué)解釋是，它提供了一個自由的模式（即初選額外的程度），因此適合優(yōu)越的經(jīng)驗數(shù)據(jù)。從初選的光譜，如無花果，陰謀的研究。 10和11，已經(jīng)從沒有測量，觀察到的趨勢回歸職能。因此，很難物理意義重視對這些陰謀

15、，除了指出，在選定的樣本良好的線性回歸可能會導(dǎo)致的光譜測量噪聲平均，從而得到更強大的預(yù)測。</p><p>　　這項工作提出了一些進一步的擴展。譜回歸應(yīng)用于蜂窩架構(gòu)可能會導(dǎo)致沒有額外的提高測量精度。阿譜初選的聯(lián)合優(yōu)化，點區(qū)域功能和尤爾一尼爾森因素可能導(dǎo)致對其中n因素是單獨優(yōu)化目前的做法更好的結(jié)果。這是身體有理由認為在光散射波長基板依賴，因此一個譜回歸模型，支持n是X的函數(shù)可能會導(dǎo)致更準確的模型的擴展。然而，重要的

16、是銘記之間的物理模型的復(fù)雜性和準確性實現(xiàn)權(quán)衡始終牢記實際打印系統(tǒng)。最后，這將是值得研究的印刷技術(shù)比其他如靜電復(fù)印，噴墨機，膠印機等更具有效性。</p><p>　　Opti ization of the spectral Neugebauer model for printer characterization</p><p><b>　　Abstract</b>&l

17、t;/p><p>　　A colorimetric printer model takes as its input a set of ink values and predicts the resulting printed color, as specified by re?flectance or tristimulus values. The Neugebauer model has been widely

18、used to predict the colorimetric response of halftone color printers. In this paper, techniques for optimizing the Neugebauer model are presented and compared. These include optimization of the Yule-Nielsen factor that a

19、ccounts for light scattering in the pa?per, estimation of the dot area functions,</p><p>　　1 Introduction</p><p>　　Color printer characterization requires that a relationship be established betw

20、een the input signals to the printer and the colorimetric measurements of the resulting printed colors. This relationship, which we call the printer characterization function, is often obtained by printing and measuring

21、a large number of color patches and applying some interpo?lation among the measurements at the known samples. An alternative approach is to approximate the characterization function with a printer mode</p><p&g

22、t;　　The Neugebauer model has been widely used to model binary color printers employing various halftone screens. The original model is essentially an extension of the Murray-Davies equation2 (used for predicting grayscal

23、e re?flectance) to the color case. The color of a print, in red?green-blue (RGB) coordinates, is predicted as a weighted average of the RGB values of the solid overprints of the three printing primaries, cyan, magenta, a

24、nd yellow (C, M, Y), where the weights are determined by the rel</p><p>　　Note that while the model provides the characterization function from device values (CMY) to colorimetric values (RGB), it is the inv

25、erse mapping from colorimetric to de?vice space that is ultimately sought for color reproduction. Several researchers have addressed the problem of invert?ing the Neugebauer equations.3-6 The inversion is a nonlin?ear pr

26、oblem that can be solved, in the case of three input colorants C, M, Y, by iterative approaches. When the num?ber of colorants exceeds three, the p</p><p>　　Various methods have been proposed for improving t

27、he accuracy of the original Neugebauer equations. An impor?tant phenomenon not accounted for in the original model is that of light scattering within the paper. Yule and Nielsen9 modeled this effect via an additional par

28、ameter in the Neu?gebauer equations. Other researchers10-12 have proposed more sophisticated models for light scattering in the form of a spatial convolution between the transmittance pattern and a paper point spread fun

29、ction (PSF</p><p>　　The approach taken in this work is to conform to the basic form of the Neugebauer model for an ideal printer, and to offer mathematical techniques for optimizing the parameters of the mod

30、el to better fit the characteristics of real printers. Thus the simplicity of the model is retained, while its accuracy is improved. Techniques for optimizing the Yule–Nielsen factor, dot area functions, and cellular mod

31、el have been published in previous conference publica?tions by the author.16'24 In this paper</p><p>　　The paper is organized as follows. In Sec. 2, the Neuge?bauer mixing model is briefly introduced, an

32、d is applied to the two types of halftone configurations. The light scatter?ing problem and Yule–Nielsen correction are described in Sec. 3. Methods for calculating the dot area functions are described in Sec. 4, and ext

33、ensions to the cellular frame?work are presented in Sec. 5. A spectral regression tech?nique is described in Sec. 6, where the Neugebauer prima?ries are themselves treated as param</p><p>　　2 Neugebauer Mixi

34、ng Model</p><p>　　or a binary printer, the rendering of a multitude of colors is achieved through combinations of varying dot area cov?erages of the primary colorants. The Neugebauer equations' predict t

35、he average spectral reflectance from an arbitrary printed patch as a weighted average of the spectral reflectances of 2N known basis colors, where N is the num?ber of system colorants. In this work, the case of N=3 for C

36、MY printers will be used to describe the various models. The equations are easily generalized t</p><p>　　2.3 Effect of Screen Design</p><p>　　One of the fundamental factors that affects model ac

37、curacy is the frequency of the halftone screen.".28 The ideal model assumes that the dots are rectangular in cross section, and hence result in a binary absorption profile as a function of spatial location. In reali

38、ty, dots have soft transitions from regions with full ink to regions with no ink. If the halftone screen frequency is relatively low, or a clustered dot is used, the relative area of the paper covered by the transition p

39、ected to be r</p><p>　　8 Conclusions</p><p>　　In this paper, several printer models based on the Neuge?bauer equations have been described and compared. A new technique has been proposed for opt

40、imizing the spectral Neugebauer primaries using least squares regression. The various models offer different tradeoffs between complex?ity and accuracy. Table 1 summarizes these tradeoffs in terms of the number of measur

41、ements required to derive a given model and the resulting accuracy. Generally, model accuracy is proportional to the number of measu</p><p>　　The mathematical interpretation of performing regres?sion is that

42、 it affords an extra degree of freedom in the model (i.e., the primaries), and hence a superior fit to em?pirical data. From a study of plots of the spectral primaries, such as Figs. 10 and 11, no trend has been observed

43、 from measured to regressed functions. Hence it is difficult to attach physical significance to these plots, other than to point out that linear regression over a well chosen sample set will likely result in an aver</

44、p><p>　　This work suggests several further extensions. Spectral regression applied to the cellular framework may lead to improvement in model accuracy with no additional mea?surements. A joint optimization of t

45、he spectral primaries, dot area functions, and Yule-Nielsen factor may lead to superior results over the current approach where the n fac?tor is optimized separately. It is physically plausible that the scattering of lig