掃描儀原理基本圖及像基礎知識課件

1、掃描儀的基本知識黃亮上海中晶科技有限公司Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.色彩基礎加色系統(tǒng)模式- RGB 色光相加R + G + B = WR + G = YR + B = MG

2、 + B = CEvaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.數(shù)字圖像所使用的色彩空間直射光的三原色：紅、綠、藍RedGreenBlue印刷油墨的三原色：青、洋紅、黃CyanMagentaY

3、ellowEvaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.數(shù)字圖像主要分為兩類光柵圖(點陣圖) 與矢量圖Evaluation only.Created with Aspose.Slides f

4、or .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.光柵圖像的特點光柵圖是由彼此相鄰的彩色像素所組成。最大的優(yōu)點是非常適合于表現(xiàn)連續(xù)調(diào)變化的各種景色、人物等自然模擬信息，并能夠做到從顏色和層次的各個方面來完美的再現(xiàn)它們。每個點稱為Pixel,如果采用RGB分三個字節(jié)來分別代表這個像素

5、的顏色值，其數(shù)據(jù)量是很大的。Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.光柵圖像的參數(shù)每個點稱為Pixel,所采用的記錄方式黑白：1 bit = 2 階灰度：8 bit = 256 階25

6、6色：8 bit Index Mode ( 需 Color Table )RGB真彩：RGB三個通道,每通道用 8bit表示 共 24 bit = 1677 萬色CMYK：打印、印刷時一般采用 32bitEvaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyr

7、ight 2004-2011 Aspose Pty Ltd.矢量圖的特點矢量圖是由一個一個相互獨立的圖形對象組合而成。這些圖形對象又是由標記點、線條、面、體等幾何元素和填充色、填充圖案所構成。矢量圖的特點在于文件容量可以很小。一般矢量圖顯示在計算機上或者打印出來，都是存在一個矢量到光柵的轉化過程。由于矢量圖在輸出的最后時刻，進行光柵化，則輸出圖像 的邊緣會很清晰和光滑。Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.

8、Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.什么是掃描儀及掃描儀的分類掃描儀是用于將照片、幻燈片或手繪原稿轉換為能被計算機處理的數(shù)據(jù)的輸入設備。三大類：點掃 - 滾筒掃描儀，采用PMT（光電倍增管） ，精度高、質量好，工作效率低。線掃 - 平臺掃描儀，采用CCD（電荷耦合器件），工作效率高、精度質量可以。面掃 - 數(shù)碼相機采用CCD、CMOS，精度低，色彩差。Evaluation only.Created wit

9、h Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.掃描儀工作原理框圖稿件光源CCD濾色鏡CCDAnalog-to-DigitalConverterPixelEvaluation only.Created with Aspose.Slides for

10、 .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.8K x 3 Color CCDBlueGreenRed圖像傳感器CCD (Charge Coupled Device光電耦合器)結構Evaluation only.Created with Aspose.Slides for .NET

11、 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.接觸式圖像傳感器-CISCIS -Contact Image Sensor圖像傳感組件，內(nèi)置LED光源，柱形透鏡，和傳感元件Evaluation only.Created with Aspose.Slides for .NET 3.5 Clien

12、t Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.CIS 與 CCD差別CIS內(nèi)置光源（彩色CIS內(nèi)置R、G、B三色光源）1：1直接感應圖像信息彩色掃描需要三次曝光正焦的成像的景深短，改善的方法是加強光源的強度。CCD由外部提供全光譜光源通過由反射鏡條和透鏡將圖像信息縮小后傳遞到CCD上。彩色CCD采用三線陣鍍膜技

13、術掃描可以一次曝光。正焦的成像的景深長，可掃描立體物。Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.分辨率分辨率用于測量一臺設備能記錄或生成的空間細節(jié)精度。分辨率越高，細節(jié)越精細。分辨率單位

14、為單位長度內(nèi)的元素數(shù)，例如：每英寸像素是顯微鏡、掃描儀和屏幕的分辨率單位 每英寸激光元素是打印機和激光照排機的分辨率單位。光學分辨率 (Optical Resolution)是掃描儀內(nèi)部器件CCD在原稿上能取得的元素數(shù)。Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0

15、.0.Copyright 2004-2011 Aspose Pty Ltd.掃描儀的光學分辨率掃描寬度 = 8.0具有 8000 點元素的 CCDLens掃描儀之光學分辨率=掃描儀采用的 CCD 點數(shù)掃描儀的最大掃描寬度 ( 英寸 )8000 pixels8.0= 1000 ppiEvaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides fo

16、r .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.考大家一個問題SM3830，1200DPI， A4幅面是8.5英寸那么CCD有多少個像素點？正確答案：1200X8.5=10200pixelEvaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for

17、.NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.掃描儀橫向分辨率與縱向分辨率掃描儀的橫向分辨率由掃描儀所采用的CCD元件的像素數(shù)與掃描幅面寬度之比所決定。掃描儀的縱向分辨率由掃描儀所采用的傳動機構所實現(xiàn)的步數(shù)與掃描幅面長度之比所決定。由于傳動機構可以通過一些措施來實現(xiàn)更微小的步距，所以一般掃描儀的縱向分辨率比橫向分辨率高一倍， 如12002400DPI，24004800DPIEvaluation only.Created with Aspose.Slides for .NET 3.5 Client Profi

18、le .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.光學分辨率與最高分辨率光學分辨率為掃描儀硬件設計上真正能達到的掃描分辨率最高分辨率為經(jīng)過軟件插值運算后掃描儀所提供的分辨率600DPI光學精度直接1200DPI應用1200DPI插值精度1200DPI光學精度Evaluation only.Created with Aspose.

19、Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.光學分辨率與插值分辨率 比較光學分辨率掃描意味著掃描的結果中每一個圖素信息都是實際的信息.光學分辨率取決于掃描儀結構,是掃描儀關鍵技術指標.相同的分辨率條件下,由實際光學分辨率掃描的圖像具有更多的細節(jié).插值分辨率掃描

20、意味著掃描的結果中有某些圖素的信息不是實際的信息.插值分辨率是根據(jù)光學分辨率通過運算而得到的.插值分辨率在某些場合使用低精度的圖像時,有利于消除應用中的馬賽克現(xiàn)象.但是圖像中沒有更多的細節(jié).Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 20

21、04-2011 Aspose Pty Ltd.一個大家容易疏忽的問題掃描儀的分辨率越高，掃描的品質就越好？Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.糾正錯誤觀念掃描儀的分辨率越高，掃描的

22、品質就越好？不正確掃描儀的分辨率高或低，與掃描品質無關掃描儀的分辨率越高，表示其放大倍率越高好的掃描儀要有好的影像解析能力，掃描品質才會提高好的掃描品質決定于掃描儀的動態(tài)密度和掃描人員的專業(yè)經(jīng)驗Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright

23、2004-2011 Aspose Pty Ltd.何時才會真正用到高分辨率掃描使用黑白模式掃描文字稿件，而直接要用來印刷時，用 1200 dpi 或 600 dpi 掃描。掃描影像圖形而需放大打印時例如掃描分辨率 600 dpi，放大倍率 200%；則實際上掃描儀本身是用 1200 dpi 在掃描Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.S

24、lides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.色彩位數(shù)與色彩表達范圍的關系21222324282161 bit2 bit3 bit4 bit8 bit16 bit2階4階8階16階256階65,536階 彩色是由RGB三色構成，一個36位的彩色圖是由12bit的藍色紅色綠色組合而成，構成2 X 2 X 2 =2 種色彩12121236Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile

25、.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.掃描儀的色彩位數(shù)掃描儀的色彩位數(shù)取決于掃描儀的模擬數(shù)字轉換器的位數(shù)。如A/D轉換的位數(shù)是16BIT，則掃描儀的色彩位數(shù)是48BIT。為何需要高比特的色彩位數(shù)？目前顯示卡采用的色彩位數(shù)最多的16位、24位。一般操作中也只是在用百萬色，億萬色有何好處？Evaluation only.Created wi

26、th Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.圖像的階調(diào)分布圖 階調(diào)分布圖是一種統(tǒng)計圖：表現(xiàn)出在一幅圖像上，不同的亮度值的分布情況。（在photoshop圖像菜單下的直方圖項）色階 (亮度 )點數(shù)Evaluation only.Created

27、 with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.由階調(diào)分布圖觀察色階是否連續(xù)有許多亮度的點數(shù)為 0表示色調(diào)不連續(xù)實際上并不足256 階色調(diào)連續(xù)完整的256 階Evaluation only.Created with Aspose.Slid

28、es for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.由階調(diào)分布圖觀察色階影像中沒有一個圖素的亮度超過 230表示實際只有230階可能是掃描儀偏暗或原稿偏暗影像中沒有一個圖素的亮度低于25表示實際只有 230階可能是掃描儀偏亮或原稿偏亮Evaluation only.Creat

29、ed with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.圖像的分析工具-直方圖分析高調(diào)照片，在直方圖工具中明顯看出高光部位的圖像信息很多。Evaluation only.Created with Aspose.Slides for .NET

30、3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.圖像的分析工具-直方圖分析低調(diào)照片，在亮度通道內(nèi)，在接近黑色的情況下，有很大比例的圖像信息存在于接近暗部的地方Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profil

31、e .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.圖像的分析工具-直方圖分析圖像在高光、暗調(diào)的部分信息分布比較均勻。所以此幅圖片是一幅中調(diào)的圖片。Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004

32、-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.高比特掃描的優(yōu)點Source image24-bit scan36-bit scan下方的圖表顯示同一稿件經(jīng)由 24 比特與 36比特掃描的結果圖中可看出圖像由最暗至最亮之間的層次分布Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile 5.

33、2.0.0.Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.曲線修正 ( Curve )修正前亮度修正前亮度修正后亮度修正后亮度Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty L

34、td.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.修正前0 1 2 3 4 5 6 7 8 9修正后修正前98765432100 1 2 3 4 5 6 7 8 90 1 2 3 4 5 6 7 8 9修正后曲線修正 ( Curve )Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2

35、004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.由階調(diào)分布圖看曲線修正后的損失修正前0 1 2 3 4 5 6 7 8 90 1 2 3 4 5 6 7 8 9修正后修正前 修正后Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-20

36、11 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.考大家一個問題scanwizard驅動軟件中，曲線修正可以提高亮度， 還有亮度欄也可以提高亮度，兩個方法有什么不同呢？是不是一樣的呢？Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 As

37、pose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.圖片層次的調(diào)整層次未動暗部提高表現(xiàn)重點在下方的草原Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspos

38、e.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.圖片層次的調(diào)整層次未動高光壓低表現(xiàn)重點在上方的雪山Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Co

39、pyright 2004-2011 Aspose Pty Ltd.48-bit 掃描儀的優(yōu)點48-bit 為 R / G / B 各16-bit 所組成，也就是說紅綠藍三色的層次都可區(qū)分為 2 = 65536 階影像修正時當然也會造成色彩層次上的損失，但由于原始資料高達 65536 階，而最后輸出時只需 256 階，因此在轉換為 256 階之前，即使做極大的修正，所剩余的階數(shù)仍超過256 ，在最后轉換為 256 階時都仍可得到完整的 256 階色彩層次注意photoshop支持256 階色彩層次最好，即24位16Evaluation only.Created with Aspose.Slide

40、s for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.掃描儀的接口方式-SCSISCSI，是Small Computer Standard Interface的縮寫，優(yōu)點：允許多個讀寫請求同時進行而無須排隊等候，從而讓總線更有效率，整體性能高。傳輸速度高，工作穩(wěn)定。最新標準的傳輸

41、速度已經(jīng)達到40MB/S。同一主控設備可以連接7個設備，每個設備擁有一個獨立的SCSI ID（范圍0-6）。MICROTEK掃描儀配置的SCSI卡有：標準：AVA1505(ISA)，AVA2903(PCI)、ADVSYS 3902(PCI)。MICROTEK目前有X12usl為SCSI和USB1.1雙接口，還有9600 xl，再就是高端掃描儀。Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation on

42、ly.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.掃描儀的接口方式-EPPEPP，增強型并行口，Enhanced Parallel Port ，優(yōu)點是：并口的傳輸速度是原標準并口SPP的四倍以上，達900KB/S。在PC上具有連接外設時，不用插卡，就可快速聯(lián)機。EPP標準在MICROTEK的低檔掃描儀中普遍采用。已淘汰Evaluation only.Created with Aspose.Slides for .NET 3.5 Client P

43、rofile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.掃描儀的接口方式- USB1.1USB，通用串行總線，Universal serial bus，特點：結構簡單，只有四條聯(lián)線（V+、V-、+5V、Gnd）。傳輸速度快，最高可達12MB/S。最多可支持127個外接設備。支持熱插拔（外設安裝或移機時，主機不用重新啟動）。PC

44、/MAC的操作平臺上都支持。MICROTEK目前有3830、4900、f5、f8、5600 USB產(chǎn)品已成掃描儀的主流。Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.掃描儀的接口方式- US

45、B2.0自從1995年對于USB接口的初步使用，這項技術如今已獲得全世界的認可。這項規(guī)格至今已發(fā)展成USB2.0，也就是通常所說的高速USB2.0，帶寬增強至原USB1.1的40倍并兼容USB1.1的設備、電纜和HUB。Microtek中晶采用高速USB以保持其產(chǎn)品線與最新科技的一致。目前產(chǎn)品有：ScanMaker 4100ScanMaker 5900ARTIX 1010+ 等Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty

46、Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.掃描儀的接口方式- IEEE1394 400MB/s的數(shù)據(jù)傳輸率和同時支持63個設備的能力使得IEEE1394接口適合所有的多媒體設備。根據(jù)內(nèi)置的實時數(shù)據(jù)傳輸協(xié)議，火線接口能適配許多的視頻，音頻設備。專業(yè)的音樂設備和游戲操縱桿同樣可以使用火線接口。 和同樣適用廣泛的USB接口比較，火線勝在在價格提高不多的前提下能有30倍的傳輸速度提升；而和傳統(tǒng)的SCSI總線對比

47、，火線支持熱插拔，我們不必中斷計算機的運行就能插拔設備。目前產(chǎn)品有：ScanMaker 6700ScanMaker 8700ARTIX 1010+等Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Lt

48、d.掃描儀的掃描幅面掃描幅面是用戶選擇掃描儀一個參考指標常見的反射稿掃描范圍：A4：8.511.7英寸（215.9 297.2mm）A4加長： 8.514英寸（216 355mm） A3： 1217英寸（304.8 431.8mm）常見的透射稿掃描范圍：雙平臺SM4、SM8700：810英寸（203.2 254mm）LightLid：5 6英寸（127 152.4mm）LightLid35：35mmMTMA： 7 9英寸鉆石瓏燈箱： 45英寸A3： 11 15英寸（279.4 381mm）Evaluation only.Created with Aspose.Slides for .NET 3

49、.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.色彩密度范圍值 ( Dynamic Range )高色彩位數(shù)并不意味著有高的掃描色彩品質，其中實際有效的色彩位數(shù)才是決定掃描品質的關鍵因素。由掃描儀實際能記錄的色階范圍，得到掃描儀的色彩密度范圍，也即掃描儀在色彩上的分辨能力。最暗最亮不同掃描儀在暗部

50、色分辨能力上的差異Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.色彩密度范圍值 ( Dynamic Range )Evaluation only.Created with Aspose.Sl

51、ides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.濃度范圍即原稿最暗點濃度值 (Dmax) 與原稿最亮點濃度值 (Dmin) 之間的差值一般用 D 來代表濃度范圍不同的原稿有不同的濃度范圍印刷稿= 1.9D沖印相片 = 2.3D正片（幻燈片、反轉片） = 4.0D一般底

52、片（負片）=1.7-1.9D色彩密度范圍值 ( Dynamic Range )Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.通常在接近純白到純黑的范圍。一臺具有良好密度值的掃描儀，可以正確的

53、捕捉各種色調(diào)的層次并直接輸出，如此可得到更多的影像細節(jié)。相反，一臺密度值較小的掃描儀，無法檢測到范圍足夠寬的色調(diào)層次，它將無法分辨出來影像的暗部層次，或損失亮部區(qū)域的細節(jié)，從而不能正確反映真實色彩。從而獲得高品質掃描圖像的另一個重要因素就是掃描儀本身的密度值指標。色彩密度范圍值 ( Dynamic Range )Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with

54、Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.掃描儀的軟件接口-TWAIN早期掃描儀廠家需要開發(fā)獨立的軟件來控制掃描儀，如果掃描儀的型號有變化，就需要重新寫程序。為使應用軟件與掃描儀之間能夠直接傳遞資料，從而由Microtek、Adobe、Aldus（后與Adobe合并）廠家制定出一個軟件工業(yè)的標準-TWAIN。使掃描儀廠家只要關心編寫遵守此標準的驅動程序，而不必編寫圖像處理軟件。圖像處理軟件則由專業(yè)的軟件公司來完成。TWAIN的推出，大大地方便了掃描儀的應用。Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.Evaluation only.Created with Aspose.Slides for .NET 3.5 Client Profile .Copyright 2004-2011 Aspose Pty Ltd.掃描稿件的類型不同的稿件需要采用不同的光源照射的方式。一般的印