扫描仪原理基本图及像基础知识课件

1、扫描仪的基本知识黄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.色彩基础加色系统模式- 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.数字图像所使用的色彩空间直射光的三原色：红、绿、蓝RedGreenBlue印刷油墨的三原色：青、洋红、黄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.数字图像主要分为两类光栅图(点阵图) 与矢量图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.光栅图像的特点光栅图是由彼此相邻的彩色像素所组成。最大的优点是非常适合于表现连续调变化的各种景色、人物等自然模拟信息，并能够做到从颜色和层次的各个方面来完美的再现它们。每个点称为Pixel,如果采用RGB分三个字节来分别代表这个像素

5、的颜色值，其数据量是很大的。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.光栅图像的参数每个点称为Pixel,所采用的记录方式黑白：1 bit = 2 阶灰度：8 bit = 256 阶25

6、6色：8 bit Index Mode ( 需 Color Table )RGB真彩：RGB三个通道,每通道用 8bit表示 共 24 bit = 1677 万色CMYK：打印、印刷时一般采用 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.矢量图的特点矢量图是由一个一个相互独立的图形对象组合而成。这些图形对象又是由标记点、线条、面、体等几何元素和填充色、填充图案所构成。矢量图的特点在于文件容量可以很小。一般矢量图显示在计算机上或者打印出来，都是存在一个矢量到光栅的转化过程。由于矢量图在输出的最后时刻，进行光栅化，则输出图像 的边缘会很清晰和光滑。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.什么是扫描仪及扫描仪的分类扫描仪是用于将照片、幻灯片或手绘原稿转换为能被计算机处理的数据的输入设备。三大类：点扫 - 滚筒扫描仪，采用PMT（光电倍增管） ，精度高、质量好，工作效率低。线扫 - 平台扫描仪，采用CCD（电荷耦合器件），工作效率高、精度质量可以。面扫 - 数码相机采用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.扫描仪工作原理框图稿件光源CCD滤色镜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图像传感器CCD (Charge Coupled Device光电耦合器)结构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.接触式图像传感器-CISCIS -Contact Image Sensor图像传感组件，内置LED光源，柱形透镜，和传感元件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 与 CCD差别CIS内置光源（彩色CIS内置R、G、B三色光源）1：1直接感应图像信息彩色扫描需要三次曝光正焦的成像的景深短，改善的方法是加强光源的强度。CCD由外部提供全光谱光源通过由反射镜条和透镜将图像信息缩小后传递到CCD上。彩色CCD采用三线阵镀膜技

13、术扫描可以一次曝光。正焦的成像的景深长，可扫描立体物。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.分辨率分辨率用于测量一台设备能记录或生成的空间细节精度。分辨率越高，细节越精细。分辨率单位

14、为单位长度内的元素数，例如：每英寸像素是显微镜、扫描仪和屏幕的分辨率单位 每英寸激光元素是打印机和激光照排机的分辨率单位。光学分辨率 (Optical Resolution)是扫描仪内部器件CCD在原稿上能取得的元素数。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.扫描仪的光学分辨率扫描宽度 = 8.0具有 8000 点元素的 CCDLens扫描仪之光学分辨率=扫描仪采用的 CCD 点数扫描仪的最大扫描宽度 ( 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.考大家一个问题SM3830，1200DPI， A4幅面是8.5英寸那么CCD有多少个像素点？正确答案：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.扫描仪横向分辨率与纵向分辨率扫描仪的横向分辨率由扫描仪所采用的CCD元件的像素数与扫描幅面宽度之比所决定。扫描仪的纵向分辨率由扫描仪所采用的传动机构所实现的步数与扫描幅面长度之比所决定。由于传动机构可以通过一些措施来实现更微小的步距，所以一般扫描仪的纵向分辨率比横向分辨率高一倍， 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.光学分辨率与最高分辨率光学分辨率为扫描仪硬件设计上真正能达到的扫描分辨率最高分辨率为经过软件插值运算后扫描仪所提供的分辨率600DPI光学精度直接1200DPI应用1200DPI插值精度1200DPI光学精度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.光学分辨率与插值分辨率 比较光学分辨率扫描意味着扫描的结果中每一个图素信息都是实际的信息.光学分辨率取决于扫描仪结构,是扫描仪关键技术指标.相同的分辨率条件下,由实际光学分辨率扫描的图像具有更多的细节.插值分辨率扫描

20、意味着扫描的结果中有某些图素的信息不是实际的信息.插值分辨率是根据光学分辨率通过运算而得到的.插值分辨率在某些场合使用低精度的图像时,有利于消除应用中的马赛克现象.但是图像中没有更多的细节.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.一个大家容易疏忽的问题扫描仪的分辨率越高，扫描的品质就越好？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.纠正错误观念扫描仪的分辨率越高，扫描的

22、品质就越好？不正确扫描仪的分辨率高或低，与扫描品质无关扫描仪的分辨率越高，表示其放大倍率越高好的扫描仪要有好的影像解析能力，扫描品质才会提高好的扫描品质决定于扫描仪的动态密度和扫描人员的专业经验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.何时才会真正用到高分辨率扫描使用黑白模式扫描文字稿件，而直接要用来印刷时，用 1200 dpi 或 600 dpi 扫描。扫描影像图形而需放大打印时例如扫描分辨率 600 dpi，放大倍率 200%；则实际上扫描仪本身是用 1200 dpi 在扫描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.色彩位数与色彩表达范围的关系21222324282161 bit2 bit3 bit4 bit8 bit16 bit2阶4阶8阶16阶256阶65,536阶 彩色是由RGB三色构成，一个36位的彩色图是由12bit的蓝色红色绿色组合而成，构成2 X 2 X 2 =2 种色彩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.扫描仪的色彩位数扫描仪的色彩位数取决于扫描仪的模拟数字转换器的位数。如A/D转换的位数是16BIT，则扫描仪的色彩位数是48BIT。为何需要高比特的色彩位数？目前显示卡采用的色彩位数最多的16位、24位。一般操作中也只是在用百万色，亿万色有何好处？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.图像的阶调分布图 阶调分布图是一种统计图：表现出在一幅图像上，不同的亮度值的分布情况。（在photoshop图像菜单下的直方图项）色阶 (亮度 )点数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.由阶调分布图观察色阶是否连续有许多亮度的点数为 0表示色调不连续实际上并不足256 阶色调连续完整的256 阶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.由阶调分布图观察色阶影像中没有一个图素的亮度超过 230表示实际只有230阶可能是扫描仪偏暗或原稿偏暗影像中没有一个图素的亮度低于25表示实际只有 230阶可能是扫描仪偏亮或原稿偏亮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.图像的分析工具-直方图分析高调照片，在直方图工具中明显看出高光部位的图像信息很多。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.图像的分析工具-直方图分析低调照片，在亮度通道内，在接近黑色的情况下，有很大比例的图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.图像的分析工具-直方图分析图像在高光、暗调的部分信息分布比较均匀。所以此幅图片是一幅中调的图片。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.高比特扫描的优点Source image24-bit scan36-bit scan下方的图表显示同一稿件经由 24 比特与 36比特扫描的结果图中可看出图像由最暗至最亮之间的层次分布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.曲线修正 ( 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修正后曲线修正 ( 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.由阶调分布图看曲线修正后的损失修正前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.考大家一个问题scanwizard驱动软件中，曲线修正可以提高亮度， 还有亮度栏也可以提高亮度，两个方法有什么不同呢？是不是一样的呢？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.图片层次的调整层次未动暗部提高表现重点在下方的草原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.图片层次的调整层次未动高光压低表现重点在上方的雪山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 扫描仪的优点48-bit 为 R / G / B 各16-bit 所组成，也就是说红绿蓝三色的层次都可区分为 2 = 65536 阶影像修正时当然也会造成色彩层次上的损失，但由于原始资料高达 65536 阶，而最后输出时只需 256 阶，因此在转换为 256 阶之前，即使做极大的修正，所剩余的阶数仍超过256 ，在最后转换为 256 阶时都仍可得到完整的 256 阶色彩层次注意photoshop支持256 阶色彩层次最好，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.扫描仪的接口方式-SCSISCSI，是Small Computer Standard Interface的缩写，优点：允许多个读写请求同时进行而无须排队等候，从而让总线更有效率，整体性能高。传输速度高，工作稳定。最新标准的传输

41、速度已经达到40MB/S。同一主控设备可以连接7个设备，每个设备拥有一个独立的SCSI ID（范围0-6）。MICROTEK扫描仪配置的SCSI卡有：标准：AVA1505(ISA)，AVA2903(PCI)、ADVSYS 3902(PCI)。MICROTEK目前有X12usl为SCSI和USB1.1双接口，还有9600 xl，再就是高端扫描仪。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.扫描仪的接口方式-EPPEPP，增强型并行口，Enhanced Parallel Port ，优点是：并口的传输速度是原标准并口SPP的四倍以上，达900KB/S。在PC上具有连接外设时，不用插卡，就可快速联机。EPP标准在MICROTEK的低档扫描仪中普遍采用。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.扫描仪的接口方式- USB1.1USB，通用串行总线，Universal serial bus，特点：结构简单，只有四条联线（V+、V-、+5V、Gnd）。传输速度快，最高可达12MB/S。最多可支持127个外接设备。支持热插拔（外设安装或移机时，主机不用重新启动）。PC

44、/MAC的操作平台上都支持。MICROTEK目前有3830、4900、f5、f8、5600 USB产品已成扫描仪的主流。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.扫描仪的接口方式- US

45、B2.0自从1995年对于USB接口的初步使用，这项技术如今已获得全世界的认可。这项规格至今已发展成USB2.0，也就是通常所说的高速USB2.0，带宽增强至原USB1.1的40倍并兼容USB1.1的设备、电缆和HUB。Microtek中晶采用高速USB以保持其产品线与最新科技的一致。目前产品有：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.扫描仪的接口方式- IEEE1394 400MB/s的数据传输率和同时支持63个设备的能力使得IEEE1394接口适合所有的多媒体设备。根据内置的实时数据传输协议，火线接口能适配许多的视频，音频设备。专业的音乐设备和游戏操纵杆同样可以使用火线接口。 和同样适用广泛的USB接口比较，火线胜在在价格提高不多的前提下能有30倍的传输速度提升；而和传统的SCSI总线对比

47、，火线支持热插拔，我们不必中断计算机的运行就能插拔设备。目前产品有：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.扫描仪的扫描幅面扫描幅面是用户选择扫描仪一个参考指标常见的反射稿扫描范围：A4：8.511.7英寸（215.9 297.2mm）A4加长： 8.514英寸（216 355mm） A3： 1217英寸（304.8 431.8mm）常见的透射稿扫描范围：双平台SM4、SM8700：810英寸（203.2 254mm）LightLid：5 6英寸（127 152.4mm）LightLid35：35mmMTMA： 7 9英寸钻石珑灯箱： 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.色彩密度范围值 ( Dynamic Range )高色彩位数并不意味着有高的扫描色彩品质，其中实际有效的色彩位数才是决定扫描品质的关键因素。由扫描仪实际能记录的色阶范围，得到扫描仪的色彩密度范围，也即扫描仪在色彩上的分辨能力。最暗最亮不同扫描仪在暗部

50、色分辨能力上的差异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.色彩密度范围值 ( 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.浓度范围即原稿最暗点浓度值 (Dmax) 与原稿最亮点浓度值 (Dmin) 之间的差值一般用 D 来代表浓度范围不同的原稿有不同的浓度范围印刷稿= 1.9D冲印相片 = 2.3D正片（幻灯片、反转片） = 4.0D一般底

52、片（负片）=1.7-1.9D色彩密度范围值 ( 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.通常在接近纯白到纯黑的范围。一台具有良好密度值的扫描仪，可以正确的

53、捕捉各种色调的层次并直接输出，如此可得到更多的影像细节。相反，一台密度值较小的扫描仪，无法检测到范围足够宽的色调层次，它将无法分辨出来影像的暗部层次，或损失亮部区域的细节，从而不能正确反映真实色彩。从而获得高品质扫描图像的另一个重要因素就是扫描仪本身的密度值指标。色彩密度范围值 ( 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.扫描仪的软件接口-TWAIN早期扫描仪厂家需要开发独立的软件来控制扫描仪，如果扫描仪的型号有变化，就需要重新写程序。为使应用软件与扫描仪之间能够直接传递资料，从而由Microtek、Adobe、Aldus（后与Adobe合并）厂家制定出一个软件工业的标准-TWAIN。使扫描仪厂家只要关心编写遵守此标准的驱动程序，而不必编写图像处理软件。图像处理软件则由专业的软件公司来完成。TWAIN的推出，大大地方便了扫描仪的应用。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.扫描稿件的类型不同的稿件需要采用不同的光源照射的方式。一般的印