Lesson 29 Compression s电子技术专业英语教程.ppt

1、Unit10 Digital Multimedia Systems,Lesson 29 Compression Methods.ppt 电子技术专业英语教程冯新宇 主编 电子工业出版社 ,2020/10/11,电子技术专业英语教程,2,Unit29 Digital Multimedia Systems,Backgrounds Text tour Language in use Vocabulary Structure Reading/writing techniques,2020/10/11,电子技术专业英语教程,3,Terminology pixeln.【计】像素 waveletn.小波 s

2、ubsampling二次抽样 single frame单帧；一幅画面 laser disc激光影碟，雷射影碟 chrominancen.色品，彩色信号，色度；【计】 色度 Luminancen.亮度；【计】 亮度 interpolationn.插入值，内插；插值法，内插法 rastern.光栅；【电】 试映图； pattern recognition模式识别 discrete cosine transform（DCT）离散余弦变换,Backgrounds,2020/10/11,电子技术专业英语教程,4,Terminology vector quantization矢量量化 CDTV（conve

3、ntional definition television）普通清晰度电视 bilevel image二值图像，黑白图像 facsimile transmission传真发送 entropy coding熵编码 lossy compression有损压缩 ADPCM自适应音频脉冲编码,Backgrounds,2020/10/11,电子技术专业英语教程,5,Terminology motion compensation 动态补偿，运动补偿 neural network神经网络 fast Fourier transform 快速傅里叶变换 DVI交互式数字视频系统 CD-I交互式CD hybrid

4、 coding混合编码法,Backgrounds,2020/10/11,电子技术专业英语教程,6,Text tour,Outline - Introduction - Taxonomy of compression approaches Lossy compression Prediction Frequency-oriented compression Importance-oriented compression Hybrid coding,2020/10/11,电子技术专业英语教程,7,Introduction,Compression is essential if audio, ima

5、ges, and video are to be used in digital multimedia applications. A megabyte of space would be filled by roughly six seconds of CD-quality audio, a single 640480-pixel color image stored using 24 bits per pixel, or a single frame - 1/30 second-of CIF video. Nevertheless, videodisc applications often

6、 have more than 20 minutes of video, perhaps 10 000 slides, and 30 minutes of stereo sound on each laser disc side. And with the tremendous volume of data that will be received each day from planned NASA missions and other scientific ventures, the need for proven compression techniques is obvious.,2

7、020/10/11,电子技术专业英语教程,8,Compression of digital data involves computational algorithms that can be implemented in software. Some involve digital versions of signal processing methods, others involve pattern recognition, and still others use statistics or characteristics of particular data types or sam

8、ples. High-speed implementations involve VLSI chips, such as for audio digital signal processing, discrete cosine transform, or vector quantization approaches.,2020/10/11,电子技术专业英语教程,9,Taxonomy of compression approaches,Figure 35-1 Selected compression approaches,2020/10/11,电子技术专业英语教程,10,Lossy compre

9、ssion,Lossy or noisy compression may add artifacts that can be perceived. Careful study of the human visual system has focused attention on approaches that cause little perceived loss in quality, but achieve high compression ratios.,2020/10/11,电子技术专业英语教程,11,Prediction,Predictive approaches like ADPC

10、M involve predicting subsequent values by observing previous ones, and transmitting only the usually small differences between actual and predicted data. An example involves motion compensation. Successive frames in a video sequence are often quite similar or have blocks of pixels shifted from one f

11、rame to the next - for example, as the camera pans or a person moves. Although it is computationally expensive to analyze images and yield motion vectors, parallel computers or neural networks can help with the processing.,2020/10/11,电子技术专业英语教程,12,Frequency-oriented compression,Subband coding can ex

12、ploit the fact that humans have different sensitivities to various spatial and temporal frequency combinations. The idea is to separate (for example, using a series of filters) the different frequency combinations, and then to code with greater fidelity the frequencies that humans pay particular att

13、ention to. Without subband coding, all frequency combinations would be coded identically, so the technique achieves high perceived quality with fewer total bits.,2020/10/11,电子技术专业英语教程,13,Importance-oriented compression,Other characteristics of images besides frequency are used as the basis for compr

14、ession. The principle is to consider as more important those parts of an image that humans are better attuned to. An example of this approach is to filter images, getting rid of details that cannot be perceived, as in the low-pass filtering done for real-time video with DVI systems. Another techniqu

15、e is to allocate more bits to encode important parts of an image, such as where edges occur, than to encode large homogeneous regions, such as those depicting clouds.,2020/10/11,电子技术专业英语教程,14,Hybrid coding,Various compression approaches can be combined, for example, DCT and differential pulse code m

16、odulation, subband coding and DCT, or differential pulse code modulation and vector quantization. Generally, subband coding is coupled with vector quantization. Systems and standards for video compression often apply motion compensation for temporal compression, transform coding for spatial compress

17、ion, and Huffman or arithmetic coding for statistical compression.,2020/10/11,电子技术专业英语教程,15,Vocabulary fractal taxonomy palette diagonal Structure Reading/writing techniques,Language in use,2020/10/11,电子技术专业英语教程,16,Vocabulary,2020/10/11,电子技术专业英语教程,17,fractal in dictionary,RSC Problem of Fractal Dime

18、nsion calculation of Actual Fractal 实际分形体维数计算中的RSC问题 Fractal Graphics Based on MFC 基于MFC的分形图形实现方法 Dla simulation of fractal flocs and calculation of fractional dimemsion. 絮凝体的DLA分形模拟及其分形维数的计算方法 FRACTAL INTERPOLATION BASED ON FBM 基于FBM的分形插值方法 Fibonacci Process and DLA Fractal Fibonacci过程和DLA分形,2020/1

19、0/11,电子技术专业英语教程,18,fractal in dictionary,Fractal Dimension Estimation of Signal Based on Fractal Brownian Motion Model 基于分形布朗运动模型信号分维数估计 The Fractal BET Model of Adsorption 分形BET吸附模型 Fractal Classification of fold Complex degree 褶皱复杂程度的分形分类 Golden self?similarity and fractal proportion 黄金自相似性与分形比 FB

20、MBASED FRACTAL SIMULATION OF TERRAIN 基于FBM的分形地形模拟原理研究,2020/10/11,电子技术专业英语教程,19,fractal in text,Fractals (images that can be described by a set of rules specified with a relatively small number of bits) allow compression of natural scenes where the underlying structure matches this type of model. 用底层

21、结构匹配典型的模式，分形（用相对较少的比特率通过一套指定的规则来描述的影像）允许自然景象的压缩。,2020/10/11,电子技术专业英语教程,20,taxonomy in dictionary,Number taxonomy is an identifier taxonomy. 号分类学是一个标识符分类法。 Organizations that choose to make a particular taxonomy available for categorization or identification can register a taxonomy and use that taxon

22、omy as unchecked. 商业实体如果需要使用一个特别的类别或标识分类法的话，他可以注册一个分类法并以未检验分类法的形式使用。 extinct group of armored fishlike vertebrates; taxonomy is not clear. 已灭绝的有甲脊椎动物，外形与鱼相似；其分类尚不明确。 extinct group of armored jawless vertebrates; taxonomy is not clear. 一种已灭绝的无下巴甲壳脊椎动物；其分类尚不明确。 Of course, real?life blonds dont fit nea

23、tly into this taxonomy. 当然现实生活中女人的金发很难完全符合这些类型。,2020/10/11,电子技术专业英语教程,21,taxonomy in dictionary,Number taxonomy is an identifier taxonomy. The following list of values are defined in the UDDI:types taxonomy. 下面列表中的值都是在uddi类别分类法中定义的。 extinct group of armored jawless fishes or fishlike vertebrate; tax

24、onomy is not clear. 现已灭绝的无颚有甲鱼类或鱼状脊椎动物；其分类尚不明确。 These tradeoffs can be examined by organizing the various approaches into a taxonomy (classification). 这些折衷可以通过把不同的方法组织成一个类别加以检查。 Externalization is capturing knowledge in an external repository and organizing it according to classification framework o

25、r taxonomy. 外部化是从外部的仓库里获取知识，并按照分类的基本框架或分类学将知识组织起来。 tModel: The UDDI type taxonomy is structured to allow for categorization of registry entries other than tModels. tmodel:uddi类别分类法是结构化的，允许对tmodel外的注册信息条目进行分类。,2020/10/11,电子技术专业英语教程,22,taxonomy in text,Figure 35-1 shows a taxonomy of compression appro

26、aches. 图35-1显示了压缩方法分类。,2020/10/11,电子技术专业英语教程,23,palette in dictionary,painting that applies the pigment thickly so that brush or palette knife marks are visible. 一种绘画方法，涂抹厚厚的颜料以便于画笔或者雕刻刀能刻上有形的痕迹。 Developer can install ole control onto the palette or choose from among the ole control include in delph

27、i 2.0. 开发者们可以把ole控制安装到调色板上或从包括在delphi2。0中的ole控制中选择。 Data may include full objects such as an entire .gif file, or a partial object such as a color palette of a .gif file. 数据可以是全对象，如整个.gif文件，或部分对象，如.gif文件的调色板。,2020/10/11,电子技术专业英语教程,24,palette in dictionary,The H. J. Heinz Co., which has sold the cond

28、iment in red, green, purple, pink and orange, is adding blue to its palette. 亨氏食品公司已经推出了红色、紫色、粉红和橙色的调味酱，而现在，他们的调色盘中又增添了一笔：蓝色。 Major events such as the Swiss Alpine Marathon,Nordic Cross?Country World Championships,Spengler Cup Ice Hockey Tournament and the UBS Snowboard World Championships are just a few of the highlights from an impressive palette of sporting attractions. 重要赛事如，瑞士高山马拉松、北欧越野滑雪世界锦标赛、施彭格勒杯冰球联赛以及ubs滑雪板运动世界锦标赛，这些只是众多吸引人的体育运动中精彩的一部分。,2020/10/11,电子技术专业英语教程,25,palette in text,Color spaces often cover a palette of size 224, which means 24 bits are needed. 色彩空间通常涵盖了一个大小为224