Reading 专业英语阅读

A Review of Fragile Image Watermarks(水印)

editing also facilitates unauthorized use, misappropriation（占有）, and misrepresentation（误传）. Content providers are naturally concerned about these issues and watermarking, which is the act of embedding another signal (the watermark) into an image, have been proposed to

signal processing techniques. The process of embedding the watermark requires modifying the original image and in essence the watermarking process inserts a controlled amount of “distortion”（失真）in the image.

image.

human visual system to minimize the perceptual（知觉的）distortion in the watermarked image. In the class of transparent watermarks one may further categorize techniques as robust or fragile. A robust mark is designed to resist attacks that attempt to remove or destroy the mark. Such attacks include lossy compression, filtering, and geometric scaling(缩放). A fragile mark is designed to detect slight changes to the watermarked image with high probability. The main application of fragile watermarks is in content authentication. Most of the work, as reported in the literature, in watermarking is in the area of robust techniques. Many important applications could benefit from the use of fragile watermarks.

A fragile watermark is a mark that is readily altered or destroyed when the host image is modified through a linear or nonlinear

transformation. Fragile marks are not suited for enforcing copyright ownership of digital images; an attacker would attempt to destroy the embedded mark and fragile marks are, by definition, easily destroyed. The sensitivity of fragile marks to modification leads to their use in image authentication. That is, it may be of interest for parties to verify that an image has not been edited, damaged, or altered since it was marked.

Image

questioned. Common examples are the marking of images in a database to detect tampering, the use in a “trustworthy camera” so news agencies can ensure an image is not fabricated or edited to falsify events, and the marking of images in commerce so a buyer can be assured that the images bought are authentic upon receipt. Other situations include images used in courtroom evidence, journalistic photography, or images involved in espionage.

Another method to verify the authenticity of a digital work is the use of a signature system. In a signature system, a digest of the data to be authenticated is obtained by the use of cryptographic（密码的）hash functions. The digest is then cryptographically signed to produce the

While the purpose of fragile watermarking and digital signature systems are similar, watermarking systems offer several advantages compared to signature systems at the expense of requiring some modification (watermark insertion) of the image data. Since a watermark is embedded directly in the image data, no additional information is necessary for authenticity verification. (This is unlike digital signatures since the

signature itself must be bound to the transmitted data.) Therefore the critical information needed in the authenticity testing process is discreetly hidden and more difficult to remove than a digital signature. Also, digital signature systems view an image as an arbitrary bit stream and do not exploit its unique structure. Therefore a signature system may be able to detect that an image had been modified but cannot characterize the alterations. Many watermarking systems can determine which areas of a marked image have been altered and which areas have not, as well as estimate the nature of the alterations.

Translation:

1.数字多媒体时代的到来使得图像内容更容易被创造和发送，

然而由于图像易于拷贝、编辑，因此也使其更易被非法使用、占有及误传。

2.多种水印已被开发并被广泛使用。水印分为可视和不可视，

可视水印很容易观察到，而不可视水印是透明的，只有通过信号处理技术才能识别出来。

3.不可视水印利用了人体的视觉系统的特性，把嵌入水印的图

像的知觉失真降至最小。

4.由于数字图像易于修改，因此当图像的可靠性受到质疑时，

可使用安全的认证系统来检验图像是否已被篡改。

5.之后，接收者通过检验数据的（可能已被修改的）摘要来验

证签名，使用验证算法可以确定数据是否可信。Questions:

1.What action can be taken to prevent the unauthorized use,

misappropriation, and misrepresentation of image content?

2.What are robust watermarks designed for?

3.Are fragile watermarks suitable for image authentication? Why?

4.In which fields are image authentication used?

5.What are the advantages of fragile watermarking over the digital

signature system in verifying the authenticity of a digital work? Question answering:

1.watermarks

2.to resist attacks that attempt to remove or destroy the mark

3.yes, because they are sensitive to modification

https://www.360docs.net/doc/b613160793.html,w, commerce, defense and journalism

5.no additional information is necessary; can determine which areas

of a marked image have been altered and which areas have not, as well as estimate the nature of alterations

abstract:

This paper introduces the robust and fragile watermark with emphasis on the latter. It also covers the application of the fragile watermark in image authentication systems. This paper concludes with a comparison of the signature system with fragile watermarking.

PartⅡAbstract Translation (15 points)

Directions: Translate the following abstract.

概率论与数理统计课程教学研究

XXX

（西安电子科技大学计算机学院，陕西西安710071）

摘要：概率论与数理统计作为理工科学生的一门重要专业基础课程，在其后续课程学习及实际工作中起着非常重要的作用。针对目前课程教学的现状

及存在的问题，本文从激发学习兴趣、注重实际应用、实施多样化教学

和培养实践能力等方面探讨了如何有效提高概率论与数理统计课程教

学的质量。通过教学实践，证明了新的教学方法取得了较好的效果。词汇

概率论Probability

数理统计Mathematical Statistics

Teaching of Probability and Mathematical Statistics

XXX

(School of Computer Science and Technology,

Xidian University, Xi’an, Shaanxi, 710071)

Abstract An important specialized core course for students of science and engineering, probability and mathematical statistics serves as the foundation for subsequent study and work. This paper, aimed at the existing teaching problems, explores an effective way to improve the teaching quality from four aspects: arousing interest, emphasizing practice, employing diversified methods, and cultivating ability. The application of the proposed teaching method shows that it is effective in improving the teaching quality.

Part ⅣReading Comprehension and Translation (20 points) Directions: Read the article below, and SELECT the best answer to each question (10 points), and TRANSLATE the underlined sentences (10 points).

Charge of the LED Brigade

1FOR an object whose image represents a bright idea the incandescent light bulb(白炽灯) is increasingly being recognized as a bad one. [1] After a century as a primary source of artificial light these energy-guzzling bulbs are set to be replaced by

switch will happen fast for a part of the electrical industry that has relied on a single technology for 100 years.

2LEDs are already widely used as the backlights for mobile phones, computer monitors and televisions. A recent report by McKinsey(麦肯锡), a consultancy, reckons that by 2020 LEDs could make up 59% by value of the total lighting market compared with 10% in 2010.

3

uarters of that will go on “general lighting” for homes, the biggest part of the market, and on work and outdoor illumination such as streetlamps.

4The change is being driven by regulations, technical improvements and fickle consumers. Nearly half the wo rld’s light sockets (灯座) have an incandescent bulb, according to Philip Smallwood of IMS Research. [3] Conventional bulbs have

of shedding light. Yet lighting consumes 25% of the world’s el ectricity and wasteful

the EU are close to phasing them out; other countries are set to do so too.

5 For efficiency, compact fluorescent lamps(荧光灯) are an admirable replacement for regular light bulbs. But for home lighting they have failed to sparkle. Consumers dislike the “cold” light they give off and their poor lifespan. The small amounts of poisonous mercury they contain are also in the sights of many lawmakers.[4] LEDs, on the other hand, use a fifth of the electricity of a comparable incandescent bulb and

6[5]

But prices are falling rapidly. According to America’s Department of Energy new production technology should see costs tumble. In ten years’ time LEDs will cost a tenth of the current price.

7For the world’s “big three” light bu lb-makers—Philips, Osram, an arm of Germany’s Siemens, and GE Lighting have around 60% of the global market—this represents something of a dilemma. Although LEDs will be more profitable than incandescent bulbs the replacement market will eventually dwindle. The bulbmakers hope that consumers will change their lights as new and better ones come along, not because the old one is broken.

8 They should not be too gloomy: the immediate future is bright. McKinsey predicts that the global lighting market, worth €69 billion in 2010, will grow by around 60% in a decade (not least because of the relatively high price of LEDs). As Mr Smallwood points out, more light and increasing wealth go hand in hand. The average American home has 42 light sockets compared with about 15 in China. And LEDs will be used both for new lighting and to replace old fixtures too.

9Yet despite having the capital, patents and know-how the big three are set to face hot competition from firms for which LEDs are already part of their business. Asian consumer-electronics giants such as Samsung, LG, Toshiba, Panasonic and Sharp are gearing up to produce LED lights. And they may have an advantage when growing demand for essential raw materials stretches supply chains. Asia is the world’s biggest and fastest-growing lighting market, so companies based there will be well placed to flick the switch on LEDs.

1 According to the article, which is the main reason for the incandescent light bulbs being replaced by the LEDs?

A The incandescent light bulb is more expensive.

B The LEDs are widely used as the backlights.

C The incandescent light bulb is less convenient.

D The LEDs consume less energy than the incandescent light bulbs.

2 According to the article, which of the following is NOT the driving force for the switch from the incandescent light bulbs to the LEDs?

A Technical improvement

B Agreement

C Regulation

D Consumers who keep changing their mind

3 What does the phrase “phase out” in the last line of Paragraph

4 mean?

A Continue to use

B Force to go away

C Understand

D Stop using gradually

4 According to the article, some people dislike to use the fluorescent lamps for home lighting. Which of the following is NOT the reason for that?

A T he “cold” light

B The small amounts of poisonous mercury they contain

C The higher efficiency

D The poor lifespan

5 According to the article, compared with the “big-three”, what advantage do the Asian consumer-electronic companies have in the lighting market?

A Capital

B Location

C Advanced technology

D High-quality labor force

DBDCB

(1) 在过去的一个世纪中，白炽灯泡一直为人造灯源的基本产品；但现在，耗能惊人的白炽灯泡注定将被由半导体驱动的发光二极管（LED）所替代。灯泡作为电气行业的一部分，在过去的百年间长期依赖于单一技术，因此，灯源的转化会很快到来。

(2) 其产业利润将达到一千一百亿欧元（一千六百亿美元），大约相当于全球电视机销售价值的总和。

(3) 由于价格便宜，安装便捷，照射效果好，传统灯泡在一百年间几乎没有什么改进。但一方面，照明耗费了全球电力供应的四分之一；另一方面，白炽灯作为有效灯源的同时，也释放出大量热量。美国，日本和欧盟诸国已着手计划将白炽灯逐步淘汰。其它各国也将效仿此法。

(4) 另一方面，LED灯的耗电量仅为白炽灯的五分之一，但使用寿命却是白炽灯泡的20-50倍。

(5) 当下的阻碍是价格因素。新型60瓦LED灯泡售价为四十多美元，而普通灯泡的价格仅为一美元左右。