标题: 可供普及沟通之低扭曲“富含讯息视讯”
Construction of Low-distorted Message-rich Videos for Pervasive Communication
作者: 游镇宇
You, Zhen-Yu
蔡文祥
Tsai, Wen-Hsiang
资讯科学与工程研究所
关键字: 富含讯息多媒体;视讯;低扭曲;资讯隐藏;普及沟通;message-rich multimedia;video;low-distorted;data hiding;pervasive communication
公开日期: 2015
摘要: 在人们的生活周遭,存于环境中许多种类的物体都可用来容纳资讯,以达到普及沟通(pervasive communication)的目的。广义上来说,这些物体皆可被视为多媒体,会以不同形式出现在生活周遭,如广告看板、海报、在萤幕上播放的视讯等等。讯息可藉由资讯隐藏的技术嵌入其中,而这些隐藏的讯息更可藉由手机、平版这些智慧型行动装置抽取出来,此种隐含讯息的多媒体即称为“富含讯息多媒体(message-rich multimedia)”。
本研究提出一新技术来制作富含讯息的视讯,与以往的讯息传递方式不同,人们可藉由“放映与再取像(display-and-imaging) ”的方式来抽取藏入的讯息,而不必透过直接传输数位档案的方式交换讯息。此外,这个新制作出的富含讯息视讯,其画质相较于先前提出的方法 [26] 有较低的扭曲。为了达到这个目的,本论文设计了讯息嵌入的程序以及一个对应的讯息抽取程序。
在讯息嵌入程序中,本研究采用了嵌入“对角位峰值讯号(diagonally-located peak values)”在视讯画面频谱中的方式,使每个视讯中的画面皆可藏入一个二位元讯号。而为解决所翻拍的视讯无法与原有影片有相同起始点的问题,以及视讯有许多不同格式的问题,本研究使用了特殊设计的起始及结束讯号及影片格式特性,让讯息嵌入程序与抽取程序间达到同步。如此一来,使用不同的行动装置以及不同的视讯格式,都能正确的将讯息嵌入以及抽取。
在讯息抽取程序中,本论文提出了一新讯号侦测的方法,设计了两个搜寻区域来侦测讯号,且使用了两个特殊门槛来决定讯号样式。接着,本论文使用了一线性资料结构,用以重现被嵌入于视讯中的讯息,此结构可使讯号更易于分析与转换,使得所提抽取程序可成功的抽取出被嵌入的讯号。最后,本论文使用视讯取样之方式,来加速讯息抽取程序,来提高所提方法的实用性。
深入的理论分析及实验结果显示该系统具有可行性及实用性。
In our lives around, many kinds of identities existing in the environment can be made use of to accommodate information for the purpose of pervasive communication. These identities may all be regarded as multimedia in a broad sense. They may appear in many forms like hard copies, advertisements, posters, displays on monitors or TVs, etc. Messages may be injected into such identities by data hiding techniques. These messages can be extracted by using mobile devices such as smart phones, tablets. Such a type of multimedia embedded with messages is called message-rich multimedia.
In this study we have proposed a new technique for creating message-rich videos, by which, differently from traditional ways of information transmission, people can exchange message without sending directly digital files such as videos and images. Furthermore, the quality of the newly-generated message-rich video is less-distorted than those proposed by a previous method [26]. Moreover, the message embedded in the video can be extracted in a display-and-imaging fashion. To achieve this purpose, a message embedding process and a corresponding message extraction process have been proposed.
For the message embedding process, the use of diagonal peak values in the frequency domain is proposed, by which the proposed message embedding method can embed a 2-bit signal in each video frame. Next, to solve the difficult issues of recording the displayed video exactly from its starting point as well as dealing with multiple video formats, the proposed embedding method makes use of specially-designed initial and ending signals as well as certain properties of the video frame rate to achieve signal synchronization in the message extraction process so that the messages can be embedded and extracted correctly using different mobile devices with different video formats and rates.
For the message extraction process, a new signal detection method has been proposed, which is based on the use of a more precise technique of setting two search regions to detect the peak values and using two thresholds to determine the signal patterns. Also, a linear structure is utilized to represent message signals by which the signals can be extracted, analyzed, and converted into ASCII codes effectively. Furthermore, a scheme based on video down-sampling has also been proposed to speed up the message extraction process effectively.
The feasibility and effectiveness of all the proposed methods have been demonstrated by theoretical analyses and good experimental results.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT070356022
http://hdl.handle.net/11536/126797
显示于类别:Thesis