Tài liệu miễn phí Kĩ thuật Viễn thông
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GSM and UMTS (P10)
This section reports about the early discussions in the 1882–1985 timeframe, the agreement on a service concept in February 1985 and the elaboration of the first set of specifications needed for tendering of infrastructure by the operators in early 1988. A well structured and future-proof portfolio of tele-, bearer and supplementary services was specified.
8/29/2018 6:10:11 PM +00:00
Xử lý hình ảnh thông minh P5
The research described in this chapter arises from the author’s work in designing and building a wearable graphics production facility used to create a new kind of visual art over the past 15 or 20 years. This work bridges the gap between computer graphics, photographic imaging, and painting with powerful yet portable electronic flashlamps. Beyond being of historical significance (the invention of the wearable computer, mediated reality, etc.), this background can lead to broader and more useful applications....
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Xử lý hình ảnh thông minh P6
In the early days of personal imaging, a specific location was selected from which a measurement space or the like was constructed. From this single vantage point, a collection of differently illuminated/exposed images was constructed using the wearable computer and associated illumination apparatus. However, this approach was often facilitated by transmitting images from a specific location (base station) back to the wearable computer, and vice versa. Thus, when the author developed the eyeglass-based computer display/camera system, it was natural to exchange viewpoints with another person (i.e., the person operating the base station)....
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Hệ thống điều khiển mờ - Thiết kế và phân tích P15
FUZZY CONTROL OF NONLINEAR TIME-DELAY SYSTEMS In this chapter, a class of nonlinear time-delay systems based on the TakagiSugeno ŽT-S. fuzzy model is defined w1x. We investigate the delay-independent stability of this model. A model-based fuzzy stabilization design utilizing the concept of parallel distributed compensation ŽPDC. is employed. The main idea of the controller design is to derive each control rule to compensate each rule of a fuzzy system.
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Cơ sở dữ liệu hình ảnh P1
DIGITAL IMAGERY Digital images have a predominant position among multimedia data types. Unlike video and audio, which are mostly used by the entertainment and news industry, images are central to a wide variety of fields ranging from art history to medicine, including astronomy, oil exploration, and weather forecasting. Digital imagery plays a valuable role in numerous human activities, such as law enforcement, agriculture and forestry management, earth science, urban planning, as well as sports, newscasting, and entertainment....
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Cơ sở dữ liệu hình ảnh P2
The emergence of multimedia, the availability of large digital archives, and the rapid growth of the World Wide Web (WWW) have recently attracted research efforts in providing tools for effective retrieval of image data based on their content (content-based image retrieval, CBIR). The relevance of CBIR for many applications, ranging from art galleries and museum archives to pictures and photographs, medical and geographic databases, criminal investigations, intellectual properties and trademarks, and fashion and interior design, make this research field one of the fastest growing in information technology. ...
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Cơ sở dữ liệu hình ảnh P3
Remote sensing is the science of measuring characteristics of interest from a distance. Our focus in this chapter is the remote sensing of Earth from instruments flown on aircraft or spacecraft. Imaging from remote sensors has had a long history, starting early in the twentieth century with photographs from balloons and aircraft. In recent years, there has been a proliferation of aerial and space-borne sensors that image the Earth at various resolutions.
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Cơ sở dữ liệu hình ảnh P4
Medical imaging has its roots in the accidental discovery of a new class of electromagnetic radiation, X rays, by Wilhelm Conrad Roentgen in 1895. The first X-ray radiograph ever taken was of his wife’s hand, revealing a picture of the living skeleton [1]. In the subsequent decades, physicians refined the art of X-ray radiography to image the structural and physiological state of internal organs such as the stomach, intestines, lungs, heart, and brain.
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Cơ sở dữ liệu hình ảnh P5
Images are central to the task of exploring for and producing oil and gas (hydrocarbons) from the Earth’s subsurface. To understand their utility, one must look at both how hydrocarbons are formed and how we explore for them. Oil and gas (hydrocarbons) are generally found in the pores of sedimentary rocks, such as sandstone or limestone. These rocks are formed by the burial of sediment over millions of years and its subsequent chemical alteration (diagenesis).
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Cơ sở dữ liệu hình ảnh P6
Rapid advances in computing and communication technologies coupled with the dramatic growth of the Internet have led to the emergence of a wide variety of multimedia applications, such as distance education, on-line virtual worlds, immersive telepresence, and scientific visualization. These applications differ from conventional distributed applications in at least two ways.
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Cơ sở dữ liệu hình ảnh P7
Advances in high-performance computing, communication, and storage technologies, as well as emerging large-scale multimedia applications, have made the design and development of multimedia information systems one of the most challenging and important directions of research and development within computer science.
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Cơ sở dữ liệu hình ảnh P8
Compression reduces the number of bits required to represent a signal. The appropriate compression strategy is a function of the type of signal to be compressed. Here, we focus on images, which can be single component (e.g., gray scale) or multiple component (e.g., three-component color or highercomponent remote sensing data). Each component can be considered to be an “image” — a two-dimensional (2D) array of pixels, and this chapter reviews the fundamentals of image compression as a 2D signal with specific statistical characteristics. ...
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Cơ sở dữ liệu hình ảnh P9
The transmission of digital imagery can impose significant demands on the resources of clients, servers, and the networks that connect them. With the explosive growth of the internet, the need for mechanisms that support rapid browsing of on-line imagery has become critical. This is particularly evident in scientific imagery.
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Cơ sở dữ liệu hình ảnh P10
Advances in modern computer and telecommunication technologies have led to huge archives of multimedia data in diverse application areas such as medicine, remote sensing, entertainment, education, and on-line information services. This is similar to the rapid increase in the amount of alphanumeric data during the early days of computing, which led to the development of database management systems (DBMS).
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Cơ sở dữ liệu hình ảnh P11
Recent progress in multimedia database systems has resulted in solutions for integrating and managing a variety of multimedia formats that include images, video, audio, and text [1]. Advances in automatic feature extraction and image-content analysis have enabled the development of new functionalities for searching, filtering, and accessing images based on perceptual features such as color [2,3], texture [4,5], shape [6], and spatial composition [7].
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Cơ sở dữ liệu hình ảnh P12
Pictures of water, grass, a bed of flowers, or a pattern on a fabric contain strong examples of image texture. Many natural and man-made objects are distinguished by their texture. Brodatz [1], in his introduction to Textures: A photographic album, states “The age of photography is likely to be an age of texture.
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Cơ sở dữ liệu hình ảnh P13
The human–machine interface is evolving at an incredible pace, surpassing the traditional text-based boundaries. A driving force motivating this development is the need to endow computers with capabilities that parallel our perceptual abilities. Vision is arguably our most significant sense, giving rise to efforts to empower computers to represent, process, understand, and act on visual imagery. As a result, images are being generated at a mind-boggling pace from a variety of sources.
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Cơ sở dữ liệu hình ảnh P14
Indexing plays a fundamental role in supporting efficient retrieval of sequences of images, of individual images, and of selected subimages from multimedia repositories. Three categories of information are extracted and indexed in image databases: metadata, objects and features, and relations between objects [1]. This chapter is devoted to indexing structures for objects and features.
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Cơ sở dữ liệu hình ảnh P15
In this chapter we focus on the design of methods for rapidly searching a database of multimedia objects, allowing us to locate objects that match a query object, exactly or approximately. We want a method that is general and that can handle any type of multimedia objects.
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Cơ sở dữ liệu hình ảnh P16
The explosive growth of multimedia data, both on the Internet and in domainspecific applications, has produced a pressing need for techniques that support efficient storage, transmission, and retrieval of such information. Indexing (Chapters 7, 14, and 15) and compression (Chapter 8) are complementary methods that facilitate storage, search, retrieval and transmission of imagery, and other multimedia data types.
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Xử lý hình ảnh thông minh P1
Personal imaging is an integrated personal technologies, personal communicators, and mobile multimedia methodology. In particular, personal imaging devices are characterized by an “always ready” usage model, and comprise a device or devices that are typically carried or worn so that they are always with us [1]. An important theoretical development in the field of personal imaging is that of humanistic intelligence (HI).
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Xử lý hình ảnh thông minh P2
This chapter considers the question of where to place the sensory and display apparatus on the body. Although the final conclusion is that both should be placed, effectively, right within the eye itself, various other possibilities are considered and explained first. In terms of the various desirable properties the apparatus should be:
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Xử lý hình ảnh thông minh P3
This chapter discloses the operational principles of the EyeTap reality mediator, both in its idealized form and as practical embodiments of the invention. The inner workings of the reality mediator, in particular, its optical arrangement, are described.
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Xử lý hình ảnh thông minh P4
The EyeTap glasses of the previous chapter absorb and quantify rays of light, process these rays of light, and then resynthesize corresponding rays of light. Each synthesized ray of light is collinear with, and responsive to, a corresponding absorbed ray of light. The exact manner in which it is responsive is the subject of this chapter. In other words, this chapter provides meaning to the word “quantify” in the phrase “absorb and quantify.
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Nguyên tắc cơ bản của lượng tử ánh sáng P15
Electronics is the technology of controlling the flow of electrons whereas photonics is the technology of controlling the flow of photons. Electronics and photonics have been
8/29/2018 6:09:52 PM +00:00
Nguyên tắc cơ bản của lượng tử ánh sáng P16
Light can be emitted from a semiconductor material as a result of electron-hole recombination. However, materials capable of emitting such light do not glow at room
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Nguyên tắc cơ bản của lượng tử ánh sáng P17
Simkon Poisson (1781-1840) developed the probability distribution that describes photodetector noise. A photodetector is a device that measures photon flux or optical power by converting the energy of the absorbed photons into a measurable form.
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Nguyên tắc cơ bản của lượng tử ánh sáng P18
Certain materials change their optical properties when subjected to an electric field. This is caused by forces that distort the positions, orientations, or shapes of the molecules constituting the material. The electro-optic effect is the
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Nguyên tắc cơ bản của lượng tử ánh sáng P19
THEORY OF FOUR-WAVE MIXING NONLINEAR MEDIA DISPERSIVE NONLINEAR MEDIA OPTICAL SOLITONS Nicolaas Bloembergen (born 1920) has carried out pioneering studies in nonlinbar optics since the early 1960s. He shared the 1981 Nobel Prize with Arthur Schawlow. 737 Throughout the long history of optics, and
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Nguyên tắc cơ bản của lượng tử ánh sáng P20
The refractive index of an optical medium is altered by the presence of sound. Sound therefore modifies the effect of the medium on light; i.e., sound can contro2 light (Fig. 20.0-l). Many useful devices make use of this acousto-optic
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