Digital Signals
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Discrete Cosine Transform Based Image Fusion Techniques VPS Naidu MSDF Lab, FMCD, National Aerospace Laboratories, Bangalore, INDIA E.Mail: [email protected]
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by NAL-IR Journal of Communication, Navigation and Signal Processing (January 2012) Vol. 1, No. 1, pp. 35-45 Discrete Cosine Transform based Image Fusion Techniques VPS Naidu MSDF Lab, FMCD, National Aerospace Laboratories, Bangalore, INDIA E.mail: [email protected] Abstract: Six different types of image fusion algorithms based on 1 discrete cosine transform (DCT) were developed and their , k 1 0 performance was evaluated. Fusion performance is not good while N Where (k ) 1 and using the algorithms with block size less than 8x8 and also the block 1 2 size equivalent to the image size itself. DCTe and DCTmx based , 1 k 1 N 1 1 image fusion algorithms performed well. These algorithms are very N 1 simple and might be suitable for real time applications. 1 , k 0 Keywords: DCT, Contrast measure, Image fusion 2 N 2 (k 1 ) I. INTRODUCTION 2 , 1 k 2 N 2 1 Off late, different image fusion algorithms have been developed N 2 to merge the multiple images into a single image that contain all useful information. Pixel averaging of the source images k 1 & k 2 discrete frequency variables (n1 , n 2 ) pixel index (the images to be fused) is the simplest image fusion technique and it often produces undesirable side effects in the fused image Similarly, the 2D inverse discrete cosine transform is defined including reduced contrast. To overcome this side effects many as: researchers have developed multi resolution [1-3], multi scale [4,5] and statistical signal processing [6,7] based image fusion x(n1 , n 2 ) (k 1 ) (k 2 ) N 1 N 1 techniques. -
How I Came up with the Discrete Cosine Transform Nasir Ahmed Electrical and Computer Engineering Department, University of New Mexico, Albuquerque, New Mexico 87131
mxT*L. BImL4L. PRocEsSlNG 1,4-5 (1991) How I Came Up with the Discrete Cosine Transform Nasir Ahmed Electrical and Computer Engineering Department, University of New Mexico, Albuquerque, New Mexico 87131 During the late sixties and early seventies, there to study a “cosine transform” using Chebyshev poly- was a great deal of research activity related to digital nomials of the form orthogonal transforms and their use for image data compression. As such, there were a large number of T,(m) = (l/N)‘/“, m = 1, 2, . , N transforms being introduced with claims of better per- formance relative to others transforms. Such compari- em- lh) h = 1 2 N T,(m) = (2/N)‘%os 2N t ,...) . sons were typically made on a qualitative basis, by viewing a set of “standard” images that had been sub- jected to data compression using transform coding The motivation for looking into such “cosine func- techniques. At the same time, a number of researchers tions” was that they closely resembled KLT basis were doing some excellent work on making compari- functions for a range of values of the correlation coef- sons on a quantitative basis. In particular, researchers ficient p (in the covariance matrix). Further, this at the University of Southern California’s Image Pro- range of values for p was relevant to image data per- cessing Institute (Bill Pratt, Harry Andrews, Ali Ha- taining to a variety of applications. bibi, and others) and the University of California at Much to my disappointment, NSF did not fund the Los Angeles (Judea Pearl) played a key role. -
Reception Performance Improvement of AM/FM Tuner by Digital Signal Processing Technology
Reception performance improvement of AM/FM tuner by digital signal processing technology Akira Hatakeyama Osamu Keishima Kiyotaka Nakagawa Yoshiaki Inoue Takehiro Sakai Hirokazu Matsunaga Abstract With developments in digital technology, CDs, MDs, DVDs, HDDs and digital media have become the mainstream of car AV products. In terms of broadcasting media, various types of digital broadcasting have begun in countries all over the world. Thus, there is a demand for smaller and thinner products, in order to enhance radio performance and to achieve consolidation with the above-mentioned digital media in limited space. Due to these circumstances, we are attaining such performance enhancement through digital signal processing for AM/FM IF and beyond, and both tuner miniaturization and lighter products have been realized. The digital signal processing tuner which we will introduce was developed with Freescale Semiconductor, Inc. for the 2005 line model. In this paper, we explain regarding the function outline, characteristics, and main tech- nology involved. 22 Reception performance improvement of AM/FM tuner by digital signal processing technology Introduction1. Introduction from IF signals, interference and noise prevention perfor- 1 mance have surpassed those of analog systems. In recent years, CDs, MDs, DVDs, and digital media have become the mainstream in the car AV market. 2.2 Goals of digitalization In terms of broadcast media, with terrestrial digital The following items were the goals in the develop- TV and audio broadcasting, and satellite broadcasting ment of this digital processing platform for radio: having begun in Japan, while overseas DAB (digital audio ①Improvements in performance (differentiation with broadcasting) is used mainly in Europe and SDARS (satel- other companies through software algorithms) lite digital audio radio service) and IBOC (in band on ・Reduction in noise (improvements in AM/FM noise channel) are used in the United States, digital broadcast- reduction performance, and FM multi-pass perfor- ing is expected to increase in the future. -
Next-Generation Photonic Transport Network Using Digital Signal Processing
Next-Generation Photonic Transport Network Using Digital Signal Processing Yasuhiko Aoki Hisao Nakashima Shoichiro Oda Paparao Palacharla Coherent optical-fiber transmission technology using digital signal processing is being actively researched and developed for use in transmitting high-speed signals of the 100-Gb/s class over long distances. It is expected that network capacity can be further expanded by operating a flexible photonic network having high spectral efficiency achieved by applying an optimal modulation format and signal processing algorithm depending on the transmission distance and required bit rate between transmit and receive nodes. A system that uses such adaptive modulation technology should be able to assign in real time a transmission path between a transmitter and receiver. Furthermore, in the research and development stage, optical transmission characteristics for each modulation format and signal processing algorithm to be used by the system should be evaluated under emulated quasi-field conditions. We first discuss how the use of transmitters and receivers supporting multiple modulation formats can affect network capacity. We then introduce an evaluation platform consisting of a coherent receiver based on a field programmable gate array (FPGA) and polarization mode dispersion/polarization dependent loss (PMD/PDL) emulators with a recirculating-loop experimental system. Finally, we report the results of using this platform to evaluate the transmission characteristics of 112-Gb/s dual-polarization, quadrature phase shift keying (DP-QPSK) signals by emulating the factors that degrade signal transmission in a real environment. 1. Introduction amplifiers—which is becoming a limiting factor In the field of optical communications in system capacity—can be efficiently used. -
Chapter 1 Computers and Digital Basics Computer Concepts 2014 1 Your Assignment…
Chapter 1 Computers and Digital Basics Computer Concepts 2014 1 Your assignment… Prepare an answer for your assigned question. Use Chapter 1 in the book and this PowerPoint to procure information. Prepare a PowerPoint presentation to: 1. Show your answer and additional information/facts – make sure you understand and can explain your answer. Provide as must information and detail as possible. Add graphics to enhance. 2. Where in the book did you find your information? Include the page number. 3. What more do you need to find out to help you better understand this question? Be prepared to share your information with the class. Chapter 1: Computers and Digital Basics 2 1 The Digital Revolution The digital revolution is an ongoing process of social, political, and economic change brought about by digital technology, such as computers and the Internet The technology driving the digital revolution is based on digital electronics and the idea that electrical signals can represent data, such as numbers, words, pictures, and music Chapter 1: Computers and Digital Basics 6 1 The Digital Revolution Digitization is the process of converting text, numbers, sound, photos, and video into data that can be processed by digital devices The digital revolution has evolved through four phases, beginning with big, expensive, standalone computers, and progressing to today’s digital world in which small, inexpensive digital devices are everywhere Chapter 1: Computers and Digital Basics 7 1 The Digital Revolution Chapter 1: Computers and Digital Basics -
Digital Signal Processing: Theory and Practice, Hardware and Software
AC 2009-959: DIGITAL SIGNAL PROCESSING: THEORY AND PRACTICE, HARDWARE AND SOFTWARE Wei PAN, Idaho State University Wei Pan is Assistant Professor and Director of VLSI Laboratory, Electrical Engineering Department, Idaho State University. She has several years of industrial experience including Siemens (project engineering/management.) Dr. Pan is an active member of ASEE and IEEE and serves on the membership committee of the IEEE Education Society. S. Hossein Mousavinezhad, Idaho State University S. Hossein Mousavinezhad is Professor and Chair, Electrical Engineering Department, Idaho State University. Dr. Mousavinezhad is active in ASEE and IEEE and is an ABET program evaluator. Hossein is the founding general chair of the IEEE International Conferences on Electro Information Technology. Kenyon Hart, Idaho State University Kenyon Hart is Specialist Engineer and Associate Lecturer, Electrical Engineering Department, Idaho State University, Pocatello, Idaho. Page 14.491.1 Page © American Society for Engineering Education, 2009 Digital Signal Processing, Theory/Practice, HW/SW Abstract Digital Signal Processing (DSP) is a course offered by many Electrical and Computer Engineering (ECE) programs. In our school we offer a senior-level, first-year graduate course with both lecture and laboratory sections. Our experience has shown that some students consider the subject matter to be too theoretical, relying heavily on mathematical concepts and abstraction. There are several visible applications of DSP including: cellular communication systems, digital image processing and biomedical signal processing. Authors have incorporated many examples utilizing software packages including MATLAB/MATHCAD in the course and also used classroom demonstrations to help students visualize some difficult (but important) concepts such as digital filters and their design, various signal transformations, convolution, difference equations modeling, signals/systems classifications and power spectral estimation as well as optimal filters. -
Lecture Notes for Digital Electronics
Lecture Notes for Digital Electronics Raymond E. Frey Physics Department University of Oregon Eugene, OR 97403, USA [email protected] March, 2000 1 Basic Digital Concepts By converting continuous analog signals into a finite number of discrete states, a process called digitization, then to the extent that the states are sufficiently well separated so that noise does create errors, the resulting digital signals allow the following (slightly idealized): • storage over arbitrary periods of time • flawless retrieval and reproduction of the stored information • flawless transmission of the information Some information is intrinsically digital, so it is natural to process and manipulate it using purely digital techniques. Examples are numbers and words. The drawback to digitization is that a single analog signal (e.g. a voltage which is a function of time, like a stereo signal) needs many discrete states, or bits, in order to give a satisfactory reproduction. For example, it requires a minimum of 10 bits to determine a voltage at any given time to an accuracy of ≈ 0:1%. For transmission, one now requires 10 lines instead of the one original analog line. The explosion in digital techniques and technology has been made possible by the incred- ible increase in the density of digital circuitry, its robust performance, its relatively low cost, and its speed. The requirement of using many bits in reproduction is no longer an issue: The more the better. This circuitry is based upon the transistor, which can be operated as a switch with two states. Hence, the digital information is intrinsically binary. So in practice, the terms digital and binary are used interchangeably. -
Lecture 9 Analog and Digital I/Q Modulation
Lecture 9 Analog and Digital I/Q Modulation Analog I/Q Modulation • Time Domain View •Polar View • Frequency Domain View Digital I/Q Modulation • Phase Shift Keying • Constellations 11/4/2006 Coherent Detection Transmitter Output 0 x(t) y(t) π 2cos(2 fot) Receiver Output Lowpass y(t) z(t) r(t) π 2cos(2 fot) • Requires receiver local oscillator to be accurately aligned in phase and frequency to carrier sine wave 11/4/2006 L Lecture 9 Fall 2006 2 Impact of Phase Misalignment in Receiver Local Oscillator Transmitter Output 0 x(t) y(t) π 2cos(2 fot) Receiver Output Output is zero Lowpass y(t) z(t) r(t) π 2sin(2 fot) • Worst case is when receiver LO and carrier frequency are phase shifted 90 degrees with respect to each other 11/4/2006 L Lecture 9 Fall 2006 3 Analog I/Q Modulation Baseband Input iti(t)(t) it (t) t cos 2 f tπ yt (t) 2cos(2( π 0 )f1t) π 2sin(2sin() 2π f0t f1t) qqt(t)(t) t qt (t) • Analog signals take on a continuous range of values (as viewed in the time domain) • I/Q signals are orthogonal and therefore can be transmitted simultaneously and fully recovered 11/4/2006 L Lecture 9 Fall 2006 4 Polar View of Analog I/Q Modulation it (t) = i(t)cos() 2π fot + 0° ii(t(t)t) it (t) qt (t) = q(t)cos() 2π fot + 90° = q(t)sin() 2π fot t cos 2π f tπ y (t) 2cos(2( 0 )f1t) t 2 2 π 2sin(2sin() 2π f0t f1t) yt (t) = i (t) + q (t) cos() 2π fot + θ(t) qq(tt(t)) −1 where θ(t) = tan q(t)/i(t) t qt (t) −180°<θ < 180° 11/4/2006 L Lecture 9 Fall 2006 5 Polar View of Analog I/Q Modulation (Con’t) • Polar View shows amplitude and phase of it(t), qt(t) and yt(t) combined signal for transmission at a given frequency f. -
Introduction (Pdf)
chapter1.fm Page 1 Thursday, August 17, 2000 4:43 PM CHAPTER 1 INTRODUCTION The evolution of digital circuit design n Compelling issues in digital circuit design n How to measure the quality of digital design n Valuable references 1.1 A Historical Perspective 1.2 Issues in Digital Integrated Circuit Design 1.3 Quality Metrics of A Digital Design 1.4 Summary 1.5 To Probe Further 1 chapter1.fm Page 2 Thursday, August 17, 2000 4:43 PM 2 INTRODUCTION Chapter 1 1.1A Historical Perspective The concept of digital data manipulation has made a dramatic impact on our society. One has long grown accustomed to the idea of digital computers. Evolving steadily from main- frame and minicomputers, personal and laptop computers have proliferated into daily life. More significant, however, is a continuous trend towards digital solutions in all other areas of electronics. Instrumentation was one of the first noncomputing domains where the potential benefits of digital data manipulation over analog processing were recognized. Other areas such as control were soon to follow. Only recently have we witnessed the con- version of telecommunications and consumer electronics towards the digital format. Increasingly, telephone data is transmitted and processed digitally over both wired and wireless networks. The compact disk has revolutionized the audio world, and digital video is following in its footsteps. The idea of implementing computational engines using an encoded data format is by no means an idea of our times. In the early nineteenth century, Babbage envisioned large- scale mechanical computing devices, called Difference Engines [Swade93]. Although these engines use the decimal number system rather than the binary representation now common in modern electronics, the underlying concepts are very similar. -
A Micro-Programmable Correlator for Real-Time Radar Processing
ALKER: Correlator for radar processing A MICRO-PROGRAMMABLE CORRELATOR FOR REAL-TIME RADAR PROCESSING by Hans-J¢rgen Alker ELECTRONICS RESEARCH LABORATORY (ELAB) Trondheim, NORWAY ABSTRACT This paper presents a novel design of a mul tibi t ·, digital correlator for incoherent scatter radar observations. By utilizing bit-slice microprocessor elements and internal control by microcode instructions, a high-speed arithmetical preprocessor has been developed. Arithmetical and control operations are separated to obtain increased speed performance. The arithmetical part is optimized for complex auto/cross correlation processing and has an effective rate of 24·106 multiplications/sec. Input data has 8-bit accuracy in integer format. The processor includes, at input, a 2-ported buffer memory for storing single/multiple channel inputs. Processing results are temporarily stored in a 4 K word high-speed memory before transferred to a general-purpose computer. Processing speed can be increased by adding up to 3 slave processors thus achieving direct parallel processing. Internal hardware is available for interface with standard CAMAC modules. INTRODUCTION During 1976-79 a feasibility study of a digital, multibit correlator for the EISCAT (European Incoherent SCATter) radar system was conducted. The main topics of the study embraced system design and hardware construction of a digital processor which fulfilled the specifications for real-time data process- ing. The result of the study is a prototype construction of a high- speed multiprocessor system under interactive control of the EISCAT radar site computer. Support software for microprogram development, simulation and hardware testing are available for execution on a host computer. The main objectives for constructing a digital processor for the EISCAT system were the ultimate requirements for special purpose data handling algorithms and the real-time processing speed. -
Hardware Design Techniques
HARDWARE DESIGN TECHNIQUES ANALOG-DIGITAL CONVERSION 1. Data Converter History 2. Fundamentals of Sampled Data Systems 3. Data Converter Architectures 4. Data Converter Process Technology 5. Testing Data Converters 6. Interfacing to Data Converters 7. Data Converter Support Circuits 8. Data Converter Applications 9. Hardware Design Techniques 9.1 Passive Components 9.2 PC Board Design Issues 9.3 Analog Power Supply Systems 9.4 Overvoltage Protection 9.5 Thermal Management 9.6 EMI/RFI Considerations 9.7 Low Voltage Logic Interfacing 9.8 Breadboarding and Prototyping I. Index ANALOG-DIGITAL CONVERSION HARDWARE DESIGN TECHNIQUES 9.1 PASSIVE COMPONENTS CHAPTER 9 HARDWARE DESIGN TECHNIQUES This chapter, one of the longer of those within the book, deals with topics just as important as all of those basic circuits immediately surrounding the data converter, discussed earlier. The chapter deals with various and sundry circuit/system issues which fall under the guise of system hardware design techniques. In this context, the design techniques may be all those support items surrounding a data converter, excluding the data converter itself. This includes issues of passive components, printed circuit design, power supply systems, protection of linear devices against overvoltage and thermal effects, EMI/RFI issues, high speed logic considerations, and finally, simulation, breadboarding and prototyping. Some of these topics aren't directly involved in the actual signal path of a design, but they are every bit as important as choosing the correct device and surrounding circuit values. Remote sensing and signal conditioning is such a vital part of data conversion that a considerable amount of discussion is given to topics such as overvoltage protection, cable driving, shielding, and receiving—where the remote interface is often with op amps and instrumentation amplifiers. -
MAS.632 Conversational Computer Systems
MIT OpenCourseWare http://ocw.mit.edu MAS.632 Conversational Computer Systems Fall 2008 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms. 10 Basics of Telephones This and the following chapters explain the technology and computer applica tions oftelephones, much as earlier pairs ofchapters explored speech coding, syn thesis, and recognition. The juxtaposition of telephony with voice processing in a single volume is unusual; what is their relationship? First, the telephone is an ideal means to access interactive voice response services such as those described in Chapter 6. Second, computer-based voice mail will give a strong boost to other uses of stored voice such as those already described in Chapter 4 and to be explored again in Chapter 12. Finally, focusing on communication,i.e., the task rather than the technology, leads to a better appreciation of the broad intersec tion of speech, computers, and our everyday work lives. This chapter describes the basic telephone operations that transport voice across a network to a remote location. Telephony is changing rapidly in ways that radically modify how we think about and use telephones now and in the future. Conventional telephones are already ubiquitous for the business traveler in industrialized countries, but the rise in personal, portable, wireless telephones is spawning entirely new ways of thinking about universal voice connectivity. The pervasiveness of telephone and computer technologies combined with the critical need to communicate in our professional lives suggest that it would be foolish to ignore the role of the telephone as a speech processing peripheral just like a speaker or microphone.