Presentation on theme: "Kalasalingam University"— Presentation transcript:
1 Kalasalingam University Kalasalingam University, Digital Signal Processing and Applications, Nondestructive Evaluation using Barkhausen NoiseV.K. Madan, PhDBTech (IITD), PhD (IITB), PDF (U. Sask., Canada)Fellow: IETE, IE (India); LM: INS, IPA, NTSI, ASI, ISTESenior ProfessorKalasalingam UniversityEx: Scientific Officer (H), Bhabha Atomic Research Centre, MumbaiProfessor, Homi Bhabha National Institute , MumbaiProfessor, BITS, PilaniTeacher, PhD(Tech) Electronics Engrg, U of MumbaiResearch Board Member, Kalasalingam University
2 KALASALINGAM UNIVERSITY Kalasalingam Academy of Research and Education (under section 3 of UGC act 1956) Accredited by NAAC with B grade with CGPA of 2.81 on 4 point scale
3 VISIONTo Be a Centre of Excellence of International Repute in Education and ResearchMISSIONTo Produce Technically Competent, Socially Committed Technocrats and Administrators Through Quality Education and Research
4 MoU with International Universities Carnegie Mellon University, USAUniversity of Oklahoma, USABall State University, USAEast Tennessee State University, USAGeorgetown University, USAUniversity of Applied Sciences, Western SwitzerlandCentro De Investigacion Y De Estudios Avanzados Del IPN, MexicoINM Leibniz-Institute for New Materials gGmbH, H Saarbrucken, GermanyCentre for Combinatorics, Nankai University, ChinaHannam University, South KoreaSoongsil University, South KoreaTechnical University of Kosice, The Slovak RepublicGlobal Associations
5 Science, Technology, Art, Religion, Music … Earlier: One state scientist like Archimedes, Nobility, Professors, Common peopleNewton: Philosophy of Natural SciencePhilosophy: An obstinate attempt to think clearlyDisciplines, specializationMultidisciplinary, synthesis, fusion, merging of toolsHermann Hesse: The Glass Bead Game (Das Glasperlenspiel)Inspiration from Leonardo da Vinci: There is no man from whom I can’t learn somethingMoral: Keep mind open to all disciplines and try to integrate them with your expertise. Respect the great people but question their work.
6 John Masefield (Poet Laureate) Has come whatever worth man ever knew; Adventure on, for, from the littlest clueHas come whatever worth man ever knew;The next to lighten all men may be you
7 Digital Signal Processing (DSP) and Applications
9 What is DSP?Digital Signal Processing – the processing or manipulation of signals using digital techniquesDigital Signal ProcessorInput SignalOutput SignalADCDACAnalogue to Digital ConverterDigital to Analogue Converter
10 TransformsTransforms -- a mathematical conversion from one way of thinking to another to make a problem easier to solve.Example: Logarithmic transformationproblem in original way of thinkingsolution in original way of thinkingtransformsolutionin transformway ofthinkinginversetransform
11 DSP: Applied2012 IEEE Intl. Conf Emerging Signal Processing Applications (ESPA), Las Vegas (emerging applications)3D technology for gaming, telepresenceGesture recognition for games and natural user interfacesDigital photography4G wirelessRoboticsMultimedia tabletsSP in automobiles: speech interfaces, camerasVoice searchSP with multicore processorsIPTV
12 Dogma of Circle DSP The Greek Philosopher Plato Claudius Ptolemy (all the phenomena in the sky are produced by uniform and circular motion)Eudoxus: superposition of rotating spheres. Aristotle used upto 54 spheresClaudius Ptolemy replaced spheres by circlesVasco da Gamma IndiaColumbus AmericaMagellan worldNicholas CopernicusLuther: “fool “Johannes Kepler
13 Propagation of the Dogma of Circle Astronomy (disappeared) reappeared in Physics (eit) Electrical Engineering (ejt)Phasor: first used by Lord Raleigh in soundPhasor: introduced in EE by Oliver HeavisidePopularized by Kennelly and Steinmetz in USA in early 1900s. Still very important.Sinusoids are bread and butter of EEE
14 Circle: Astronomy to Power System, DSP, Communication Engineering Power System: Phasor AnalysisDSP: unit circle in the complex planeCommunication Engineering: modulatorModulatoror mixer
15 Faith vs Reason in Science Last 100 years Fourier transforms are being used. Only uses for which the transforms are good are developed. Selective development. However it generated lot of knowledge base.Arthur Koestler: The sleepwalkers (challenges the habitual idea of a progressive science)Fourier transforms:Don’t converge at discontinuity (Gibbs). Information intensive points: discontinuities.requires infinite sinusoidal waves.Noncausal: O/p before I/pNegative frequency
16 Faith vs Reason in Science (contd.) Fermat conjectured in 1640 that all the Fermatnumbers (22m + 1 ) are prime. In 1732 Euler pointed out that the Fermat number was not prime. (90 years)(Fermat numbers are useful in DSP)Minsky and Papert published from MIT in 1969 a book “Perceptron” and wrote "...our intuitive judgment that the extension (to multilayer systems) is sterile“. In simple language it means that multilayer perceptron cannot realize Exclusive-OR gate. The research in neural networks was halted for 10 years until it was proved that their judgement was wrong. (10 years).
17 FactsJ. Finlaison’s report to House of Commons, London 1829 (used digital filter)Many digital filters with excellent properties were existing in 19th century.FFT algorithm existed (1805) before Fourier transform (1822). Rediscovered in 1965.Fourier transform remained questionable till a paper by Norbert Wiener from MIT in 1930.Spread spectrum communication invented by by Hollywood actress Lamarr and composer Antheil. Used by US Navy during Cuba blocade by President Kennedy
18 Fourier TheoryFourier introduced the idea of representing an arbitrary periodic function as a trigonometric series, eminent mathematicians such as Lagrange resisted it.Till 1930 : Fourier theory was useful for analyzing periodic and aperiodic functions, but not for random functions.Norbert Wiener from MIT in applied Fourier theory for analyzing random functions. Presently it is known as “Wiener-Khinchin theorem'' stating that the power spectrum is the Fourier transform of signal’s autocorrelation function.
19 Fast FourierTransform (FFT) C.F. Gauss had written in 1805, 'Experience will teach the user that this method will greatly lessen the tedium of mechanical calculation.'this method is FFT. It was rediscovered by Cooley and Tukey in 1965."The FFT rediscovery has been called the most important numerical algorithm of our lifetime (Strang, 1994)." (Kent & Read 2002, 61)
20 A Peep Beyond Fourier Transform Numerous orthogonal transforms exist other than Fourier transform. Fourier transform is, however, most popular and most widely used compared to any other transform.Walsh-Hadamard transformNumber theoretic transformHartley transformHouseholder transformand many more . . .
21 Third Century Chinese Verse by Sun Tzu (useful in Computers) We have things of which we do not know the number,If we count them by three, the remainder is 2,If we count them by five, the remainder is 3,If we count them by seven, the remainder is 2,How many things are there?……..Moduli: 3, 5, 7Remainders: 2, 3, 2Answer: 23
22 Sanskrit, Vedic Arithematic (useful in computer Science) Multiply:byAnswer:Trick: ascending, descending, symmetrySquare: (52) x (52)Answer: (mental time 5 seconds)Trick: any number 30 to 7050/2 = 25+2 = 27 and 2x2 = 4
24 Cochlea: A bank of filters Human ears do not hear wave-like oscillations, but constant toneOften it is easier to work in the frequency domain(for cochlear animation: )
25 Analog, Discrete-time, and Digital Signal y(t) = A sin (2ft + )Analog signal?Discrete time signal?Digital signal: t and y(t) are quantized
26 Signal Classification Periodic and aperiodicDeterminstic and randomEnergy and powerAnalog and digitalType I and Type II (new classification)
27 New Classification of Digital Signals: Type I and Type II (Madan et al) Type I and Type II; based on fundamental problems of aliasing and quantization noise (q.n.). The classification has enhanced the scope of DSP in many disciplines:Type I: aliasing and q.n. are addressed along the abscissa and ordinate respectivelyType II: aliasing and q.n. are addressed along the abscissa
28 Type I and Type II Signals Type II: Nuclear spectra like gamma, x-ray spectra, population sciences etc.“DSP methods widely used for Type I signals, are generally not used for Type II signals.” DSP methods have demonstrated numerous advantages for processing Type II signals,… .”Presently not many Type II signals are processed employing DSP.
37 (DSP based: <2.5KB core part; 43KB full program) SAMPO has 25,000 lines of FORTRAN, 10,000 lines of C, and 12,000 lines of assembler(DSP based: <2.5KB core part; 43KB full program)IAEA Intercomparison(about SAMPO and other programs)“Evidently, therefore success in evaluating these spectra is not so much dependent on the principle of the method used.”SAMPO is still most popular. It has generated lot of knowledge base, friendly platform, available commercially…Some common examples where the rationality doen’t prevail:pounds vs. kgMetre vs. feet
38 PET cameraState of the art PET scanners are full-ring systems that completely surround the patient.
39 PET/CT CT PET CT+PET (Siemens in 2011) General Electric Medical Systems
40 Walsh ConvolutionArithmetic convolution is “the least successful area” using Walsh functionsAbsence of shift theorem“Computer processing… one of the best field of Walsh” functions
41 DSP Processor: Texas Instruments fixed-point/ floating point“Harvard architecture”separate instruction, data memoriesAccumulatorSpecialized instruction setLoad and AccumulateInstructionMemoryProcessorDataMemoryDatapath:MemT-RegisterMultiplierP-RegisterALUAccumulator
46 MBN Applications Residual stress in steel the level of carburisation(the increase of carbon content)Remaining-life estimates of critical component in operational plant, for example in thermal power stations and the petrochemical industry
47 MBN Applicationssurface treatments like grinding, shot peening, carburizing and induction hardening modify stress and microstructure.dynamic processes like creep and fatigue involve changes in stress and microstructureBarkhausen noise method is useful for the above
48 MBN ApplicationsBarkhausen noise analysis is uesful for surface defects, processes and surface treatments that may involve changes in both stresses and microstructure like:Detection of grinding defects and grinding process controlDetecting surface defects through Cr-coatingEvaluation of shot-peening effect in steelMeasurement of residual surface stresses in steel mill rolls and steel sheet
50 MBN Applications Controlling the quality of: grinding, heat treating, shot peening ormachining ofcamshafts, crankshafts, ball bearings, gears, valves, etc.
51 Barkhausen Noise Professor Heinrich Barkhausen in 1919 AKA: Magnetoelastic orMicromagnetic techniquemagnetic field is applied to a ferromagnetic sampleFerromagnetic materials: domains, separated from one another by boundaries known as domain walls
54 Barkhausen NoiseAC magnetic fields will cause domain walls to move back and forth.Coil of conducting wire is placed near the sample while the domain wall moves, the resulting change in magnetization will induce an electrical pulse in the coil.Magnetization process: hysteresis curve.Abrupt steps caused when the magnetic domains move under an applied magnetic field.When the electrical pulses by domain movements generate a noise-like signal called Barkhausen noise
55 Magnetoelastic Interaction Barkhausen Noise Signal measures elastic stressesmagnetoelastic interaction: elastic properties interacting with domain structure and magnetic properties of material.compressive stresses will decrease the intensity of Barkhausen noise.tensile stresses increase the intensity of Barkhausen noise.the intensity of Barkhausen noise helps determine the amount of residual stress