Time–frequency analysis | Wavelets | Signal processing
A wavelet is a wave-like oscillation with an amplitude that begins at zero, increases or decreases, and then returns to zero one or more times. Wavelets are termed a "brief oscillation". A taxonomy of wavelets has been established, based on the number and direction of its pulses. Wavelets are imbued with specific properties that make them useful for signal processing. For example, a wavelet could be created to have a frequency of Middle C and a short duration of roughly one tenth of a second. If this wavelet were to be convolved with a signal created from the recording of a melody, then the resulting signal would be useful for determining when the Middle C note appeared in the song. Mathematically, a wavelet correlates with a signal if a portion of the signal is similar. Correlation is at the core of many practical wavelet applications. As a mathematical tool, wavelets can be used to extract information from many different kinds of data, including – but not limited to – audio signals and images. Sets of wavelets are needed to analyze data fully. "Complementary" wavelets decompose a signal without gaps or overlaps so that the decomposition process is mathematically reversible. Thus, sets of complementary wavelets are useful in wavelet-based compression/decompression algorithms, where it is desirable to recover the original information with minimal loss. In formal terms, this representation is a wavelet series representation of a square-integrable function with respect to either a complete, orthonormal set of basis functions, or an overcomplete set or frame of a vector space, for the Hilbert space of square integrable functions. This is accomplished through coherent states. In classical physics, the diffraction phenomenon is described by the Huygens–Fresnel principle that treats each point in a propagating wavefront as a collection of individual spherical wavelets. The characteristic bending pattern is most pronounced when a wave from a coherent source (such as a laser) encounters a slit/aperture that is comparable in size to its wavelength. This is due to the addition, or interference, of different points on the wavefront (or, equivalently, each wavelet) that travel by paths of different lengths to the registering surface. Multiple, closely spaced openings (e.g., a diffraction grating), can result in a complex pattern of varying intensity. (Wikipedia).
Wavelets: a mathematical microscope
Wavelet transform is an invaluable tool in signal processing, which has applications in a variety of fields - from hydrodynamics to neuroscience. This revolutionary method allows us to uncover structures, which are present in the signal but are hidden behind the noise. The key feature of w
From playlist Fourier
Understanding Wavelets, Part 1: What Are Wavelets
This introductory video covers what wavelets are and how you can use them to explore your data in MATLAB®. •Try Wavelet Toolbox: https://goo.gl/m0ms9d •Ready to Buy: https://goo.gl/sMfoDr The video focuses on two important wavelet transform concepts: scaling and shifting. The concepts ca
From playlist Understanding Wavelets
Solution to problems dealing with the Doppler effect.
From playlist Physics - Waves
Solution to problems dealing with the Doppler effect.
From playlist Physics - Waves
Explaining the Doppler effect. Worked problems.
From playlist Physics - Waves
The What is a Wave? Tutorial describes in plain-language the characteristics of waves and the manner in which wave motion differs from other types of motion. Numerous examples, illustrations, and animations will help you get a good start with waves. You can find more information that supp
From playlist Vibrations and Waves
An introduction to the wavelet transform (and how to draw with them!)
The wavelet transform allows to change our point of view on a signal. The important information is condensed in a smaller space, allowing to easily compress or filter the signal. A lot of approximations are made in this video, like a lot of missing √2 factors. This choice was made to keep
From playlist Summer of Math Exposition Youtube Videos
Waves 2_10 General Differential Equation of Waves
Developing the general differential equation for any wave.
From playlist Physics - Waves
Glen Evenbly: "Using tensor networks to design improved wavelets for image compression"
Tensor Methods and Emerging Applications to the Physical and Data Sciences 2021 Workshop II: Tensor Network States and Applications "Using tensor networks to design improved wavelets for image compression" Glen Evenbly - Georgia Institute of Technology, Physics Abstract: Tensor networks
From playlist Tensor Methods and Emerging Applications to the Physical and Data Sciences 2021
Wavelets and Multiresolution Analysis
This video discusses the wavelet transform. The wavelet transform generalizes the Fourier transform and is better suited to multiscale data. Book Website: http://databookuw.com Book PDF: http://databookuw.com/databook.pdf These lectures follow Chapter 2 from: "Data-Driven Science an
From playlist Data-Driven Science and Engineering
Morlet wavelets in time and in frequency
Convolution requires two time series: The data and the kernel. The data is what you already have (EEG/MEG/LFP/etc); here you will learn about the most awesomest kernel for time-frequency decomposition of neural time series data: The Morlet wavelet. The video uses files you can download fr
From playlist OLD ANTS #3) Time-frequency analysis via Morlet wavelet convolution
Stéphane Mallat: A Wavelet Zoom to Analyze a Multiscale World
Abstract: Complex physical phenomena, signals and images involve structures of very different scales. A wavelet transform operates as a zoom, which simplifies the analysis by separating local variations at different scales. Yves Meyer found wavelet orthonormal bases having better propertie
From playlist Abel Lectures
Understanding Wavelets, Part 2: Types of Wavelet Transforms
Explore the workings of wavelet transforms in detail. •Try Wavelet Toolbox: https://goo.gl/m0ms9d •Ready to Buy: https://goo.gl/sMfoDr You will also learn important applications of using wavelet transforms with MATLAB®. Video Transcript: In the previous session, we discussed wavelet co
From playlist Understanding Wavelets
Effects of Morlet wavelet parameters on results
There is one important parameter of Morlet wavelets, which is the width of the Gaussian (a.k.a. the "number of cycles"). In this video we will explore this parameter and see what effects different parameter values have on the results. I will also provide some advice for when you should use
From playlist OLD ANTS #3) Time-frequency analysis via Morlet wavelet convolution
Image Compression and Wavelets (Examples in Matlab)
This video shows how to compress images with Wavelets (code in Matlab). Book Website: http://databookuw.com Book PDF: http://databookuw.com/databook.pdf These lectures follow Chapter 3 from: "Data-Driven Science and Engineering: Machine Learning, Dynamical Systems, and Control" by Brun
From playlist Data-Driven Science and Engineering
Angela Kunoth: 25+ Years of Wavelets for PDEs
Abstract: Ingrid Daubechies' construction of orthonormal wavelet bases with compact support published in 1988 started a general interest to employ these functions also for the numerical solution of partial differential equations (PDEs). Concentrating on linear elliptic and parabolic PDEs,
From playlist Numerical Analysis and Scientific Computing
Waves 2_11 General Differential Equation of Waves
Developing a general differential equation for any wave.
From playlist Physics - Waves