#wavelets

2025-06-18

When I was in #CS grad school, back in the early 1990s, #wavelets were hot in 3D volumetric CGโ€”oh, those SIGGRAPH symposia on the topic. At the same time in #EE, loads of papers were published on their efficacy in DSP. Just about everyone in EE and CS seemed to have published at least one paper on wavelets. Fun times. But the current state of wavelet academic #research seemed to have dried up.

I don't quite understand why wavelet transform has not supplanted Fourier transform in many #engineering and #computing application domains, considering its estimable time-frequency locality and its prodigious multi-resolution analysis capabilities, compared to Fourier analysis.

I am but a mere "maths carpenter". So, what am I missing, I wonder.

2025-03-21

Wavelet-Based Spectrum Analyzer! ๐ŸŽถ

FFT has long been the go-to method for visualizing audio spectra, but what if thereโ€™s a faster and more efficient alternative? Enter the Haar Wavelet Transform: a technique that provides logarithmic frequency resolution while being even more computationally efficient than FFT-based analysis.

Stay tuned for a deep dive into how wavelets can be used for real-time spectral analysisโ€”no FFTs required!

Some preview: gist.github.com/ashafq/99d468d

#dsp #wavelets #audio #programming #signalprocessing

2025-01-09

Hubbardโ€™s โ€œThe World According to #Waveletsโ€ is, by far, the most accessible book on the subject for non-engineers.

Robotics papersrobotics_papers
2024-11-27

MotionWavelet: Human Motion Prediction via Wavelet Manifold Learning

Authors: Yuming Feng, Zhiyang Dou, Ling-Hao Chen, Yuan Liu, Tianyu Li, Jingbo Wang, Zeyu Cao, Wenping Wang, Taku Komura, Lingjie Liu

pre-print -> arxiv.org/abs/2411.16964
website -> frank-zy-dou.github.io/project

2024-04-23

'ptwt - The PyTorch Wavelet Toolbox', by Moritz Wolter, Felix Blanke, Jochen Garcke, Charles Tapley Hoyt.

jmlr.org/papers/v25/23-0636.ht

#wavelet #wavelets #pytorch

2024-03-07

โ˜• Here's a bit of technical content from me - today a deep dive on #baseline correction methods.

๐Ÿ“ˆ Baseline correction is a preprocessing technique to remove background signal and isolate peaks in hashtag#spectroscopy data.

๐Ÿ“ In my recent post I discuss two methods:
1. Wavelet transform (WT) - Decomposes signal into components at different frequencies. Lowest frequency component represents baseline and can be removed.
2. Asymmetric least squares (ALS) - Fits a smooth baseline function, penalising positive deviations more than negative ones.

TL;DR: WT method is intuitive but can distort peaks. ALS produces better results.

๐Ÿ”Ž Both methods are applied on a #Raman spectrum and an X-ray fluorescence (#XRF) spectrum. ALS gives a cleaner baseline correction and it's effective for removing broad, slowly varying background while preserving sharper spectral features.

#chemometrics #Python #MachineLearning #wavelets #regression

nirpyresearch.com/two-methods-

Academic Publishingjellysmile
2023-12-11

๐—๐—ผ๐˜‚๐—ฟ๐—ป๐—ฎ๐—น ๐—ผ๐—ณ ๐—˜๐—ป๐˜ƒ๐—ถ๐—ฟ๐—ผ๐—ป๐—บ๐—ฒ๐—ป๐˜๐—ฎ๐—น & ๐—˜๐—ฎ๐—ฟ๐˜๐—ต ๐—ฆ๐—ฐ๐—ถ๐—ฒ๐—ป๐—ฐ๐—ฒ๐˜€ | ๐—ฉ๐—ผ๐—น๐˜‚๐—บ๐—ฒ ๐Ÿฌ๐Ÿฐ | ๐—œ๐˜€๐˜€๐˜‚๐—ฒ ๐Ÿฌ๐Ÿฎ | ๐—ข๐—ฐ๐˜๐—ผ๐—ฏ๐—ฒ๐—ฟ ๐Ÿฎ๐Ÿฌ๐Ÿฎ๐Ÿฎ

๐—๐—ผ๐˜‚๐—ฟ๐—ป๐—ฎ๐—น ๐—ผ๐—ณ ๐—˜๐—ป๐˜ƒ๐—ถ๐—ฟ๐—ผ๐—ป๐—บ๐—ฒ๐—ป๐˜๐—ฎ๐—น & ๐—˜๐—ฎ๐—ฟ๐˜๐—ต ๐—ฆ๐—ฐ๐—ถ๐—ฒ๐—ป๐—ฐ๐—ฒ๐˜€ | ๐—ฉ๐—ผ๐—น๐˜‚๐—บ๐—ฒ ๐Ÿฌ๐Ÿฐ | ๐—œ๐˜€๐˜€๐˜‚๐—ฒ ๐Ÿฌ๐Ÿฎ | ๐—ข๐—ฐ๐˜๐—ผ๐—ฏ๐—ฒ๐—ฟ ๐Ÿฎ๐Ÿฌ๐Ÿฎ๐Ÿฎ ๐ŸŒ Quantum Biophysics of the Atmosphere: Asymmetric Wavelets of the Average Annual Air Temperature of Irkutsk for 1820-2019 ๐Ÿ‘‰ The regularities of the dynamics of the average annual temperature of Irkutsk from 1820 to 2019 were revealed. ๐Ÿ”— DOI: โœ‰โ€ฆ

myfavorite621.wordpress.com/20

2023-09-24

"Binlets: Data fusion-aware denoising enables accurate and unbiased quantification of multichannel signals", Silberberg & Grecco, 2023 sciencedirect.com/science/arti

Old school signal processing, not based on machine learning but instead on a translation-invariant Haar wavelet decomposition, profitably exploiting correlations across channels. The manuscript includes an accessible and brief "Theory" section and a longer appendix. All it needs to run is a test function between two data points.

In their benchmarks and use cases, the new method outperforms existing denoising methods. In both time series and on fluorescent microscopy images.

There's a repository available github.com/maurosilber/binlets and can be installed with `pip install binlets`.

#denoising #SignalProcessing #wavelets #ComputerVision

Fig. 6. Denoising applied to fluorescence microscopy images of cells. (left) Intensity images for the ground truth, raw, and raw denoised with binlets and two deep learning methods (N2N and DnCNN). The color scale changes slope at 9 to highlight differences in three areas: nucleus, the rest of the cell, and background. Residuals were calculated against the ground truth, which is the average of 50 raw images, and normalized with their standard deviation. (top-right) Mean and standard deviation for the metrics applied to the whole dataset: root mean squared error improvement (RMSE improv., normalized to raw) and mean bias. They were calculated in three regions: the whole image (all), background and cell areas. (bottom right) Residual mean intensity for each nucleus between the denoised and ground truth images as a function of the ground truth mean intensity. The error bars correspond to the standard deviation of the 50 samples.
2023-05-20

Wavelet decomposition is very popular in image analysis and processing. Here's my attempt to share some code to perform spectral smoothing (or denoising, to be fancy) using the same principle.

Wavelet denoising of spectra โ€ข NIRPY Research
nirpyresearch.com/wavelet-deno

#ImageProcessing #chemometrics #spectroscopy #wavelets #DataProcessing

Small waves on the sea surface.
Ko-Fan Chen ้™ณๅ…‹ๅธ†kofanchen@drosophila.social
2022-11-09

@orieshafer
That is cool, I have not yet used #wavelets d you have a good suggestion for software package including it? I still use #flytoolbox from Joel Levine (ps is he on #mastodon)

sofia โ˜ฎ๏ธ๐Ÿดsofia@chaos.social
2022-08-28

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