## Forums Search for: Wavelets

## wavelet coefficient

inhi all, how to calculate the wavelet coefficients for Daub-4 or Daub-6 wavelets? thanx and regards

hi all, how to calculate the wavelet coefficients for Daub-4 or Daub-6 wavelets? thanx and regards

## Uncertainty limit!!

inHi, After 11 PM message: Can anybody help with the uncertainty limit of both Wigner distribution and Wavelet transform and give some light ...

Hi, After 11 PM message: Can anybody help with the uncertainty limit of both Wigner distribution and Wavelet transform and give some light comparing on that ground? Regards, Santosh

## Wavelet ON/OFF

inI know this question is awfully silly. But I just want to make sure that it IS indeed as simple as this and that I havent missed anything. I...

I know this question is awfully silly. But I just want to make sure that it IS indeed as simple as this and that I havent missed anything. I have a file of raw data bits from a signal capture board. I havent seen this file. But I know it's rather huge and that it has 0s and 1s. I need to run this file through a function and determine the ON and OFF periods of the signal. Sounds simple....

## Definition of wavelet?

inHi comp.dsp, One quick question: does the difinition of wavelet require at least one vanishing moment, or not? In other words, can the...

Hi comp.dsp, One quick question: does the difinition of wavelet require at least one vanishing moment, or not? In other words, can the discrete filter {2, -1} be considered as wavelet? (i believe it has the corresponding scaling function: {2, 1} - and they form the orthogonal basis together) Thanks. Alex

## shift theorem for wavelets (with application to OFDM)

inIn an OFDM signal, if the symbol window (of N samples) is misaligned at the input to the FFT, the constellation points on each tone are rotated...

In an OFDM signal, if the symbol window (of N samples) is misaligned at the input to the FFT, the constellation points on each tone are rotated by a certain amount. To undo this effect we use the Fourier shift theorem which allows us multiply by a complex exponential on each tone. I am using a Wavelet Packet Transform instead of an FFT. My question is, is there an equivalent time/scale shi...

## wavelet question

inhi all, Can anyone tell why wavelets are better than subband coding in image compression? thanx, sridevi

hi all, Can anyone tell why wavelets are better than subband coding in image compression? thanx, sridevi

## what is the nonseparable wavelet transform for 2D image?

inI heard this a lot times, but don't know what it is and how to implement in matlab? Can anybody teach me a little bit on this?

I heard this a lot times, but don't know what it is and how to implement in matlab? Can anybody teach me a little bit on this?

## seeking advice on study wavelet -- any good wavelet learning material

inDear all, Wavelet is really hard to learn and master. However I need to learn it by self-study. I have read Martin Vetterli's book and...

Dear all, Wavelet is really hard to learn and master. However I need to learn it by self-study. I have read Martin Vetterli's book and Mallat's book. For both books I can only understand the first 1/3 part of the books. I always understand the Haar example, but after that, math becomes dominant and horrible. I understand that in order to understand the books and learn/master wavelet wel...

## Information on wigner-ville distribution

inHello I want to learn and simulate Wigner- ville distribution(WVD). I have a basic idea about time-frequency analysis like STFT and wavelet...

Hello I want to learn and simulate Wigner- ville distribution(WVD). I have a basic idea about time-frequency analysis like STFT and wavelet analysis. WVD is also a type of time-frequency analysis (isn't it?), but what is the underlying difference with respect to the above methods. Where can I find some description about WVD? preferably which talks about discrete-time WVD also. Thanks...

## Hardware for Wavelets

inHi... I am planning a system where we will have brain data (EEG) input, and we need to do spectral analyses as fast as possible. Computer will...

Hi... I am planning a system where we will have brain data (EEG) input, and we need to do spectral analyses as fast as possible. Computer will be an IBM 2.2 ghz dual Opteron. Are there boards with chips which can perform a Wavelet analysis? I know there are FFT processors. Thanks in advance, Jim

## Noise characterization of wavelet coefficients

inHi, I hope this question about wavelets is not too far off topic in this forum... I have some image data with noise for which the noise...

Hi, I hope this question about wavelets is not too far off topic in this forum... I have some image data with noise for which the noise statistics (mean, variance) are known : noisy image = true image + noise in image domain In my case, the mean and variance is not constant over the image (correlated noise). When I perform a wavelet transform on this noisy image, I presume I can ...

## Wavelet Pages Update

inDear comp.dsp Folks, In the last days I made a very large maintenance of my wavelet pages. The software and bibliography pages have...

Dear comp.dsp Folks, In the last days I made a very large maintenance of my wavelet pages. The software and bibliography pages have increased substantially, in addition to an update of the links on all of the pages. Details about the changes can be seen on the 'Recent Modifications' page. This summer marks nine years of these pages, so I wrote a retrospective, which you can read at th...

## Localization method simpler than using Wavelet

inAlthough analysing signals with Wavelet has the benefit of localization, the functions used for Wavelet are a bit complicated. Don't you think...

Although analysing signals with Wavelet has the benefit of localization, the functions used for Wavelet are a bit complicated. Don't you think so? Using the complete function system simpler than that of Wavelet introduced in the following webpage: http://139.134.5.123/tiddler2/fbt/fbt.htm the software: FBT can carry out spectral analysis in the order of O(n) where n is the number of sam...

## wavelet based analysis for speech processing!

inSpeech is short stationary signals. Can anybody use "wavelet transform" for speech/voice or audio processing? Do they get any extra benefit out...

Speech is short stationary signals. Can anybody use "wavelet transform" for speech/voice or audio processing? Do they get any extra benefit out of it e.g using variable window size - since speech is sparse in nature also? How about complexity of wavelet based analysis compared to conventional LPC analysis - the question just came out of head. Regards, Santosh

## Going from FFT to Wavelets

inHi, This is my first post to this interesting newgroup. I have been analyzing sound samples (muic) using FFT with some success. I can...

Hi, This is my first post to this interesting newgroup. I have been analyzing sound samples (muic) using FFT with some success. I can calculate frequency, amplitude and phase for the frames. But I face the known frequency / time resolution dilemma. This has made me experiment with wavelets. So far I have only tried the Haar wavelet. I have made test files with sine waves of frequencie...

## calculating daubechies coefficients

inI understand that you perform the inner products of the signal with the wavelet and the scaling functions to get the coefficients. But I have...

I understand that you perform the inner products of the signal with the wavelet and the scaling functions to get the coefficients. But I have two questions about the prcoess: 1. Do I perform the products of all three variables (ie: signal.scaling.wavelet) to get the coefficients, or do I perform two separate calculations (ie: signal.scaling and signal.wavelet)? 2. What values of ...

## DSP books

inHi, I have just bought these books: "Understanding Digital Signal Processing", by Richard G. Lyons "Introduction to Signal Processing", by...

Hi, I have just bought these books: "Understanding Digital Signal Processing", by Richard G. Lyons "Introduction to Signal Processing", by Orfanidis "A Wavelet Tour of Signal Processing", by Stephane Mallat I must say that I really like Richard's book. It is very accessible and informative. The others are a little hard to understand mathematically. I am thinking about buying the bo...

## Wiener filters for transient deconvolution

inHi folks. I'm sitting here with some data recorded by a sonar. The sonar is directed vertically, insonifying a layered sea floor. My job is...

Hi folks. I'm sitting here with some data recorded by a sonar. The sonar is directed vertically, insonifying a layered sea floor. My job is to try to estimate the reflection series for this sea floor. I have both a nominal source wavelet (i.e. the analytical expression for the emitted pulse) and a reference recording, where the sonar was directed towards a reciever that was suspended ...

## Wavelet PDE Matlab Sought

inWhat MatLab Packages are there for solving PDEs using WaveLets? This problem has been solved with Collocation up to now, but I need...

What MatLab Packages are there for solving PDEs using WaveLets? This problem has been solved with Collocation up to now, but I need the inputs and outputs to be in WaveLet form for upstream and downstream analysis. - = - Vasos-Peter John Panagiotopoulos II, Columbia'81+, Bio$trategist BachMozart ReaganQuayle EvrytanoKastorian http://ourworld.compuserv...

## need help in deciding a DSP solution

inI am searching for a DSP board ( TI TMS320C6x series of processor), which would take 21 channels of analog EEG signals convert it to digital...

I am searching for a DSP board ( TI TMS320C6x series of processor), which would take 21 channels of analog EEG signals convert it to digital with a sampling rate of 256Hz and process (such as doing wavelet transformation) individually and parallelly of each individual channel. please suggest me a DSP board or plan to implement thanks