## Forums Search for: Wavelets

## Adaptive Spike Detection & Wavelet Coefficient

inHi Friends, I am working this area, is there any method you can suggest me to adaptively detect spikes in biological signals which...

Hi Friends, I am working this area, is there any method you can suggest me to adaptively detect spikes in biological signals which are non-stationary and random in nature... a trival method if possible can you please let me know. Secondly, how to choose which wavelet decomposition would be favourable to signals whose dynamics nature is unpredicated. Regards Rajeev Yadav This message...

## wavelets, 2-D complex morlet code in MATLAB

incan anybody help me find MATLAB code for 2-D complex morlet wavelet? any web resource or book will be ok. thanks!

can anybody help me find MATLAB code for 2-D complex morlet wavelet? any web resource or book will be ok. thanks!

## Images in Wavelet

inHello, when the use of wavelets comes to images, I want to know: Why decomposition starts with the row wise and then column wise..can we...

Hello, when the use of wavelets comes to images, I want to know: Why decomposition starts with the row wise and then column wise..can we get the same by doing otherway, i.e. column wise and then row wise? This message was sent using the Comp.DSP web interface on www.DSPRelated.com

## shift theorem

inIs there such thing as a shift-theorem* for filterbanks other than the discrete fourier transform? For example the discrete cosine...

Is there such thing as a shift-theorem* for filterbanks other than the discrete fourier transform? For example the discrete cosine transform, the cosine modulated filterbank, the discrete wavelet transform? * The shift theorem for the DFT states that if Y(m) is the m-th DFT coefficient of y(n) then DFT[y(n-k)]_m = exp(j.2pi.k/N).Y(m) (This assumes that y(n) is periodic)

## Hidden markov models implementaion

inSir i have problem using HMM for speech recognition.... My problem statement is that i want to identify the sequence of arabic phonemes present...

Sir i have problem using HMM for speech recognition.... My problem statement is that i want to identify the sequence of arabic phonemes present in the speech file... I have calculated certain features like MFCC, wavelet, spectrogram etc for the speech file. These features are in numerical format ( not probabilities ). There are 28 arabic phonemes. I have studied some literature related to HMM...

## wavelet transform

inIs there any difference between the wavelet transform using filter banks and the subband coding? thanks This message was sent using the...

Is there any difference between the wavelet transform using filter banks and the subband coding? thanks This message was sent using the Comp.DSP web interface on www.DSPRelated.com

## Wavelet filters

inHello i am trying to implement a wavelet transform using digital filters! Could anyone tell me how to design these filters. I have tried to...

Hello i am trying to implement a wavelet transform using digital filters! Could anyone tell me how to design these filters. I have tried to use matlab command FIR1 but it seems not to be a good way to design these filters! Thank for your help This message was sent using the Comp.DSP web interface on www.DSPRelated.com

## The coefficients of the analysis filter

inHello Is there anyone who could give me a hint on how to get the coefficients of the analysis filters! Thanks ! Hi, > > Isn't it...

Hello Is there anyone who could give me a hint on how to get the coefficients of the analysis filters! Thanks ! Hi, > > Isn't it correct that the "dbaux command" gives the coefficients of the > wavelet reconstruction filters? Any suggestion on which command to use in > order to get the coefficients of the analysis filter. > I am using matlab version 7.0! > > Thanks for your time! >

## Removing White Noise

inHey everyone, I have an audio application, and I'm trying to do some pre/post processing to improve the sound quality. I put in an adaptive...

Hey everyone, I have an audio application, and I'm trying to do some pre/post processing to improve the sound quality. I put in an adaptive filter to try and remove structured noise, but I'd like to remove white/pink noise from the signal somehow.. I've been looking at wavelet techniques, or whatever else I can find. Can anyone recommend a good way to reduce white noise from audio/ A...

## wavelet question

inHi I have just started reading about wavelets and I found the online tutorial by Polikar very helpfull for understanding the basics of the...

Hi I have just started reading about wavelets and I found the online tutorial by Polikar very helpfull for understanding the basics of the theory: http://users.rowan.edu/~polikar/WAVELETS/WTpreface.html But there are some issues that I struggle with and I thought maybe you good people of comp.dsp can help me with. In part III of the above tutorial: (http://users.rowan.edu/~polikar/...

## How do I get from FWT to Log-Freq Spectrum?

inHow can I get from the Fast Wavelet Transform (such as using Wave++ library for example) to a Log-Frequency Spectrum? I understand...

How can I get from the Fast Wavelet Transform (such as using Wave++ library for example) to a Log-Frequency Spectrum? I understand fourier theory fairly well (for a computer programmer) and the basics of discrete wavelet transforms. I understand how the discrete wavelet transform can be compared to a constant-q filter bank. What I don't understand is how can the different signals from the "...

## 1D Discrete wavelet transform(DWT)

inHello I have a little question concerning the discrete wavelet transform! Let's consider one dimensional signal having a frequency up to 2kHz...

Hello I have a little question concerning the discrete wavelet transform! Let's consider one dimensional signal having a frequency up to 2kHz ( we consider that the sampling frequency is then 4kHz)which is filtered with low and highpass FIR filters, let this be the first decomposition level!! After passing the signal through a lowpass filter, half of the samples can be eliminated according ...

## algorithm of Inverse discrete wavelet transform

inHello i was reading the roby polikar wavelet tutorial, and there is something i did not quite understand about the reconstuction formula for...

Hello i was reading the roby polikar wavelet tutorial, and there is something i did not quite understand about the reconstuction formula for DWT. here is the formula: after upsampling the signal the reconstructions goes this way: x[n]= sum(for k=-infinity to +infinity)(yhigh[k]*g[-n+2k]+(ylow[k]*h[-n+2k]) yhigh is the detail coefficients array ylow approximation coefficient k is the ...

## Which processor for processing guitar output

inHi All, I am currently trying to build a tool that is capable of providing information about the real time characteristics of the output of a...

Hi All, I am currently trying to build a tool that is capable of providing information about the real time characteristics of the output of a electric guitar. Bascially I want to determine what note (or combination of notes) is being played in real time, based on this info I will give some sort of feedback to the user. It has been suggested to me that I should use a wavelet transfor...

## Discrete wavelet transform

inHello I would like to ask if there is any difference between the following equations. Actually these are the wavelet equations for the...

Hello I would like to ask if there is any difference between the following equations. Actually these are the wavelet equations for the filtering and the downsampling! The 2 steps are combined in one! // yhigh[k] = sum_n(x[n]*g[2k-n]) is it the same as yhigh[n] = sum_k(x[2n-k]*g[k]) // ylow[k] = sum_n(x[n]*h[2k-n]) is it the same as ylow[k] = sum_n(x[n]*g[2k-n]) Can we assume tha...

## constant Q transform Vs wavelet transform

Hi, Constant Q transform is not the same as wavelet transform, right? thanks

Hi, Constant Q transform is not the same as wavelet transform, right? thanks

## Need help

inI want to know what is the mistake in my code below which I used to get Mother Wavelet in CCs,and by the same code I can get Mother Wavelet...

I want to know what is the mistake in my code below which I used to get Mother Wavelet in CCs,and by the same code I can get Mother Wavelet using Matlab. code in CCS: int i = 0; float morlet[1024]; int sgm = 64; float t; float f = 1000; double ts = 1/128; interrupt void c_int11() //interrupt service routine { t = -512*ts; for(i...

## Wavelet regularity condition

inHi, In the following link : http://perso.wanadoo.fr/polyvalens/clemens/wavelets/wavelets.html#section3 the writer hasn't put the bounds on...

Hi, In the following link : http://perso.wanadoo.fr/polyvalens/clemens/wavelets/wavelets.html#section3 the writer hasn't put the bounds on the integral. Do you know which the bounds are? In my country I don't have the ability to buy the book that the writer refers to. thank you.

## discrete-time wavelet transform vs discrete wavelet transform vs integer wavelet transform

inHi, I am very confused about the names of discrete wavelet transform and I don't know what to do. In the book "Wavelets and subband coding"...

Hi, I am very confused about the names of discrete wavelet transform and I don't know what to do. In the book "Wavelets and subband coding" and in the book "Introduction to data compression" says that the discrete-time wavelet transform is a wavelet series that uses continuous function but the corresponing transform is discrete. The discrete wavelet transform is the one that everything ...

## audio processing

inHow to read a wav file using c and to perform discrete wavelet trans for it?

How to read a wav file using c and to perform discrete wavelet trans for it?