# Tagged Questions

A wavelet is a wave-like oscillation with an amplitude that starts out at zero, increases, and then decreases back to zero.

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### Raw signal to short for DWT

The algorithm i use to apply a discrete wavelet transform only accept raw-data with a certain number of samples (2,4,8,..128..). I have to either interpolate the raw signal or padding it with zeros (...
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### Discrete wavelet transform

I am unable to understand the discrete wavelet transform on images. I followed Robi Polikar's tutorial and got a brief idea about the theory. But I'm unable to understand w.r.t images. Using Matlab's ...
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### Extract the frequency range/mean from time series using Wavelet

I am working with Wavelet for the first time, and I need your help. I have time series of velocity collected for 2 min at 32 Hz: x = [n] where n = 120 (sec)*32 = 3840 counts. I am using Morlet ...
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### questions on the wavelet digital filters

I am new in wavelet transform and digital filters. My knowledge on wavelet transforms was mainly from its applications with the implementation using Matlab or mathematica. So my question might be too ...
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### Wavelet transform of time series(PyWavelets)

I am a newbie in wavelet transform and I would be glad if you help me. I have different time series(ECG with rate = 1000 points in second, length = 100 000 points). I need to classify them in two ...
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### How to find the energy of a single frequency from its time-frequency distribution?

I have a non-stationary time series. I am interested in finding the energy content of a single frequency (actually the ratio of that single frequency over the total energy of the signal). The problem ...
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### Question about vanishing moments in wavelet tranforms

I am reading the book Noise reduction by wavelet thresholding by Maarten Jansen. About vanishing moments, it reads To create a really sparse representation, we try to make coefficients that ...
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### What are the spike removal techniques in matlab without using filters

output from wavelet filter using daubechies 4 wavelet. Using wavelet filter this is the output obtained. The problem is elimination of the spikes at 0.023,0.043,0.063 and so on. Please note: no ...
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### Daubechies wavelet transform

i have N samples obtained by sampling a signal with lot of frequency contents. How will i apply daubechies wavelet transform to obtain the frequency and its location? i need to write a program which ...
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### Interpretation of Diagonal detail wavelets

I am a statistics grad student, and I have just begun exploring the topic of wavelet regression (specifically, Haar wavelets for discrete functions). I understand the generalization from a one ...
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### Undecimated discrete wavelet transform in Python and Matlab

Loosely based on the above figure: I need to make an array like this: array = [(image),(1,ll),(1,lh),(1,hl),(2,ll),(2,lh),(2,hl)] Here, image is a numpy 2D ...
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### Cohen-Daubechies-Fauraue 7/9 wavelet in Matlab

I just want to ask what the wavelet filter name used for Cohen-Daubechies-Fauraue 7/9. what name should I used in 'wname' when I want to use this type of wavelet in Matlab. some say that it is bior4....
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### Compression Ratio in ECG compression using Wavelet Decomposition

I have compressed and reconstructed an ECG signal using Wavelet Coefficient. In compressing part, many of Wavelet Coefficient have set to zero. for example, if in original ECG, 5000 wavelet ...
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### How to do edge detection using Curvelet transform?

I wanted to use Curvelet thresholding for edge detection, that is first take discrete curvelet transform then choose coefficient which are for curve and then reconstruct back to get an edge map. ...