Questions tagged [wavelet-analysis]
Questions on the wavelet analysis functions of Mathematica.
55
questions
1
vote
1answer
41 views
Integral of a Wavelet function
I ran into problems integrating a function which contains both an If condition and a Wavelet which is an ...
3
votes
1answer
66 views
<<Wavelets`Wavelets Not Found [closed]
please i'm a student and i need help in my project which is based on an already existing program.
The problem that the program is ancient( Mathematica 5.0) and doesn't fit with the new versions of ...
2
votes
2answers
66 views
WaveletListPlot: Broken in 11.2?
I'm trying to create a WaveletListPlot, following the reference code exactly:
...
3
votes
1answer
94 views
1
vote
1answer
86 views
Numerical solution to approximate the singular integration using collocation method
I am working to solve "numerically" the following integral equation IE:
u[x]=f[x]+Integrate[(1/(x-t)^(1/4))*u[t],{t,0,x}]+Integrate[(1/(x-t)^(1/4))*u[t],{t,0,1}]
...
2
votes
3answers
140 views
2
votes
1answer
157 views
Computing FundamentalFrequency
How does Mathematica use AudioLocalMeasurements to compute the fundamental frequency?
Is there any formula? I can't seem to find what method Mathematica makes use ...
0
votes
0answers
29 views
Multifractality - Wolfram Code [duplicate]
In order to descrive the multifractal behaviour of a set, Baumann provides a code based on the functions Dq and Tau, given below.
...
2
votes
0answers
87 views
Coefficients of continuous wavelet transform
I am fiddling with wavelet coefficients in Mathematica, and for simplicty only
a real valued Wavlet.
Lets say we have the data:
...
0
votes
1answer
100 views
Getting errors NIntegrate::nlim and NIntegrate::slwcon [closed]
Here is the modified question:
First: Define
phi[x_]:=Piecewise[{{1, 0 <= x < 1}}, 0]
...
1
vote
0answers
85 views
Revert image fusion using discrete wavelet transform
How can I extract a hidden image using discrete wavelet transform? I have used the function ImageFusion from this site to hide an image inside another one.
...
20
votes
1answer
4k views
Extracting information from the result of ContinuousWaveletTransform
I'm trying to analysis a signal and identify some time-frequency information of it. For example, around which time the specific frequency arrives. It appears that Mathematica has very powerful wavelet ...
4
votes
2answers
148 views
How to extract a single image from the output of the DiscreteWaveletTransform[]?
So, I use the following code to carry out the discrete wavelet transform on an image of Lena. I am interested in then doing some changes to a single image out of the obtained 4. How do I extract any ...
1
vote
2answers
122 views
How to detect the singular value with wavelet analysis
I have a series data
data=Uncompress[
FromCharacterCode[Flatten[ImageData[Import["http://i.stack.imgur.com/ApipY.png"],
"Byte"]]]];
We can show it
...
1
vote
0answers
106 views
wavelet fourier transform
I want to do wavelet Fourier transform of my data but I have few doubts in this. 1)first of all what is octive and voice command here when i am changing value according to that my plot is changing but ...
1
vote
0answers
210 views
Comparison of Discrete Cosine Transform and Discrete Wavelet Transform
I would like to compare the sorted coefficients of the Discrete Cosine Transform with that of the Discrete Wavelet Transform using the Haar wavelets. From theory, the discrete wavelet transform offers ...
3
votes
1answer
188 views
Wavelet filter artifact
I would like to denoise some data using wavelet filters. My current approach is to employ the stationary wavelet transform with Haar wavelets.
However, this leads to undesirable artifacts at the top ...
3
votes
1answer
2k views
Wavelet vs instantaneous power spectrum
Following on from a previous question posted by @xslittlegrass and answered by @Sector and others, Extracting information from the result of ContinuousWaveletTransform I'd like to know if it is ...
3
votes
1answer
158 views
How to detect the singular value in 3-dimension with wavelet analysis
Actually this question is related with this post,but this is about point of 3-dimension
...
8
votes
2answers
294 views
How to detect discolorations in an image?
I'm evaluating the technical quality of an images and I'd like to scan it for defects from dirty sensors. Are there any filters to quickly detect a blob of discoloration? Here are a few examples:
24
votes
3answers
1k views
Detecting components in timeseries
I'm looking at this sequence of values:
I'd like to detect the points where the center of the time-series shifts (around x=1000 and x=2000). Many of the transforms and smoothing methods I have tried ...
6
votes
2answers
211 views
How to calculate the amount of offset about two list
You can get my data by this code
{data1, data2} = Uncompress[FromCharacterCode@
Flatten[ImageData[Import["https://i.stack.imgur.com/ShSMY.png"], "Byte"]]];
We ...
9
votes
1answer
3k views
Create “Ostagram” like Images using Wavelet Transforms
I am trying to make an "ostagram" like image using wavelet transforms and image keypoints.
See the following link: https://www.facebook.com/ostagram/
This is done using neural networks, which I at ...
1
vote
0answers
160 views
Find wavelet transform coefficients in L1 norm [closed]
For my masters task I have to perform a Haar wavelet transform using an L1 norm. But Mathematica's built-in wavelet library can work only with L2 norm space. I tried to do this:
...
4
votes
0answers
96 views
Why does Continuous Wavelet Transform have phase information at high frequencies?
I'm playing around with ContinuousWaveletTransform using a sine wave of a constant frequency:
...
6
votes
0answers
1k views
Wavelet Transform Modulus Maxima (WTMM) method
Has anyone already coded the Wavelet Transform Modulus Maxima (WTMM) method for computing the singular spectrum using multi fractal formalism in Mathematica?
The goal is to analyse 1D, 2D and 3D data....
2
votes
1answer
750 views
How to generate a Wavelet Matrix?
The Wavelet Matrix, also called the Haar matrix, is very useful. We can find some useful information in MathWorld on how to generate it, but this document is too hard for me. From my reading of the ...
2
votes
0answers
799 views
Detrending a time-series by means of Discrete Wavelet Transform
I plot a time-series for observation as you can see in the plot:
I tried to detrend the time series by 3 different approaches which are: 1) differences, 2) detrended fluctuation analysis, and 3) ...
0
votes
1answer
88 views
How to recover data from a DiscreteWaveletTransform with Battle Lemarie Wavelets?
The question is why can data be recovered perfectly from a discrete Wavelet Transform with a Haar Wavelet but not with some Battle Lemarie Wavelets?
A simple example with the HaarWavelet[]:
...
2
votes
0answers
67 views
Modified WaveletImagePlot
When performing Wavelet Transform
img = ExampleData[{"TestImage", "Lena"}];
dwd = DiscreteWaveletTransform[img, HaarWavelet[], 2]
WaveletImagePlot[dwd]
I get ...
2
votes
0answers
247 views
How to obtain amplitude and phase of tidal data using wavelets
I have a time series of tidal data for one month and success with identifying tidal characteristic such as
semidiurnal or diurnal
spring and neap position
power spectrum
However, I don't have ...
5
votes
1answer
119 views
InverseWaveletTransform not recreating the original image exactly
I am trying to do DWT steganography. I first obtain the DiscreteWaveletTransform of the image as follows
...
4
votes
2answers
403 views
How to define a new wavelet type?
I have a problem in understanding how to create my own wavelets in Mathematica's wavelet framework.
There is a tutorial.
I have read the tutorial, but I don’t understand what exactly is needed to ...
1
vote
0answers
211 views
Wavelet Data Visualization (modus and phase) ListPlot [closed]
Due to ContinuousWaveletTransform[...] I can obtain information about wavelet-coefficient for example
...
5
votes
3answers
3k views
How to increase Spectrogram resolution?
I have a time-domain signal that I want do a time-frequency analysis on it. When I tried the Spectrogram, I always get very low resolution.
For example:
I have a ...
1
vote
0answers
118 views
Problem with DiscreteWaveletTransform for DaubechiesWavelet
I am trying to use Mathematica's wavelet transform. In preparation I entered:
...
1
vote
2answers
101 views
InverseWaveletTransform of a list of rules
I want to extract coefficient images from a DiscreteWaveletTransform and replace them by modified images of the same dimensions.
However, when I use ...
Sjoerd C. de Vries
61.5k12 gold badges166 silver badges305 bronze badges
2
votes
1answer
153 views
How many arguments does a function require, and how to use that in `Manipulate`
The goal is to vary the order parameters in wavelet transforms in the Manipulate environment. The various transformations have arguments of different rank. For ...
8
votes
1answer
2k views
How to extract notes and chords from audio?
I have a 3-second recording of a guitar chord which you can safely download here. I'm trying to use Mathematica's wavelet features to find out the notes in the chord, at least the docs says that ...
2
votes
1answer
549 views
Wavelet transform of data with sliders
I saw a beautiful application of wavelets applied to a randomly created data series of about 500 data points. It used the Haar wavelet and had two sliders. The first slider allowed the user to view a ...
3
votes
1answer
370 views
Wavelet expansion of given function (as opposed to DWT of given data)
To illustrate, say I take the following function (the reason for the square root will be apparent soon)
...
2
votes
1answer
150 views
LiftingWaveletTransform with irregular grids
One of the properties mentioned in the literature about the lifting wavelet transform is that it can be applied on irregular meshes or grids (i.e. not equally spaced samples); but I don't seem to see ...
1
vote
1answer
157 views
Calculate support of given wavelet
I am calculating approximations using wavelets but outside the multi resolution analysis framework; particularly, I am not using the built-in wavelet transforms.
Still, I need to calculate ...
17
votes
3answers
591 views
Disentangling the data
An experiment yields a functional dependence on two variables $F(x,y)$, can be imagined as a 2D map. It is known that the function can be factored as follows $F(x,y)=fx(x) gy(y) +gx(x) fy(y)$. Given ...
6
votes
3answers
2k views
Signal processing by means of WaveletTransform
I updated my question to explain what I want.
I have the voltage-time curve from the real industial object. This curve was gotten from the digital oscilloscope:
As you can see it has hight-frequency ...
2
votes
0answers
212 views
Is there a relatively easy way to add the “Cone of Influence” to a waveletscalogram?
I am analyzing time series data using the ContinousWaveletTransform function and plotting the results with WaveletScalogram. I ...
1
vote
1answer
286 views
Is wavelet a Nonlinear transform, or Not? [closed]
Is wavelet a Nonlinear transform, or Not?
specifically, continuous wavelet transform with morlet function. I am studying behavior of a dynamic system, and it has nonlinear behaviour. can I employ ...
12
votes
1answer
562 views
Wavelet transform order problem
I have a signal that I'm trying to study its time-frequency features by continuous wavelet transform. By choosing different wavelet order, I get some differences in the results.
...
8
votes
1answer
3k views
Continuous wavelet transform with complex Morlet function
The complex Morlet function is defined as:
$$Ψ(t,f_c,f_b)= \frac{1}{\sqrt[]{ \pi f_{b} } }\exp(-t^2/f_b)\exp(\jmath 2πf_ct)$$
where $f_b$ and $f_c$ are two important parameters in modifying the ...
12
votes
3answers
819 views
WaveletScalogram in polar coordinates
For given dataset
data = Re[Zeta[1/2 + I Range[0, 100, 0.01]]];
It is nice that Mathematica can plot data in both Cartesian and Polar coordinates.
...
