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WaveletMapIndexed [f,wd]

applies the function f to the arrays of coefficients and indices of a ContinuousWaveletData or DiscreteWaveletData object.

WaveletMapIndexed [f,dwd,wind]

applies f to the DiscreteWaveletData coefficients specified by wind.

WaveletMapIndexed [f,cwd,octvoc]

applies f to the ContinuousWaveletData coefficients specified by octvoc.

Details
Details and Options Details and Options
Examples  
Basic Examples  
Scope  
Basic Uses  
Coefficient Specification  
Data  
Applications  
Data Processing  
Image Processing  
Sound Processing  
Wavelet Thresholding  
Properties & Relations  
Possible Issues  
See Also
Related Guides
History
Cite this Page

WaveletMapIndexed [f,wd]

applies the function f to the arrays of coefficients and indices of a ContinuousWaveletData or DiscreteWaveletData object.

WaveletMapIndexed [f,dwd,wind]

applies f to the DiscreteWaveletData coefficients specified by wind.

WaveletMapIndexed [f,cwd,octvoc]

applies f to the ContinuousWaveletData coefficients specified by octvoc.

Details

Examples

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Basic Examples  (2)

Rescale all coefficients of a discrete wavelet transform by 20:

Normal gives the array of coefficients:

Compare with the unmodified coefficients:

Amplify the {1} coefficient of the stationary wavelet transform of an image:

The inverse wavelet transform gives an image with vertical edges sharpened:

Scope  (11)

Basic Uses  (3)

Apply an arbitrary function to all coefficients of a discrete wavelet transform:

Apply a symbolic function that also depends on the wavelet index for each coefficient vector:

WaveletMapIndexed operates on ContinuousWaveletData or DiscreteWaveletData :

The result is a wavelet data object of the same type:

The modified data can be used in other wavelet functions such as inverse wavelet transforms:

Coefficient Specification  (4)

Transform only specified coefficients in DiscreteWaveletData :

Apply a function to detail coefficients only, using the index pattern {___, 1}:

Apply a function to coarse coefficients only, using the index pattern {___, 0}:

Transform only specified coefficients in a ContinuousWaveletData :

Apply a function to coefficients in the first octave {1,_} only:

Apply a function to all coefficients except those in the second octave, first voice {2,1}:

The function f can depend on the wavelet index as its second argument:

Define a function with an arbitrary dependence on the wavelet index:

Apply the function to continuous wavelet transform coefficients:

Data  (4)

For list data, the coefficients supplied as the first argument of f are lists:

Apply a function that transforms lists:

For multidimensional data, the coefficients are arrays of the same depth:

Apply a function that transforms array coefficients of that depth:

For image data, the coefficients are supplied to f as Image objects:

The coefficients have the same number of channels as the original image:

Apply a function that transforms image coefficients:

For sound data, the coefficients are two-dimensional arrays:

Dimensions of one coefficient:

The two dimensions specify the channel number and the wavelet coefficients for that channel:

Apply a function that transforms two-channel data:

Reconstructed Sound data:

Applications  (7)

Data Processing  (2)

Coefficients with short indices correspond to small-scale structure in the data:

Zero all small-scale coefficients from the stationary wavelet transform of random data:

The inverse wavelet transform varies only on larger scales:

Perform a simple thresholding operation by removing low-amplitude wavelet coefficients:

Compare with the original data:

Image Processing  (3)

Blur an image by setting small-scale detail coefficients to zero:

Compare with the original image:

Sharpen an image by amplifying small-scale detail coefficients:

Compare with the original image:

Use a mask image to vary between blurring and sharpening across an image:

Compare with the original image:

Sound Processing  (1)

Apply a nonlinear function to wavelet coefficients for sound data:

Inverse transform to obtain a reconstructed sound object:

Wavelet Thresholding  (1)

Perform a wavelet-based shrinkage based on conditional mean:

Compute a discrete wavelet transform up to refinement level 6:

Compute the standard deviation for the finest detail coefficients:

Compute the standard deviation for all wavelet coefficients:

Assuming a Gaussian mixture model, variance can be estimated in the proportion to :

Shrinkage estimates of the signal coefficients are given by:

Use WaveletMapIndexed to map over detail coefficients:

Reconstruct thresholded signal coefficients:

Properties & Relations  (3)

MapIndexed [f,expr] applies f to the parts of any expression:

WaveletMapIndexed [f,wd] applies f to the coefficients in the wavelet data object wd:

WaveletMapIndexed [vMap[f,v],wd] applies f to each part of each coefficient:

MapIndexed gives the part specification as the second argument of f:

WaveletMapIndexed gives the wavelet index specification as the second argument of f:

WaveletMapIndexed transforms arrays of coefficients, giving a new DiscreteWaveletData :

Use Map and Normal [dwd] to transform coefficients into normal expressions:

Or use ReplaceAll (/.):

Possible Issues  (2)

The function f is always passed the index specification as its second argument:

Use a function that operates on its first argument only:

The function f should return an array or image of the same dimensions:

Listable functions return an array of the same dimensions:

Arithmetic operations such as multiplication are Listable :

Use Map for functions that are not Listable :

Wolfram Research (2010), WaveletMapIndexed, Wolfram Language function, https://reference.wolfram.com/language/ref/WaveletMapIndexed.html.

Text

Wolfram Research (2010), WaveletMapIndexed, Wolfram Language function, https://reference.wolfram.com/language/ref/WaveletMapIndexed.html.

CMS

Wolfram Language. 2010. "WaveletMapIndexed." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/WaveletMapIndexed.html.

APA

Wolfram Language. (2010). WaveletMapIndexed. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/WaveletMapIndexed.html

BibTeX

@misc{reference.wolfram_2025_waveletmapindexed, author="Wolfram Research", title="{WaveletMapIndexed}", year="2010", howpublished="\url{https://reference.wolfram.com/language/ref/WaveletMapIndexed.html}", note=[Accessed: 08-January-2026]}

BibLaTeX

@online{reference.wolfram_2025_waveletmapindexed, organization={Wolfram Research}, title={WaveletMapIndexed}, year={2010}, url={https://reference.wolfram.com/language/ref/WaveletMapIndexed.html}, note=[Accessed: 08-January-2026]}

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