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ZCAwhiten

zca whiten of an image


Description

this function performs zca-whitening to a 2- or 3- dimensional image

Usage

ZCAwhiten(image, k, epsilon)

Arguments

image

a matrix, data frame or 3-dimensional array

k

an integer specifying the number of components to keep when svd is performed (reduced dimension representation of the data)

epsilon

a float specifying the regularization parameter

Details

Whitening (or sphering) is the preprocessing needed for some algorithms. If we are training on images, the raw input is redundant, since adjacent pixel values are highly correlated. When using whitening the features become less correlated and all features have the same variance.

Value

a matrix or 3-dimensional array

References

http://ufldl.stanford.edu/wiki/index.php/Whitening

Examples

path = system.file("tmp_images", "1.png", package = "OpenImageR")

image = readImage(path)

res = ZCAwhiten(image, k = 20, epsilon = 0.1)

OpenImageR

An Image Processing Toolkit

v1.1.8
GPL-3
Authors
Lampros Mouselimis [aut, cre] (<https://orcid.org/0000-0002-8024-1546>), Sight Machine [cph] (findHOGFeatures function of the SimpleCV computer vision platform), Johannes Buchner [cph] (average_hash, dhash and phash functions of the ImageHash python library), Mohammad Haghighat [cph] (Gabor Feature Extraction), Radhakrishna Achanta [cph] (Author of the C++ code of the SLIC and SLICO algorithms (for commercial use please contact the author))
Initial release
2021-05-04

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