PyWavelets Documentation

PyWavelets Documentation

Release 1.3.0.dev0+9a72143 The PyWavelets Developers

Dec 14, 2021

1 Main features 2 Getting help 3 License 4 Citing 5 Contents Bibliography Index

Contents

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PyWavelets Documentation, Release 1.3.0.dev0+9a72143

PyWavelets is open source wavelet transform software for Python. It combines a simple high level interface with low level C and Cython performance. PyWavelets is very easy to use and get started with. Just install the package, open the Python interactive shell and type:

>>> import pywt >>> cA, cD = pywt.dwt([1, 2, 3, 4], 'db1')

Voil?! Computing wavelet transforms has never been so simple :) Here is a slightly more involved example of applying a digital wavelet transform to an image:

import numpy as np import matplotlib.pyplot as plt

import pywt import pywt.data

# Load image original = pywt.data.camera()

# Wavelet transform of image, and plot approximation and details titles = ['Approximation', ' Horizontal detail',

'Vertical detail', 'Diagonal detail'] coeffs2 = pywt.dwt2(original, 'bior1.3') LL, (LH, HL, HH) = coeffs2 fig = plt.figure(figsize=(12, 3)) for i, a in enumerate([LL, LH, HL, HH]):

ax = fig.add_subplot(1, 4, i + 1) ax.imshow(a, interpolation="nearest", cmap=plt.cm.gray) ax.set_title(titles[i], fontsize=10) ax.set_xticks([]) ax.set_yticks([])

fig.tight_layout() plt.show()

Approximation

Horizontal detail

Vertical detail

Diagonal detail

Contents

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Contents

1 CHAPTER

Main features

The main features of PyWavelets are: ? 1D, 2D and nD Forward and Inverse Discrete Wavelet Transform (DWT and IDWT) ? 1D, 2D and nD Multilevel DWT and IDWT ? 1D, 2D and nD Stationary Wavelet Transform (Undecimated Wavelet Transform) ? 1D and 2D Wavelet Packet decomposition and reconstruction ? 1D Continuous Wavelet Transform ? Computing Approximations of wavelet and scaling functions ? Over 100 built-in wavelet filters and support for custom wavelets ? Single and double precision calculations ? Real and complex calculations ? Results compatible with Matlab Wavelet Toolbox (TM)

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Chapter 1. Main features

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