Other functions¶
Single-level n-dimensional Discrete Wavelet Transform.¶
-
pywt.
dwtn
(data, wavelet[, mode='sym'])¶ Performs single-level n-dimensional Discrete Wavelet Transform.
Parameters: - data – n-dimensional array
- wavelet – Wavelet to use in the transform. This can be a name of the wavelet from the
wavelist()
list or aWavelet
object instance. - mode – Signal extension mode to deal with the border distortion problem. See MODES for details.
Results are arranged in a dictionary, where key specifies the transform type on each dimension and value is a n-dimensional coefficients array.
For example, for a 2D case the result will look something like this:
{ 'aa': <coeffs> # A(LL) - approx. on 1st dim, approx. on 2nd dim 'ad': <coeffs> # H(LH) - approx. on 1st dim, det. on 2nd dim 'da': <coeffs> # V(HL) - det. on 1st dim, approx. on 2nd dim 'dd': <coeffs> # D(HH) - det. on 1st dim, det. on 2nd dim }
Integrating wavelet functions - intwave()
¶
-
pywt.
intwave
(wavelet[, precision=8])¶ Integration of wavelet function approximations as well as any other signals can be performed using the
pywt.intwave()
function.The result of the call depends on the wavelet argument:
for orthogonal wavelets - an integral of the wavelet function specified on an x-grid:
[int_psi, x] = intwave(wavelet, precision)
for other wavelets - integrals of decomposition and reconstruction wavelet functions and a corresponding x-grid:
[int_psi_d, int_psi_r, x] = intwave(wavelet, precision)
for a tuple of coefficients data and a x-grid - an integral of function and the given x-grid is returned (the x-grid is used for computations).:
[int_function, x] = intwave((data, x), precision)
Example:
>>> import pywt >>> wavelet1 = pywt.Wavelet('db2') >>> [int_psi, x] = pywt.intwave(wavelet1, precision=5) >>> wavelet2 = pywt.Wavelet('bior1.3') >>> [int_psi_d, int_psi_r, x] = pywt.intwave(wavelet2, precision=5)
Central frequency of psi wavelet function¶
-
pywt.
centfrq
(wavelet[, precision=8])¶ -
pywt.
centfrq
((function_approx, x)) Parameters: - wavelet –
Wavelet
, wavelet name string or (wavelet function approx., x grid) pair - precision – Precision that will be used for wavelet function
approximation computed with the
Wavelet.wavefun()
method.
- wavelet –