filters
- LTI filters for bivariate signals¶
Unitary Filter¶
- class bispy.filters.UnitaryFilter(N, mu, alpha, phi, dt=1.0)[source]¶
Unitary filter for bivariate signals. The Unitary filtering relation reads in the QFT spectral domain:
Y(nu) = exp(mu(nu)*alpha(nu) / 2)*X(nu)exp(1j*phi(nu))
where phi is phase delay of the filter, mu its axis and alpha is the birefringence angle.
- Parameters:
- Nint
length of the filter
- muarray_type (quaternion)
birefringence axis quaternion array (should be of size N and of dtype quaternion).
- alphaarray_type
birefringence angle array (should be of size N). If alpha is a float, then alpha is assumed constant throughout frequencies.
- phiarray_type or float
phase delay array (should be of size N). If phi is a float, then a constant phase delay is assumed throughout frequencies.
- dtfloat (optional)
time sampling step (default 1)
- Attributes:
- Nint
length of the filter
- farray_type
sampled frequencies
- dtfloat
time sampling step (default 1)
- mu, alpha, phiarray_types
filter parameters
Methods
output
(x)returns the output of the filter given an input signal x
HermitianFilter¶
- class bispy.filters.HermitianFilter(N, K, eta, mu, dt=1.0)[source]¶
Hermitian filter for bivariate signals. The Hermitian filtering relations reads in the QFT spectral domain:
Y(nu) = K(nu)*[X(nu) - eta(nu)*mu(nu)*X(nu)*qj]
where K is the homogeneous gain of the filter, eta is the polarizing power and mu the axis of the filter.
- Parameters:
- Nint
length of the filter
- Karray_type or float
homogeneous gain array (should be of size N). If K is a float, then a constant gain is assumed throughout frequencies.
- etaarray_type or float
polarizing power array (should be of size N). If eta is a float, then a constant polarizing is assumed throughout frequencies.
- muarray_type (quaternion) or quaternion
diattenuation axis quaternion array (should be of size N and of dtype quaternion).
- dtfloat (optional)
time sampling step (default 1)
- Attributes:
- Nint
length of the filter
- farray_type
sampled frequencies
- dtfloat
time sampling step (default 1)
- K, eta, muarray_types
filter parameters
Methods
output
(x)returns the output of the filter given an input signal x