Signal processing (scipy.signal)¶
Convolution¶
convolve(in1, in2[, mode]) | Convolve two N-dimensional arrays. |
correlate(in1, in2[, mode]) | Cross-correlate two N-dimensional arrays. |
fftconvolve(in1, in2[, mode]) | Convolve two N-dimensional arrays using FFT. |
convolve2d(in1, in2[, mode, boundary, fillvalue]) | Convolve two 2-dimensional arrays. |
correlate2d(in1, in2[, mode, boundary, ...]) | Cross-correlate two 2-dimensional arrays. |
sepfir2d((input, hrow, hcol) -> output) | Description: Convolve the rank-2 input array with the separable filter defined by the rank-1 arrays hrow, and hcol. |
B-splines¶
bspline(x, n) | B-spline basis function of order n. |
cubic(x) | A cubic B-spline. |
quadratic(x) | A quadratic B-spline. |
gauss_spline(x, n) | Gaussian approximation to B-spline basis function of order n. |
cspline1d(signal[, lamb]) | Compute cubic spline coefficients for rank-1 array. |
qspline1d(signal[, lamb]) | Compute quadratic spline coefficients for rank-1 array. |
cspline2d((input {, lambda, precision}) -> ck) | Description: Return the third-order B-spline coefficients over a regularly spacedi input grid for the two-dimensional input image. |
qspline2d((input {, lambda, precision}) -> qk) | Description: Return the second-order B-spline coefficients over a regularly spaced input grid for the two-dimensional input image. |
cspline1d_eval(cj, newx[, dx, x0]) | Evaluate a spline at the new set of points. |
qspline1d_eval(cj, newx[, dx, x0]) | Evaluate a quadratic spline at the new set of points. |
spline_filter(Iin[, lmbda]) | Smoothing spline (cubic) filtering of a rank-2 array. |
Filtering¶
order_filter(a, domain, rank) | Perform an order filter on an N-dimensional array. |
medfilt(volume[, kernel_size]) | Perform a median filter on an N-dimensional array. |
medfilt2d(input[, kernel_size]) | Median filter a 2-dimensional array. |
wiener(im[, mysize, noise]) | Perform a Wiener filter on an N-dimensional array. |
symiirorder1((input, c0, z1 {, ...) | Implement a smoothing IIR filter with mirror-symmetric boundary conditions using a cascade of first-order sections. |
symiirorder2((input, r, omega {, ...) | Implement a smoothing IIR filter with mirror-symmetric boundary conditions using a cascade of second-order sections. |
lfilter(b, a, x[, axis, zi]) | Filter data along one-dimension with an IIR or FIR filter. |
lfiltic(b, a, y[, x]) | Construct initial conditions for lfilter. |
lfilter_zi(b, a) | Compute an initial state zi for the lfilter function that corresponds to the steady state of the step response. |
filtfilt(b, a, x[, axis, padtype, padlen, ...]) | A forward-backward filter. |
savgol_filter(x, window_length, polyorder[, ...]) | Apply a Savitzky-Golay filter to an array. |
deconvolve(signal, divisor) | Deconvolves divisor out of signal. |
sosfilt(sos, x[, axis, zi]) | Filter data along one dimension using cascaded second-order sections Filter a data sequence, x, using a digital IIR filter defined by sos. |
sosfilt_zi(sos) | Compute an initial state zi for the sosfilt function that corresponds to the steady state of the step response. |
hilbert(x[, N, axis]) | Compute the analytic signal, using the Hilbert transform. |
hilbert2(x[, N]) | Compute the ‘2-D’ analytic signal of x :Parameters: x : array_like 2-D signal data. |
decimate(x, q[, n, ftype, axis]) | Downsample the signal by using a filter. |
detrend(data[, axis, type, bp]) | Remove linear trend along axis from data. |
resample(x, num[, t, axis, window]) | Resample x to num samples using Fourier method along the given axis. |
Filter design¶
bilinear(b, a[, fs]) | Return a digital filter from an analog one using a bilinear transform. |
findfreqs(num, den, N) | Find an array of frequencies for computing the response of a filter. |
firwin(numtaps, cutoff[, width, window, ...]) | FIR filter design using the window method. |
firwin2(numtaps, freq, gain[, nfreqs, ...]) | FIR filter design using the window method. |
freqs(b, a[, worN, plot]) | Compute frequency response of analog filter. |
freqz(b[, a, worN, whole, plot]) | Compute the frequency response of a digital filter. |
group_delay(system[, w, whole]) | Compute the group delay of a digital filter. |
iirdesign(wp, ws, gpass, gstop[, analog, ...]) | Complete IIR digital and analog filter design. |
iirfilter(N, Wn[, rp, rs, btype, analog, ...]) | IIR digital and analog filter design given order and critical points. |
kaiser_atten(numtaps, width) | Compute the attenuation of a Kaiser FIR filter. |
kaiser_beta(a) | Compute the Kaiser parameter beta, given the attenuation a. |
kaiserord(ripple, width) | Design a Kaiser window to limit ripple and width of transition region. |
savgol_coeffs(window_length, polyorder[, ...]) | Compute the coefficients for a 1-d Savitzky-Golay FIR filter. |
remez(numtaps, bands, desired[, weight, Hz, ...]) | Calculate the minimax optimal filter using the Remez exchange algorithm. |
unique_roots(p[, tol, rtype]) | Determine unique roots and their multiplicities from a list of roots. |
residue(b, a[, tol, rtype]) | Compute partial-fraction expansion of b(s) / a(s). |
residuez(b, a[, tol, rtype]) | Compute partial-fraction expansion of b(z) / a(z). |
invres(r, p, k[, tol, rtype]) | Compute b(s) and a(s) from partial fraction expansion. |
invresz(r, p, k[, tol, rtype]) | Compute b(z) and a(z) from partial fraction expansion. |
BadCoefficients | Warning about badly conditioned filter coefficients |
Lower-level filter design functions:
abcd_normalize([A, B, C, D]) | Check state-space matrices and ensure they are two-dimensional. |
band_stop_obj(wp, ind, passb, stopb, gpass, ...) | Band Stop Objective Function for order minimization. |
besselap(N) | Return (z,p,k) for analog prototype of an Nth order Bessel filter. |
buttap(N) | Return (z,p,k) for analog prototype of Nth order Butterworth filter. |
cheb1ap(N, rp) | Return (z,p,k) for Nth order Chebyshev type I analog lowpass filter. |
cheb2ap(N, rs) | Return (z,p,k) for Nth order Chebyshev type I analog lowpass filter. |
cmplx_sort(p) | Sort roots based on magnitude. |
ellipap(N, rp, rs) | Return (z,p,k) of Nth order elliptic analog lowpass filter. |
lp2bp(b, a[, wo, bw]) | Transform a lowpass filter prototype to a bandpass filter. |
lp2bs(b, a[, wo, bw]) | Transform a lowpass filter prototype to a bandstop filter. |
lp2hp(b, a[, wo]) | Transform a lowpass filter prototype to a highpass filter. |
lp2lp(b, a[, wo]) | Transform a lowpass filter prototype to a different frequency. |
normalize(b, a) | Normalize polynomial representation of a transfer function. |
Matlab-style IIR filter design¶
butter(N, Wn[, btype, analog, output]) | Butterworth digital and analog filter design. |
buttord(wp, ws, gpass, gstop[, analog]) | Butterworth filter order selection. |
cheby1(N, rp, Wn[, btype, analog, output]) | Chebyshev type I digital and analog filter design. |
cheb1ord(wp, ws, gpass, gstop[, analog]) | Chebyshev type I filter order selection. |
cheby2(N, rs, Wn[, btype, analog, output]) | Chebyshev type II digital and analog filter design. |
cheb2ord(wp, ws, gpass, gstop[, analog]) | Chebyshev type II filter order selection. |
ellip(N, rp, rs, Wn[, btype, analog, output]) | Elliptic (Cauer) digital and analog filter design. |
ellipord(wp, ws, gpass, gstop[, analog]) | Elliptic (Cauer) filter order selection. |
bessel(N, Wn[, btype, analog, output]) | Bessel/Thomson digital and analog filter design. |
Continuous-Time Linear Systems¶
freqresp(system[, w, n]) | Calculate the frequency response of a continuous-time system. |
lti(*system) | Linear Time Invariant system base class. |
StateSpace(*system) | Linear Time Invariant system class in state-space form. |
TransferFunction(*system) | Linear Time Invariant system class in transfer function form. |
ZerosPolesGain(*system) | Linear Time Invariant system class in zeros, poles, gain form. |
lsim(system, U, T[, X0, interp]) | Simulate output of a continuous-time linear system. |
lsim2(system[, U, T, X0]) | Simulate output of a continuous-time linear system, by using the ODE solver scipy.integrate.odeint. |
impulse(system[, X0, T, N]) | Impulse response of continuous-time system. |
impulse2(system[, X0, T, N]) | Impulse response of a single-input, continuous-time linear system. |
step(system[, X0, T, N]) | Step response of continuous-time system. |
step2(system[, X0, T, N]) | Step response of continuous-time system. |
bode(system[, w, n]) | Calculate Bode magnitude and phase data of a continuous-time system. |
Discrete-Time Linear Systems¶
dlsim(system, u[, t, x0]) | Simulate output of a discrete-time linear system. |
dimpulse(system[, x0, t, n]) | Impulse response of discrete-time system. |
dstep(system[, x0, t, n]) | Step response of discrete-time system. |
LTI Representations¶
tf2zpk(b, a) | Return zero, pole, gain (z, p, k) representation from a numerator, denominator representation of a linear filter. |
tf2sos(b, a[, pairing]) | Return second-order sections from transfer function representation :Parameters: b : array_like Numerator polynomial coefficients. |
tf2ss(num, den) | Transfer function to state-space representation. |
zpk2tf(z, p, k) | Return polynomial transfer function representation from zeros and poles :Parameters: z : array_like Zeros of the transfer function. |
zpk2sos(z, p, k[, pairing]) | Return second-order sections from zeros, poles, and gain of a system :Parameters: z : array_like Zeros of the transfer function. |
zpk2ss(z, p, k) | Zero-pole-gain representation to state-space representation :Parameters: z, p : sequence Zeros and poles. |
ss2tf(A, B, C, D[, input]) | State-space to transfer function. |
ss2zpk(A, B, C, D[, input]) | State-space representation to zero-pole-gain representation. |
sos2zpk(sos) | Return zeros, poles, and gain of a series of second-order sections :Parameters: sos : array_like Array of second-order filter coefficients, must have shape (n_sections, 6). |
sos2tf(sos) | Return a single transfer function from a series of second-order sections :Parameters: sos : array_like Array of second-order filter coefficients, must have shape (n_sections, 6). |
cont2discrete(sys, dt[, method, alpha]) | Transform a continuous to a discrete state-space system. |
place_poles(A, B, poles[, method, rtol, maxiter]) | Compute K such that eigenvalues (A - dot(B, K))=poles. |
Waveforms¶
chirp(t, f0, t1, f1[, method, phi, vertex_zero]) | Frequency-swept cosine generator. |
gausspulse(t[, fc, bw, bwr, tpr, retquad, ...]) | Return a Gaussian modulated sinusoid: exp(-a t^2) exp(1j*2*pi*fc*t). If retquad is True, then return the real and imaginary parts (in-phase and quadrature). |
max_len_seq(nbits[, state, length, taps]) | Maximum length sequence (MLS) generator. |
sawtooth(t[, width]) | Return a periodic sawtooth or triangle waveform. |
square(t[, duty]) | Return a periodic square-wave waveform. |
sweep_poly(t, poly[, phi]) | Frequency-swept cosine generator, with a time-dependent frequency. |
Window functions¶
get_window(window, Nx[, fftbins]) | Return a window. |
barthann(M[, sym]) | Return a modified Bartlett-Hann window. |
bartlett(M[, sym]) | Return a Bartlett window. |
blackman(M[, sym]) | Return a Blackman window. |
blackmanharris(M[, sym]) | Return a minimum 4-term Blackman-Harris window. |
bohman(M[, sym]) | Return a Bohman window. |
boxcar(M[, sym]) | Return a boxcar or rectangular window. |
chebwin(M, at[, sym]) | Return a Dolph-Chebyshev window. |
cosine(M[, sym]) | Return a window with a simple cosine shape. |
exponential(M[, center, tau, sym]) | Return an exponential (or Poisson) window. |
flattop(M[, sym]) | Return a flat top window. |
gaussian(M, std[, sym]) | Return a Gaussian window. |
general_gaussian(M, p, sig[, sym]) | Return a window with a generalized Gaussian shape. |
hamming(M[, sym]) | Return a Hamming window. |
hann(M[, sym]) | Return a Hann window. |
hanning(M[, sym]) | Return a Hann window. |
kaiser(M, beta[, sym]) | Return a Kaiser window. |
nuttall(M[, sym]) | Return a minimum 4-term Blackman-Harris window according to Nuttall. |
parzen(M[, sym]) | Return a Parzen window. |
slepian(M, width[, sym]) | Return a digital Slepian (DPSS) window. |
triang(M[, sym]) | Return a triangular window. |
tukey(M[, alpha, sym]) | Return a Tukey window, also known as a tapered cosine window. |
Wavelets¶
cascade(hk[, J]) | Return (x, phi, psi) at dyadic points K/2**J from filter coefficients. |
daub(p) | The coefficients for the FIR low-pass filter producing Daubechies wavelets. |
morlet(M[, w, s, complete]) | Complex Morlet wavelet. |
qmf(hk) | Return high-pass qmf filter from low-pass :Parameters: hk : array_like Coefficients of high-pass filter. |
ricker(points, a) | Return a Ricker wavelet, also known as the “Mexican hat wavelet”. |
cwt(data, wavelet, widths) | Continuous wavelet transform. |
Peak finding¶
find_peaks_cwt(vector, widths[, wavelet, ...]) | Attempt to find the peaks in a 1-D array. |
argrelmin(data[, axis, order, mode]) | Calculate the relative minima of data. |
argrelmax(data[, axis, order, mode]) | Calculate the relative maxima of data. |
argrelextrema(data, comparator[, axis, ...]) | Calculate the relative extrema of data. |
Spectral Analysis¶
periodogram(x[, fs, window, nfft, detrend, ...]) | Estimate power spectral density using a periodogram. |
welch(x[, fs, window, nperseg, noverlap, ...]) | Estimate power spectral density using Welch’s method. |
csd(x, y[, fs, window, nperseg, noverlap, ...]) | Estimate the cross power spectral density, Pxy, using Welch’s method. |
coherence(x, y[, fs, window, nperseg, ...]) | Estimate the magnitude squared coherence estimate, Cxy, of discrete-time signals X and Y using Welch’s method. |
spectrogram(x[, fs, window, nperseg, ...]) | Compute a spectrogram with consecutive Fourier transforms. |
lombscargle(x, y, freqs) | Computes the Lomb-Scargle periodogram. |
vectorstrength(events, period) | Determine the vector strength of the events corresponding to the given period. |