From 513526ae310230b5ebb1b6c895f747ff94526c31 Mon Sep 17 00:00:00 2001
From: Peter Swain <pswain@Home-iMac.local>
Date: Wed, 24 Apr 2024 15:59:00 +0100
Subject: [PATCH] feature: added Arin's butterfilter
---
butterfilter.py | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
create mode 100644 butterfilter.py
diff --git a/butterfilter.py b/butterfilter.py
new file mode 100644
index 0000000..557b1fd
--- /dev/null
+++ b/butterfilter.py
@@ -0,0 +1,28 @@
+import numpy as np
+from scipy import signal
+
+
+def butterfilter(timeseries, params=None):
+ """Apply Butterworth filter to time series arranged in rows."""
+ # second-order-sections output
+ # by default, using a digital filter
+ if params is None:
+ params = {
+ "order": 2,
+ "critical_freqs": (1 / 350),
+ "filter_type": "highpass",
+ "sampling_freq": 1 / 3,
+ }
+ sos = signal.butter(
+ N=params["order"],
+ Wn=params["critical_freqs"],
+ btype=params["filter_type"],
+ fs=params["sampling_freq"],
+ output="sos",
+ )
+ # subtract time series by mean
+ timeseries_norm = timeseries - np.nanmean(timeseries, axis=1).reshape(
+ timeseries.shape[0], 1
+ )
+ filtered_timeseries = signal.sosfiltfilt(sos, timeseries_norm, axis=1)
+ return filtered_timeseries
--
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