I am high-pass filtering a matrix of data using Python 3.7 with scipy 1.6 (using signal.butter and signal.cheby2). When I plot the filtered data using imshow(), an undesired fringe behavior occurs on the left edge of the data (input data on the left, filtered data on the right):
Such fringe behavior becomes more visible as filter order increases and it is a problem for the signal processing pipeline because the filtered data is then binarized (filtered data on the left, binarized filtered data on the right):
The main issue is that in the binarized data, I get true signal mixed with the fringes from the filtering.
My doubts are: why is this behavior hapenning and is it possible to suppress it? how?
Additional details:
Code
sos = butter(order, wCutoff, 'hp', fs=defines.FS, output='sos')
filtered = sosfilt(sos, data)
