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"""
This module provides downsampling functions for traces.
"""
from typing import cast
import numpy as np
from public import public
from scipy.signal import decimate
from .trace import Trace
@public
def downsample_average(trace: Trace, factor: int = 2) -> Trace:
"""
Downsample samples of `trace` by `factor` by averaging `factor` consecutive samples in
non-intersecting windows.
:param trace:
:param factor:
:return:
"""
resized = np.resize(
trace.samples, len(trace.samples) - (len(trace.samples) % factor)
)
result_samples = cast(
np.ndarray,
resized.reshape(-1, factor)
.mean(axis=1)
.astype(trace.samples.dtype, copy=False),
)
return trace.with_samples(result_samples)
@public
def downsample_pick(trace: Trace, factor: int = 2, offset: int = 0) -> Trace:
"""
Downsample samples of `trace` by `factor` by picking each `factor`-th sample, starting at `offset`.
:param trace:
:param factor:
:param offset:
:return:
"""
result_samples = trace.samples[offset::factor].copy()
return trace.with_samples(result_samples)
@public
def downsample_max(trace: Trace, factor: int = 2) -> Trace:
"""
Downsample samples of `trace` by `factor` by taking the maximum out of `factor` consecutive samples in
non-intersecting windows.
:param trace:
:param factor:
:return:
"""
resized = np.resize(
trace.samples, len(trace.samples) - (len(trace.samples) % factor)
)
result_samples = cast(
np.ndarray,
resized.reshape(-1, factor).max(axis=1).astype(trace.samples.dtype, copy=False),
)
return trace.with_samples(result_samples)
@public
def downsample_min(trace: Trace, factor: int = 2) -> Trace:
"""
Downsample samples of `trace` by `factor` by taking the minimum out of `factor` consecutive samples in
non-intersecting windows.
:param trace:
:param factor:
:return:
"""
resized = np.resize(
trace.samples, len(trace.samples) - (len(trace.samples) % factor)
)
result_samples = cast(
np.ndarray,
resized.reshape(-1, factor).min(axis=1).astype(trace.samples.dtype, copy=False),
)
return trace.with_samples(result_samples)
@public
def downsample_decimate(trace: Trace, factor: int = 2) -> Trace:
"""
Downsample samples of `trace` by `factor` by decimating.
:param trace:
:param factor:
:return:
"""
result_samples = decimate(trace.samples, factor)
return trace.with_samples(result_samples)
|
