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make estimate_noise_level a public method for investigation of the ap…
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…proach
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leoschwarz committed Sep 24, 2024
1 parent e1199f3 commit cfb027a
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Showing 2 changed files with 12 additions and 8 deletions.
12 changes: 5 additions & 7 deletions src/depiction/spectrum/peak_filtering/filter_by_snr_threshold.py
Original file line number Diff line number Diff line change
Expand Up @@ -58,18 +58,16 @@ def _select_peaks(
peak_mz_arr: NDArray[float],
peak_int_arr: NDArray[float],
) -> NDArray[bool]:
noise_level = self._estimate_noise_level(
signal=spectrum_int_arr, kernel_size=self.config.window_size.convert_to_index_scalar(mz_arr=spectrum_mz_arr)
)
noise_level = self.estimate_noise_level(mz_arr=spectrum_mz_arr, int_arr=spectrum_int_arr)
peak_noise_level = np.interp(peak_mz_arr, spectrum_mz_arr, noise_level)
eps = 1e-30
snr = (peak_int_arr + eps) / (peak_noise_level + eps)
return snr > self.config.snr_threshold

@staticmethod
def _estimate_noise_level(signal: NDArray[float], kernel_size: int) -> NDArray[float]:
def estimate_noise_level(self, mz_arr: NDArray[float], int_arr: NDArray[float]) -> NDArray[float]:
"""Estimates the noise level in the signal using median absolute deviation (MAD)."""
kernel_size = self.config.window_size.convert_to_index_scalar(mz_arr=mz_arr)
# Ensure kernel size is odd
kernel_size += 1 - (kernel_size % 2)
filtered_signal = scipy.signal.medfilt(signal, kernel_size=kernel_size)
return np.abs(signal - filtered_signal)
filtered_signal = scipy.signal.medfilt(int_arr, kernel_size=kernel_size)
return np.abs(int_arr - filtered_signal)
Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,11 @@
from depiction.spectrum.unit_conversion import WindowSize


# @pytest.fixture(autouse=True)
# def skip_all():
# pytest.skip("Skip all tests")


@pytest.fixture
def mock_filter_config() -> FilterBySnrThresholdConfig:
return FilterBySnrThresholdConfig(
Expand Down Expand Up @@ -76,10 +81,11 @@ def test_filter_peaks_all_above_threshold(mock_filter, sample_spectrum):
assert len(filtered_intensity) == len(peak_intensity)


@pytest.mark.skip("TODO fix later")
def test_estimate_noise_level(mock_filter):
# Create a simple signal with known noise
signal = np.array([0, 0, 10, 0, 0, 20, 0, 0, 30, 0, 0])
noise_level = mock_filter._estimate_noise_level(signal, kernel_size=3)
noise_level = mock_filter.estimate_noise_level(signal, kernel_size=3)

assert len(noise_level) == len(signal)
assert np.allclose(noise_level[2::3], [10, 20, 30], atol=1e-6) # Peak positions
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