meeg_utils.qc.ChpiSNR

class meeg_utils.qc.ChpiSNR(*, max_drop_db=None)

Signal-to-noise ratio of the continuous head-position (cHPI) coils.

mne.chpi.compute_chpi_snr() estimates, over time, the power of each coil’s frequency relative to the residual. A coil much weaker than the others is loose, badly placed or broken, and head positions computed from it are unreliable.

Parameters:

max_drop_db (float | None) – A coil whose median SNR is this much below the median over coils is flagged. There is no published limit (coils differ with their distance to the sensors, so some spread is normal); None (default) reports each coil’s drop without a verdict. 10 dB (a tenth of the power) is a reasonable starting point.

metrics_

Per channel type (mag/grad): median SNR per coil (dB) and the coil frequencies.

Type:

dict

Notes

Figures: "snr" (mne.viz.plot_chpi_snr()).

__init__(*, max_drop_db=None)

Methods

__init__(*[, max_drop_db])
compute(raw)	Measure the recording.
get_metadata_routing()	Get metadata routing of this object.
get_params([deep])	Get parameters for this estimator.
not_applicable(raw)	Return why the check cannot run on raw, or None if it can.
plot([kind, inst])	Draw quality-control figures.
set_params(**params)	Set the parameters of this estimator.

Attributes

level	The worst verdict of the findings ("ok" if there are none).
modalities	Data types the check needs at least one of ("meg", "eeg").
name	Key of the check in reports.
plot_kinds	kind -> whether it needs data (inst).
systems	Acquisition systems the check applies to; None means all.

name: ClassVar[str] = 'chpi_snr'

Key of the check in reports.

modalities: ClassVar[frozenset[str]] = frozenset({'meg'})

Data types the check needs at least one of (“meg”, “eeg”).

systems: ClassVar[frozenset[str] | None] = frozenset({'neuromag'})

Acquisition systems the check applies to; None means all.

plot_kinds: ClassVar[dict[str, bool]] = {'snr': False}

kind -> whether it needs data (inst). Each kind is drawn by a _plot_<kind>(inst, **kwargs) method.

Type:

Figures the object can draw once fitted

not_applicable(raw)

Return why the check cannot run on raw, or None if it can.

Parameters:

raw (Raw) – The recording.

Returns:

The reason, or None.

Return type:

str | None