ChannelLabeler

class gpype.backend.flow.channel_labeler.ChannelLabeler

Bases: IONode

Says what each channel is, without touching the data.

Only some sources can name their own channels, and none of them can know what a user has wired downstream. Without names a recording lands as Ch01..ChNN and a stream goes out unnamed, which is a problem on analysis day rather than on recording day.

It also carries roles, which say how a channel must be treated rather than what it is. Marking the extra channels an amplifier appends – a digital input as a trigger, an accelerometer as auxiliary, a link quality as quality – is what stops a filter from smearing them.

And it carries units: the other route a stream’s physical unit reaches the context by, beside an amplifier source declaring its own. A Generator, a foreign LSL stream, or an amplifier this package does not yet cover can be told what it measures, and units given here override whatever the input already declared – the author is asserting ground truth, not merely filling a gap.

The data passes through untouched; only the description changes.

AT_MOST_ONE_OF = (('montage', 'labels'),)

At most one of these – “Give either a montage or labels, not both”. Distinct from ONE_OF: both may be absent, so this is not a requirement, only an exclusion.

class Configuration

Bases: Configuration

Configuration class for ChannelLabeler parameters.

class Keys

Bases: Keys

Configuration keys for ChannelLabeler settings.

class OptionalKeys

Bases: OptionalKeys

Optional configuration keys.

LABELS = 'labels'

Electrode labels, one per channel

ROLES = 'roles'

Per-channel roles, one per channel

SYSTEM = 'system'

Electrode system the labels come from

UNITS = 'units'

Physical unit, one per channel

__init__(labels=None, roles=None, montage=None, units=None, **kwargs)

Initialize the channel labeler.

Parameters:

• labels (Optional[list]) – One name per channel, e.g. ["C3", "Cz", "C4"].

• roles (Optional[list]) – One role per channel, from Constants.ChannelRoles. Channels left unnamed here count as measured signal.

• montage (Optional[Montage]) – A Montage to take the labels from, as an alternative to passing them directly.

• units (Optional[list]) – One physical unit per channel, e.g. ["uV", "uV"]; None for a channel with none. Overrides whatever the input already declared, rather than only filling a gap.

• **kwargs – Additional arguments for the parent IONode.

Raises:

ValueError – If both a montage and labels are given, if any list is empty, or if a role is not a known role.

setup(data, port_context_in)

Attach the description to the output context.

Parameters:

• data (dict[str, ndarray]) – Initial data dictionary.

• port_context_in (dict[str, dict]) – Input port contexts.

Return type:

dict[str, dict]

Returns:

Output port contexts carrying the description.

Raises:

ValueError – If a supplied list does not match the channel count, which would describe channels that do not exist.

step(data)

Pass the frame through unchanged.

Parameters:

data (dict[str, ndarray]) – Input frame.

Return type:

dict[str, ndarray]

Returns:

The same frame on the output port.