Event

MDAEvent

Define a single event in a MDASequence.

Usually, this object will be generator by iterating over a MDASequence (see useq.MDASequence.iter_events).

Attributes:

Name	Type	Description
index	dict[str, int]	Index of this event in the sequence. This is a mapping of axis name to index. For example: {'t': 4, 'c': 0, 'z': 5},
channel	Channel | None	Channel to use for this event. If None, implies use current channel. By default, None. Channel is a simple pydantic object with two attributes: config and group. config is the name of the configuration to use for this channel, (e.g. "488nm", "DAPI", "FITC"). group is the name of the group to which this channel belongs. By default, "Channel".
exposure	float | None	Exposure time in milliseconds. If not provided, implies use current exposure time. By default, None.
min_start_time	float | None	Minimum start time of this event, in seconds. If provided, the engine will pause until this time has elapsed (relative to the start of the sequence) before starting this event. By default, None.
pos_name	str | None	The name assigned to the position. By default, None.
x_pos	float | None	X position in microns. If not provided, implies use current position. By default, None.
y_pos	float | None	Y position in microns. If not provided, implies use current position. By default, None.
z_pos	float | None	Z position in microns. If not provided, implies use current position. By default, None.
sequence	MDASequence | None	A reference to the useq.MDASequence this event belongs to. This is a read-only attribute. By default, None.
properties	Sequence[PropertyTuple] | None	List of useq.PropertyTuple to set before starting this event. Where each item in the list is a 3-member named tuple of (device_name, property_name, property_value). This is inspired by micro-manager's Device Adapter API, but could be used to set arbitrary properties in any backend that supports the concept of devices that have properties with values. By default, None.
metadata	dict	Optional metadata to be associated with this event.
action	Action	The action to perform for this event. By default, useq.AcquireImage. Example of another action is useq.HardwareAutofocus which could be used to perform a hardware autofocus.
keep_shutter_open	bool	If True, the illumination shutter should be left open after the event has been executed, otherwise it should be closed. By default, False." This is useful when the sequence of events being executed use the same illumination scheme (such as a z-stack in a single channel), and closing and opening the shutter between events would be slow.

Channel

Channel in a MDA event.

Attributes:

Name	Type	Description
config	str	Name of the configuration to use for this channel, (e.g. "488nm", "DAPI", "FITC").
group	str	Optional name of the group to which this channel belongs. By default, "Channel".

PropertyTuple

Three-tuple capturing a device, property, and value.

Attributes:

Name	Type	Description
device_name	str	Name of a device.
property_name	str	Name of a property recognized by the device.
value	Any	Value for the property.

Event Actions

Action

Base class for a useq.MDAEvent action.

An Action specifies what task should be performed during a useq.MDAEvent. An Action can be for example used to acquire an image (useq.AcquireImage) or to perform a hardware autofocus (useq.HardwareAutofocus).

Attributes:

Name	Type	Description
type	str	Type of the action that should be performed at the useq.MDAEvent.

AcquireImage

useq.Action to acquire an image.

Attributes:

Name	Type	Description
type	Literal['acquire_image']	This action can be used to acquire an image.

HardwareAutofocus

useq.Action to perform a hardware autofocus.

See also useq.AutoFocusPlan.

Attributes:

Name	Type	Description
type	Literal['hardware_autofocus']	This action can be used to trigger hardware autofocus.
autofocus_device_name	(str, optional)	The name of the autofocus offset motor device (if applicable). If None, acquisition engines may attempt to set the offset however they see fit (such as using a current or default autofocus device.)
autofocus_motor_offset	(float, optional)	Before autofocus is performed, the autofocus motor should be moved to this offset, if applicable. (Not all autofocus devices have an offset motor.) If None, the autofocus motor should not be moved.
max_retries	int	The number of retries if autofocus fails. By default, 3.