discover_tracking module

class discover_tracking.Tracker(subscribe=True, callback=None)

Bases: object

Methods

get_marker_distance()	A function that returns the distance that the marker is from the camera .
get_marker_id()	A function that returns the ID of the ARTag marker.
get_marker_visible()	A function that returns the value of the marker_visible flag.
subscribe_to_marker_topic()	Subscribes to ROS /visualization_marker topic published by the alavar tracking node.

get_marker_distance() → float

A function that returns the distance that the marker is from the camera . If no marker is visible, returns None.

Parameters:

None

Returns:

float

The distance that the ARTag marker is from the camera in meters.

Examples

>>> from rover_api.discover_tracking import Tracker
>>> tracker = Tracker()
>>> if tracker.get_marker_visible():
>>>     print(tracker.get_marker_distance())

get_marker_id() → int

A function that returns the ID of the ARTag marker. If no marker is visible, returns None

Parameters:

None

Returns:

int

The ID of the ARTag marker as a value between 0 and 17.

Examples

>>> from rover_api.discover_tracking import Tracker
>>> tracker = Tracker()
>>> if tracker.get_marker_visible():
>>>     print(tracker.get_marker_id())

get_marker_visible() → bool

A function that returns the value of the marker_visible flag.

Parameters:

None

Returns:

bool

This boolean represents whether or not the rover’s camera has detected an ARTag marker.

Examples

>>> from rover_api.discover_tracking import Tracker
>>> tracker = Tracker()
>>> is_visible = tracker.get_marker_visible()

subscribe_to_marker_topic()

Subscribes to ROS /visualization_marker topic published by the alavar tracking node. If subscribe is set to False, call this function to get data from the tracking node

Parameters:

None

Returns:

None

Examples

>>> from rover_api.discover_tracking import Tracker
>>> tracker = Tracker(False)
>>> tracker.subscribe_to_marker_topic()