"""Contains collection of error based deleters"""
from typing import Sequence
import numpy as np
from ..base import Property
from .base import Deleter
[docs]
class CovarianceBasedDeleter(Deleter):
""" Track deleter based on covariance matrix size.
Deletes tracks whose state covariance matrix (more specifically its trace)
exceeds a given threshold.
"""
covar_trace_thresh: float = Property(doc="Covariance matrix trace threshold")
mapping: Sequence[int] = Property(default=None,
doc="Track state vector indices whose corresponding "
"covariances' sum is to be considered. Defaults to"
"None, whereby the entire track covariance trace is "
"considered.")
[docs]
def check_for_deletion(self, track, **kwargs):
"""Check if a given track should be deleted
A track is flagged for deletion if the trace of its state covariance
matrix is higher than :py:attr:`~covar_trace_thresh`.
Parameters
----------
track : Track
A track object to be checked for deletion.
Returns
-------
bool
`True` if track should be deleted, `False` otherwise.
"""
diagonals = np.diag(track.state.covar)
if self.mapping:
track_covar_trace = np.sum(diagonals[self.mapping])
else:
track_covar_trace = np.sum(diagonals)
if track_covar_trace > self.covar_trace_thresh:
return True
return False