Single object track report
objectTrack captures the track information of a single object.
objectTrack is the standard output format for trackers.
track = objectTrackobjectTrack object with default property values. An
objectTrack object contains information like the age and state of a
single track.
track = objectTrack(Name,Value)
TrackID — Unique track identifier1 (default) | nonnegative integerUnique track identifier, specified as a nonnegative integer. This property distinguishes different tracks.
Example:
2
BranchID — Unique track branch identifier0 (default) | nonnegative integerUnique track branch identifier, specified as a nonnegative integer. This property distinguishes different track branches.
Example:
1
SourceIndex — Index of source track reporting system1 (default) | nonnegative integerIndex of source track reporting system, specified as a nonnegative integer. This property identifies the source that reports the track.
Example:
3
ObjectClassID — Object class identifier0 (default) | nonnegative integerObject class identifier, specified as a nonnegative integer. This property distinguishes between different user-defined types of objects. For example, you can use 1 for objects of type "car", and 2 for objects of type "pedestrian". 0 is reserved for unknown classification.
Example:
3
UpdateTime — Update time of track0 (default) | nonnegative real scalarTime at which the track was updated by a tracker, specified as a nonnegative real scalar.
Example: 1.2
Data Types: single | double
Age — Number of times track was updated1 (default) | positive integerNumber of times the track was updated, specified as a positive integer. When a track
is initialized, its Age is equal to 1. Any
subsequent update with a hit or miss increases the track Age by 1.
Example:
2
State — Current state of trackzeros(6,1) (default) | real-valued N-element vectorThe current state of the track at the UpdateTime, specified as
a real-valued N-element vector, where N is the
dimension of the state. The format of track state depends on the model used to track the
object. For example, for 3-D constant velocity model used with constvel, the state vector is [x;
vx; y;
vy; z;
vz].
Example:
[1 0.2 3 0.2]
Data Types: single | double
StateCovariance — Current state uncertainty covariance of trackeye(6,6) (default) | real positive semidefinite symmetric N-by-N
matrixThe current state uncertainty covariance of the track, specified as a real positive
semidefinite symmetric N-by-N matrix, where
N is the dimension of state specified in the
State property.
Data Types: single | double
TrackLogic — Track confirmation and deletion logic type'History' (default) | 'Integrated' | 'Score'Confirmation and deletion logic type, specified as:
'History' – Track confirmation and deletion is based on the
number of times the track has been assigned to a detection in the latest tracker
updates.
'Score' – Track confirmation and deletion is based on a
log-likelihood track score. A high score means that the track is more likely to be
valid. A low score means that the track is more likely to be a false alarm.
'Integrated' – Track confirmation and deletion is based on
the integrated probability of track existence.
TrackLogicState — State of track logicThe current state of the track logic type. Based on the logic type specified in the
TrackLogic property, the logic state is specified as:
'History' – A 1-by-M logical vector,
where M is the number of latest track logical states recorded.
true (1) values indicate hits, and false
(0) values indicate misses. For example, [1 0 1 1 1] represents
four hits and one miss in the last five updates. The default value for logic state
is 1.
'Score' – A 1-by-2 real-valued vector,
[cs, ms]. cs is the
current score, and ms is the maximum score. The default value
is [0, 0].
'Integrated' – A nonnegative scalar. The scalar represents
the integrated probability of existence of the track. The default value is
0.5.
IsConfirmed — Indicate if track is confirmedtrue (default) | falseIndicate if the track is confirmed, specified as true or
false.
Data Types: logical
IsCoasted — Indicate if track is coastedfalse (default) | trueIndicate if the track is coasted, specified as true or
false. A track is coasted if its latest update is based on
prediction instead of correction using detections.
Data Types: logical
IsSelfReported — Indicate if track is self reportedtrue (default) | falseIndicate if the track is self reported, specified as true or
false. A track is self reported if it is reported from internal
sources (senors, trackers, or fusers). To limit the propagation of rumors in a tracking
system, use the value false if the track was updated by an external
source.
Example: false
Data Types: logical
ObjectAttributes — Object attributesstruct() (default) | structureObject attributes passed by the tracker, specified as a structure.
StateParameters — Parameters of the track state reference framestruct() (default) | structure | structure arrayParameters of the track state reference frame, specified as a structure or a structure array. Use this property to define the track state reference frame and how to transform the track from the source coordinate system to the fuser coordinate system.
toStruct | Convert objectTrack object to
struct |
objectTrackCreate a report of a track using objectTrack.
x = (1:6)'; P = diag(1:6); track = objectTrack('State',x,'StateCovariance',P); disp(track)
objectTrack with properties:
TrackID: 1
BranchID: 0
SourceIndex: 1
UpdateTime: 0
Age: 1
State: [6x1 double]
StateCovariance: [6x6 double]
StateParameters: [1x1 struct]
ObjectClassID: 0
TrackLogic: 'History'
TrackLogicState: 1
IsConfirmed: 1
IsCoasted: 0
IsSelfReported: 1
ObjectAttributes: [1x1 struct]
The TrackLogic property can only be set during
construction.
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