# initializeTrack

Initialize new track in tracker

## Syntax

``trackID = initializeTrack(tracker,track)``
``trackID = initializeTrack(tracker,track,filter)``

## Description

example

````trackID = initializeTrack(tracker,track)` initializes a new track in the `tracker`. The tracker must be updated at least once before initializing a track. If the track is initialized successfully, the tracker assigns the output `trackID` to the track, sets the `UpdateTime` of the track equal to the last step time in the tracker, and synchronizes the data in the input `track` to the initialized track. A warning is issued if the tracker already maintains the maximum number of tracks specified by its`MaxNumTracks` property. In this case, the `trackID` is returned as `0`, which indicates a failure to initialize the track.```
````trackID = initializeTrack(tracker,track,filter)` initializes a new track in the `tracker`, using a specified tracking filter, `filter`. ```

## Examples

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Create a radar tracker and update the tracker with detections at $\mathit{t}=0$ and $\mathit{t}=1$second.

`tracker = radarTracker`
```tracker = radarTracker with properties: TrackerIndex: 0 FilterInitializationFcn: 'initcvekf' AssignmentThreshold: [30 Inf] MaxNumTracks: 100 MaxNumDetections: Inf MaxNumSensors: 20 OOSMHandling: 'Terminate' ConfirmationThreshold: [2 3] DeletionThreshold: [5 5] HasCostMatrixInput: false HasDetectableTrackIDsInput: false StateParameters: [1x1 struct] NumTracks: 0 NumConfirmedTracks: 0 ```
```detection1 = objectDetection(0,[1;1;1]); detection2 = objectDetection(1,[1.1;1.2;1.1]); tracker(detection1,0); currentTrack = tracker(detection2,1);```

As seen from the `NumTracks` property, the tracker now maintains one track.

`tracker`
```tracker = radarTracker with properties: TrackerIndex: 0 FilterInitializationFcn: 'initcvekf' AssignmentThreshold: [30 Inf] MaxNumTracks: 100 MaxNumDetections: Inf MaxNumSensors: 20 OOSMHandling: 'Terminate' ConfirmationThreshold: [2 3] DeletionThreshold: [5 5] HasCostMatrixInput: false HasDetectableTrackIDsInput: false StateParameters: [1x1 struct] NumTracks: 1 NumConfirmedTracks: 1 ```

Create a new track using the `objectTrack` object.

`newTrack = objectTrack()`
```newTrack = objectTrack with properties: TrackID: 1 BranchID: 0 SourceIndex: 1 UpdateTime: 0 Age: 1 State: [6x1 double] StateCovariance: [6x6 double] StateParameters: [1x1 struct] ObjectClassID: 0 ObjectClassProbabilities: 1 TrackLogic: 'History' TrackLogicState: 1 IsConfirmed: 1 IsCoasted: 0 IsSelfReported: 1 ObjectAttributes: [1x1 struct] ```

Initialize a track in the GNN tracker object using the newly created track.

`trackID = initializeTrack(tracker,newTrack)`
```trackID = uint32 2 ```

As seen from the `NumTracks` property, the tracker now maintains two tracks.

`tracker`
```tracker = radarTracker with properties: TrackerIndex: 0 FilterInitializationFcn: 'initcvekf' AssignmentThreshold: [30 Inf] MaxNumTracks: 100 MaxNumDetections: Inf MaxNumSensors: 20 OOSMHandling: 'Terminate' ConfirmationThreshold: [2 3] DeletionThreshold: [5 5] HasCostMatrixInput: false HasDetectableTrackIDsInput: false StateParameters: [1x1 struct] NumTracks: 2 NumConfirmedTracks: 2 ```

## Input Arguments

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Radar tracker, specified as a `radarTracker` object.

New track to be initialized, specified as an `objectTrack` object or a structure. If specified as a structure, the name, variable type, and data size of the fields of the structure must be the same as the name, variable type, and data size of the corresponding properties of the `objectTrack` object.

Data Types: `struct` | `object`

## Output Arguments

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Track identifier, returned as a nonnegative integer. `trackID` is returned as 0 if the `track` is not initialized successfully.

Example: `2`

## Version History

Introduced in R2021a