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Object Tracker

Related documentations
Map Manager
Tracker Coordinate System
Visual SLAM Learning Guide

The Object Tracker loads the map file and renders 3D object on it.

Please refer Visual SLAM Learning Guide to create a map more precisely while scanning 3D space.

Create Instants
Start / Stop Tracker
Use Tracking Information
Set Map
Add / Replace Map
Change Tracking Mode

Create Instants

>ObjectTrackerViewController.swift

var cameraDevice:MasCameraDevice = MasCameraDevice()
var sensorDevice:MasSensorDevice = MasSensorDevice()
var trackingManager:MasTrackerManager = MasTrackerManager()

Start / Stop Tracker

To start / stop Tracker after loading the map, refer to the following code.

>ObjectTrackerViewController.swift

@objc func resumeAR()
{
    ...
    trackingManager.start(.TRACKER_TYPE_OBJECT)
}

@objc func pauseAR()
{
    trackingManager.stopTracker()
    ...
}

Use Tracking Information

To use the Tracking information, refer to the following code.

>ObjectTrackerViewController.swift

override func glkView(_ view: GLKView, drawIn rect: CGRect) {
        
    ...
    
    let trackingState:MasTrackingState = trackingManager.updateTrackingState()
    let result:MasTrackingResult = trackingState.getTrackingResult()
    
        let backgroundImage:MasTrackedImage = trackingState.getImage()
        let backgroundProjectionMatrix:matrix_float4x4 = cameraDevice.getBackgroundPlaneProjectionMatrix()
        
        if let cameraQuad = backgroundCameraQuad {
            cameraQuad.draw(image:backgroundImage, projectionMatrix: backgroundProjectionMatrix)
        }
    
    glEnable(GLenum(GL_DEPTH_TEST))
    
    let projectionMatrix:matrix_float4x4 = cameraDevice.getProjectionMatrix()
    
    let trackingCount:Int32 = result.getCount()
    
    for i in stride(from: 0, to: trackingCount, by: 1) {
        let trackable:MasTrackable = result.getTrackable(i)
        textureCube.setProjectionMatrix(projectionMatrix: projectionMatrix)
        textureCube.setPoseMatrix(poseMatrix: trackable.getPose())
        textureCube.setTranslation(x: 0.0, y: 0.0, z: -0.05)
        textureCube.setScale(x: 0.3, y: 0.3, z: 0.01)
        textureCube.draw()
    }
    
    glDisable(GLenum(GL_DEPTH_TEST))
}

Set Map

By calling function addTrackerData to register the map file and calling function loadTrackerData, Space can be tracked. To set a map, refer to the following code.

>ObjectTrackerViewController.swift

func startEngin()
{
    ...
    trackingManager.addTrackerData(objectTrackerMapPath)
    trackingManager.loadTrackerData()
}

Add / Replace Map

  1. Create a map file refer to Map Manager.

  2. Copy the received map file to the desired path.

  3. Set a map.

  4. If you have an existing map file, call function 'addTrackerData' and function 'loadTrackerData' after calling trackingManager.removeTrackerData()

Change Tracking Mode

2 Tracking Modes of Object Tracker:

JITTER_REDUCTION_ACTIVATION, JITTER_REDUCTION_DEACTIVATION

  • JITTER_REDUCTION_ACTIVATION: Default Setting. Jitter reduction.
trackingManager.setTrackingOption(.JITTER_REDUCTION_ACTIVATION)
  • JITTER_REDUCTION_DEACTIVATION: Disable the jitter reduction option.
trackingManager.setTrackingOption(.JITTER_REDUCTION_DEACTIVATION)