Big thanks go to Christian Würthner for the library CameraX-Object-Tracking

About

A small library allowing you to analyze images and track objects on interpolated paths.

See this Medium article for more details: https://medium.com/@cwurthner/object-detection-and-tracking-with-firebase-ml-kit-and-camerax-ml-product-search-part-3-8bd138257101
See this sample app: https://github.com/crysxd/Object-Tracking-Demo/
See this youtube video of the sample app: https://youtu.be/ME9iE0CYHeY

How to use

Add this in module's build.gradle

allprojects {
    repositories {
        maven { url 'https://jitpack.io' }
    }
}

Add this is app's build.gralde

implementation 'com.github.crysxd:CameraX-Object-Tracking:latest-version'

Add a instance of cz.rusakov.cameraXCompleteTracker.CameraFragment to your layout:

<fragment
        android:id="@+id/cameraFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:name="cz.rusakov.cameraXCompleteTracker.CameraFragment"/>

CameraFragment will handle the entire camera for you and display a preview image. In your Activity or Fragment use this code to set eveything up:

private lateinit var imageAnalyzer: MyImageAnalyzer

private val camera
    get() = supportFragmentManager.findFragmentById(R.id.cameraFragment) as CameraFragment

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)

    val boundingBoxArOverlay = BoundingBoxArOverlay(this, BuildConfig.DEBUG)
    imageAnalyzer = ViewModelProviders.of(this).get(MyImageAnalyzer::class.java)

    camera.imageAnalyzer = imageAnalyzer
    camera.arOverlayView.observe(camera, Observer {
        it.doOnLayout { view ->
            imageAnalyzer.arObjectTracker
                .pipe(PositionTranslator(view.width, view.height))
                .pipe(PathInterpolator())
                .addTrackingListener(boundingBoxArOverlay)
        }

        it.add(boundingBoxArOverlay)
    })
}

And implement ThreadedImageAnalyzer like this:

class MyImageAnalyzer : ViewModel(), ThreadedImageAnalyzer {

    val arObjectTracker = ArObjectTracker()
    private val uiHandler = Handler(Looper.getMainLooper())
    private val handlerThread = HandlerThread("MyImageAnalyzer").apply { start() }

    override fun getHandler() = Handler(handlerThread.looper)

    override fun analyze(image: ImageProxy, rotationDegrees: Int) {
        val imageSize = Size(image.width, image.height)

        // Fancy computation with image here

        uiHandler.post {
            arObjectTracker.processObject(
                if (fancyComputationWasSuccessfull) {
                    ArObject(
                        trackingId = o.trackingId ?: -1 /* An ID of the tracked object, e.g. from Firebase ML Kit*/,
                        boundingBox = o.boundingBox.toRectF() /* The bounding box */,
                        sourceSize = imageSize /* See above, the size of the input image */,
                        sourceRotationDegrees = rotationDegrees /* See above, the roation of the input image */
                    )
                } else {
                    null
                }
            )
        }
     }   
  }

Use front facing camera

Use FrontFacingCameraFragment instead:

<fragment
        android:id="@+id/cameraFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:name="cz.rusakov.cameraXCompleteTracker.CameraFragment"/>

Tell PositionTranslator that we use the front facing camera:

.pipe(PositionTranslator(view.width, view.height))

Custom image sizes and option

You can subclass CameraFragment and override onCreateAnalyzerConfigBuilder and/or onCreatePreivewConfigBuilder