MainActivity.kt

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        val objectPredictor = FritzVisionObjectPredictor.getInstance(this)
        var fritzVisionImage: FritzVisionImage
        cameraView.addFrameProcessor { frame ->
            if (yuvDataLength == 0) {
                //Run this only once
                initializeData()
            }
            //Camera Preview returns NV21, so convert it to Bitmap :
            //https://stackoverflow.com/a/43551798/5471095
            allocationIn.copyFrom(frame.data) //Take the NV21 format
            yuvToRGB.forEach(allocationOut)  //Convert it to Bitmap readable format
            allocationOut.copyTo(bitmapOut)   //Set it to the empty Bitmap created earlier
            //Create a fritzVisionImage
            fritzVisionImage = FritzVisionImage.fromBitmap(bitmapOut)
        }
    }
}