Basic usage


For a complete sample of real-time recognition of a video stream from the device's camera, see example app.

Before proceeding with this procedure, you must have followed the steps described in Adding SDK and authenticating.

The basic use of Live Sense SDK includes the detection of cars, pedestrians,signs, or other supported objects in a live camera feed.

For details on what can be detected by each model, see Models.

In your view controller, use the following code to run Roadbasics, the default model for detection.

  @IBOutlet weak var previewView: UIView!
  var videoCapture: LSDVideoCapture = LSDVideoCapture()
  var lsdRecognition : LSDPixelBufferRecognition?

  override func viewDidLoad() {
      videoCapture.delegate = self
      lsdRecognition = LSDPixelBufferRecognition()
      lsdRecognition?.delegate = self

      var modelOptions : ModelOptions = ModelOptions()
      let rbModelOptions : RoadBasicsModelOptions = RoadBasicsModelOptions()
      let rbModel = RoadBasicsModel(options: modelOptions, rbModelOptions: rbModelOptions)

      videoCapture.setUp(sessionPreset: .hd1280x720) { [unowned self] success in
          if success {

              // Add the video preview into the UI.
              if let previewLayer = self.videoCapture.previewLayer {


              // Once everything is set up, we can start capturing live video.
              self.lsdRecognition?.initiateDetectionRequest(isParallel: true, forModels:[rbModel]) { (success) in


For passing other models, you can pass the model key for that model. You can get the model keys for the following code, or refer to Models for more details:

  public func getModelData() -> Array<ModelConfiguration>

To get the stats for detections, implement the LSDVideoCaptureStatisticsDelegate methods.

@objc public protocol LSDVideoCaptureStatisticsDelegate: class {
  @objc optional func getVideoStats(inferenceTime: Int, executionTime: Int, fps: Int, droppedFrames : Int)
    @objc optional func output(sampleBuffer: CMSampleBuffer,videoOutput:AVCaptureVideoDataOutput)
    @objc optional func displayFrameCounter(_ frame: Int)
    @objc optional func sendObservationInformation(_ aObservationInfo: String, aConfidence: Float)
    @objc optional func sendObservation(infoDictionary aDict: NSDictionary)
    @objc optional func alertReceived(alerts : [LSDAlert])


Use the following recognition session lifecycle methods in your view controller's lifecycle methods - Method 1 and Method 2.

Method 1
Method 2
override func viewDidAppear(_ animated: Bool) {
  NotificationCenter.default.addObserver(self, selector: #selector(willResignActive), name: UIApplication.willResignActiveNotification, object: nil)
  NotificationCenter.default.addObserver(self, selector: #selector(willBecomeActive), name: UIApplication.willEnterForegroundNotification, object: nil)
@objc func willResignActive() {
@objc func willBecomeActive() {

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