Is there any where are you to get distance between camera and face using ARKit ?
I think this is possible by using the ARFaceAnchor.leftEyeTransform
and ARFaceAnchor.rightEyeTransform
properties.
Once you have these you can get the approximate distance of the eyes to the Camera using the worldPosition
of the Eyes and subtracting the position of the Camera e.g. SCNVector3Zero
.
Below is a very crude example with all the code commented so it should be easy enough to understand:
//------------------------------
// MARK: - SCNVector3 Extensions
//------------------------------
extension SCNVector3{
///Get The Length Of Our Vector
func length() -> Float { return sqrtf(x * x + y * y + z * z) }
///Allow Us To Subtract Two SCNVector3's
static func - (l: SCNVector3, r: SCNVector3) -> SCNVector3 { return SCNVector3Make(l.x - r.x, l.y - r.y, l.z - r.z) }
}
//--------------------------
// MARK: - ARSCNViewDelegate
//--------------------------
extension ViewController: ARSCNViewDelegate{
func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
//1. Setup The FaceNode & Add The Eyes
faceNode = node
faceNode.addChildNode(leftEye)
faceNode.addChildNode(rightEye)
faceNode.transform = node.transform
//2. Get The Distance Of The Eyes From The Camera
trackDistance()
}
func renderer(_ renderer: SCNSceneRenderer, didUpdate node: SCNNode, for anchor: ARAnchor) {
faceNode.transform = node.transform
//2. Check We Have A Valid ARFaceAnchor
guard let faceAnchor = anchor as? ARFaceAnchor else { return }
//3. Update The Transform Of The Left & Right Eyes From The Anchor Transform
leftEye.simdTransform = faceAnchor.leftEyeTransform
rightEye.simdTransform = faceAnchor.rightEyeTransform
//4. Get The Distance Of The Eyes From The Camera
trackDistance()
}
/// Tracks The Distance Of The Eyes From The Camera
func trackDistance(){
DispatchQueue.main.async {
//4. Get The Distance Of The Eyes From The Camera
let leftEyeDistanceFromCamera = self.leftEye.worldPosition - SCNVector3Zero
let rightEyeDistanceFromCamera = self.rightEye.worldPosition - SCNVector3Zero
//5. Calculate The Average Distance Of The Eyes To The Camera
let averageDistance = (leftEyeDistanceFromCamera.length() + rightEyeDistanceFromCamera.length()) / 2
let averageDistanceCM = (Int(round(averageDistance * 100)))
print("Approximate Distance Of Face From Camera = \(averageDistanceCM)")
}
}
}
class ViewController: UIViewController{
@IBOutlet var sceneView: ARSCNView!
var faceNode = SCNNode()
var leftEye = SCNNode()
var rightEye = SCNNode()
//-----------------------
// MARK: - View LifeCycle
//-----------------------
override func viewDidLoad() {
super.viewDidLoad()
//1. Set Up Face Tracking
guard ARFaceTrackingConfiguration.isSupported else { return }
let configuration = ARFaceTrackingConfiguration()
configuration.isLightEstimationEnabled = true
sceneView.delegate = self
sceneView.showsStatistics = true
sceneView.session.run(configuration, options: [.resetTracking, .removeExistingAnchors])
//2. Setup The Eye Nodes
setupEyeNode()
}
override func viewWillAppear(_ animated: Bool) { super.viewWillAppear(animated) }
//-----------------------
// MARK: - Eye Node Setup
//-----------------------
/// Creates To SCNSpheres To Loosely Represent The Eyes
func setupEyeNode(){
//1. Create A Node To Represent The Eye
let eyeGeometry = SCNSphere(radius: 0.005)
eyeGeometry.materials.first?.diffuse.contents = UIColor.cyan
eyeGeometry.materials.first?.transparency = 1
//2. Create A Holder Node & Rotate It So The Gemoetry Points Towards The Device
let node = SCNNode()
node.geometry = eyeGeometry
node.eulerAngles.x = -.pi / 2
node.position.z = 0.1
//3. Create The Left & Right Eyes
leftEye = node.clone()
rightEye = node.clone()
}
}
Hope it helps...
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