Swift Arkit-如何跟踪移动宠物

Question

我需要编写一个可以识别猫或狗的应用程序，并测量每分钟的呼吸数量。 为此，我想每100毫秒从CAT区域拿出100个颜色的点。这些点将通过傅立叶变换功能来处理，该功能根据周期性的变化来测量猫的呼吸。

视觉库可以通过相机快照来检测猫或狗，但恐怕每100ms aranchor将放置在其他地方，我将无法从猫那里获得相同的100点区域。

这是我的ViewController：

import SceneKit
import ARKit
import Vision

class ViewController: UIViewController, ARSCNViewDelegate, ARSessionDelegate {
    
    var detectionAvailableUntil: Int64 = .zero
    @IBOutlet var sceneView: ARSCNView!
    private var viewportSize: CGSize!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        sceneView.delegate = self
        viewportSize = sceneView.frame.size
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        resetTracking()
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        sceneView.session.pause()
    }
    
    private func resetTracking() {
        let configuration = ARWorldTrackingConfiguration()
        configuration.planeDetection = []
        sceneView.session.run(configuration)
    }
    
    lazy var catRequest: VNRecognizeAnimalsRequest = {
        do {
            let req = VNRecognizeAnimalsRequest() { [weak self] request, error in
                self?.processCatDetections(for: request as! VNRecognizeAnimalsRequest, error: error)
            }
            
            return req
        } catch {
            fatalError("Fatal error")
        }
    }()
    
    func processCatDetections(for request: VNRecognizeAnimalsRequest, error: Error?) {
        guard error == nil else {
            print("Object detection error: \(error!.localizedDescription)")
            return
        }
        if let result = request.results?.first as? VNRecognizedObjectObservation {
            let cats = result.labels.filter({$0.identifier == "Cat"})
            for _ in cats {
                guard let currentFrame = self.sceneView.session.currentFrame,
                      result.confidence > 0.3 else { continue }
                let fromCameraImageToViewTransform = currentFrame.displayTransform(for: .portrait, viewportSize: self.viewportSize)
                let boundingBox = result.boundingBox
                let viewNormalizedBoundingBox = boundingBox.applying(fromCameraImageToViewTransform)
                let t = CGAffineTransform(scaleX: self.viewportSize.width, y: self.viewportSize.height)
                let viewBoundingBox = viewNormalizedBoundingBox.applying(t)
                let midPoint = CGPoint(x: viewBoundingBox.midX, y: viewBoundingBox.midY)
                let results = self.sceneView.hitTest(midPoint, types: .featurePoint)
                guard let result = results.first else { continue }
                let anchor = ARAnchor(name: "catAnchor", transform: result.worldTransform)
                self.sceneView.session.add(anchor: anchor)
            }
        }
    }
    
    func renderer(_ renderer: SCNSceneRenderer, willRenderScene scene: SCNScene, atTime time: TimeInterval) {
        guard let capturedImage = sceneView.session.currentFrame?.capturedImage else { return }
        let requestHandler = VNImageRequestHandler(cvPixelBuffer: capturedImage)
        
        do {
            try requestHandler.perform([self.catRequest])
        } catch {
            print("Error: Vision request failed")
        }
    }
    
    func renderer(_ renderer: SCNSceneRenderer, didAdd node: SCNNode, for anchor: ARAnchor) {
        let date = Int64(NSDate().timeIntervalSince1970 * 1000)
        guard anchor.name == "catAnchor",
              date > self.detectionAvailableUntil else { return }
        print("catAnchor added")
        self.detectionAvailableUntil = Int64(NSDate().timeIntervalSince1970 * 1000 + 500)
        let sphereNode = SCNNode(geometry: SCNSphere(radius: 0.01))
        sphereNode.geometry?.firstMaterial?.diffuse.contents = UIColor.red
        sphereNode.simdWorldTransform = anchor.transform
        node.addChildNode(sphereNode)
    }
}

问题是Spherenode是在猫区（腹部或头部）的不同位置绘制的。

Apple提供了跟踪人体或面部的库，因此我想我需要arfaceanchor或Arbodyandanchor，但对于Cat。

如果该应用程序能够跟踪CAT，则它将能够在Aranchor中检索相同的点。

是否可以？