Swift 视觉框架，用于检测向上/向下看的人脸

我正在使用视觉框架来检测人脸方向。VNFaceObservation具有横摇和偏航特性，但不幸的是没有俯仰。如何计算音高值？我需要检查一个人是向上看还是向下看

另一个论坛中有人建议我使用瞳孔和眉毛之间的距离，但我并没有得到好的结果，尤其是当人们改变与屏幕的距离时，因为这种差异不同。我试图用face boundingBox height来划分差异，但该值也是动态的，当用户抬起头时，面周围的框变小了

面容迥异的人则是另一回事。有人用Vision实现过这样的功能吗？ 谢谢你的帮助

   var origins: [CGPoint] = []
  //  origin based on left and right pupil
  if let point = result.landmarks?.leftPupil?.normalizedPoints.first {
    let origin = landmark(point: point, to: result.boundingBox)
    origins.append(origin)
  }
  if let point = result.landmarks?.rightPupil?.normalizedPoints.first {
    let origin = landmark(point: point, to: result.boundingBox)
    origins.append(origin)
  }
 
  // Calculate the average y coordinate of the origins.
  let avgY = origins.map { $0.y }.reduce(0.0, +) / CGFloat(origins.count)
  
  // get eyebrow locations
  var eyebrowOrigins: [CGPoint] = []
    var heights: [CGPoint] = []
    
    
  if let point = result.landmarks?.leftEyebrow?.normalizedPoints.first {
    let origin = landmark(point: point, to: result.boundingBox)
    eyebrowOrigins.append(origin)
  }
  if let point = result.landmarks?.rightEyebrow?.normalizedPoints.first {
    let origin = landmark(point: point, to: result.boundingBox)
    eyebrowOrigins.append(origin)
  }
  
  // Calculate the average y coordinate of the eye brows.
  let eyebrowAvgY = eyebrowOrigins.map { $0.y }.reduce(0.0, +) / CGFloat(origins.count)
  
  // compare pupils location to eye brows
  
  var focusY: CGFloat = 0
    let diff = avgY - eyebrowAvgY

  // approximate face height inside the bounding box
    let faceHeight = result.boundingBox.height