Question

你好我们正在尝试整合Vision框架来检测一张脸并跟踪双眼，然后我试图测量Vision检测到的脸部中心之间的距离。我现在的问题是如何根据Vision给我的眼睛中心的两个点来获得现实世界中的这个距离。识别到脸部后，我使用以下代码计算眼睛中心之间的距离

guard let sceneView = self.view as? ARSKView, let currentFrame = sceneView.session.currentFrame else {
                return
            }
            let w = face.boundingBox.size.width * image.size.width
            let h = face.boundingBox.size.height * image.size.height
            let x = face.boundingBox.origin.x * image.size.width
            let y = face.boundingBox.origin.y * image.size.height
            // left pupil
                context?.saveGState()
                context?.setStrokeColor(UIColor.yellow.cgColor)
                var leftIrisLocation = CGPoint()
                if let landmark = face.landmarks?.leftPupil {
                    for i in 0...landmark.pointCount - 1 { // last point is 0,0
                        let point = landmark.normalizedPoints[i]
                        if i == 0 {
                            leftIrisLocation = CGPoint(x: x + CGFloat(point.x) * w, y: y + CGFloat(point.y) * h)
                            context?.move(to: leftIrisLocation)
                            context?.addEllipse(in: CGRect(origin: leftIrisLocation, size: CGSize(width: 10, height: 10)))
                        }
                    }
                }
                context?.closePath()
                context?.setLineWidth(8.0)
                context?.drawPath(using: .stroke)
                context?.saveGState()

                // right pupil
                context?.saveGState()
                context?.setStrokeColor(UIColor.yellow.cgColor)
                var rightIrisLocation = CGPoint()
                if let landmark = face.landmarks?.rightPupil {
                    for i in 0...landmark.pointCount - 1 { // last point is 0,0
                        let point = landmark.normalizedPoints[i]
                        if i == 0 {
                            rightIrisLocation = CGPoint(x: x + CGFloat(point.x) * w, y: y + CGFloat(point.y) * h)
                            context?.move(to: rightIrisLocation)
                            context?.addEllipse(in: CGRect(origin: rightIrisLocation, size: CGSize(width: 10, height: 10)))
                        }
                    }
                }
                let distanceFromIris = self.distanceFrom(p1: leftIrisLocation, to: rightIrisLocation)

此时我在图像上有距离但没有真实世界距离，所以我尝试在当前帧上点击测试以获得从每只眼睛到相机的距离，然后使用毕达哥拉斯定理计算最终距离如下：

       for leftResult in currentFrame.hitTest(leftIrisLocation, types: [.featurePoint, .existingPlaneUsingExtent]) {
            print("Distance left iris to camera")
            print(leftResult.distance)
        }

        for rightResult in currentFrame.hitTest(rightIrisLocation, types: [.featurePoint, .existingPlaneUsingExtent]) {
            print("Distance right iris to camera")
            print(rightResult.distance)
        }

        let distanceBetweenIris = sqrt((leftResult.distance * leftResult.distance) - (rightResult.distance * rightResult.distance))

但是这个distanceBetweenIris变得非常大，像20厘米，应该接近5厘米~6厘米，任何想法如何减少这个大错误？

眼睛之间的ARKit距离

0 个答案: