ios - swift 4 : How to create a face map with ios11 vision framework from face landmark points

Question

我正在使用 iOS 11 视觉框架实时生成面部标志点。我能够获取面部标志点并使用面部标志点的 UIBezierPath 覆盖相机层。但是，我想得到类似右下角图片的东西。目前我有一些看起来像左图的东西，我尝试循环遍历这些点并添加中点，但我不知道如何从这些点生成所有这些三角形。我将如何根据左侧的点生成右侧的 map ？

我不确定我是否可以使用所有的点，并不是说它会有太大帮助，但我也有来自整个面部边界框的点。最后，有没有什么框架可以让我识别所有我需要的点，比如openCV或者其他的，请告诉我。谢谢!

这是我一直在使用的代码 https://github.com/DroidsOnRoids/VisionFaceDetection :

func detectLandmarks(on image: CIImage) {
    try? faceLandmarksDetectionRequest.perform([faceLandmarks], on: image)
    if let landmarksResults = faceLandmarks.results as? [VNFaceObservation] {

        for observation in landmarksResults {

            DispatchQueue.main.async {
                if let boundingBox = self.faceLandmarks.inputFaceObservations?.first?.boundingBox {
                    let faceBoundingBox = boundingBox.scaled(to: self.view.bounds.size)
                    //different types of landmarks



                    let faceContour = observation.landmarks?.faceContour
                    self.convertPointsForFace(faceContour, faceBoundingBox)

                    let leftEye = observation.landmarks?.leftEye
                    self.convertPointsForFace(leftEye, faceBoundingBox)

                    let rightEye = observation.landmarks?.rightEye
                    self.convertPointsForFace(rightEye, faceBoundingBox)

                    let leftPupil = observation.landmarks?.leftPupil
                    self.convertPointsForFace(leftPupil, faceBoundingBox)

                    let rightPupil = observation.landmarks?.rightPupil
                    self.convertPointsForFace(rightPupil, faceBoundingBox)

                    let nose = observation.landmarks?.nose
                    self.convertPointsForFace(nose, faceBoundingBox)

                    let lips = observation.landmarks?.innerLips
                    self.convertPointsForFace(lips, faceBoundingBox)

                    let leftEyebrow = observation.landmarks?.leftEyebrow
                    self.convertPointsForFace(leftEyebrow, faceBoundingBox)

                    let rightEyebrow = observation.landmarks?.rightEyebrow
                    self.convertPointsForFace(rightEyebrow, faceBoundingBox)

                    let noseCrest = observation.landmarks?.noseCrest
                    self.convertPointsForFace(noseCrest, faceBoundingBox)

                    let outerLips = observation.landmarks?.outerLips
                    self.convertPointsForFace(outerLips, faceBoundingBox)
                }
            }
        }
    }

}

func convertPointsForFace(_ landmark: VNFaceLandmarkRegion2D?, _ boundingBox: CGRect) {
    if let points = landmark?.points, let count = landmark?.pointCount {
        let convertedPoints = convert(points, with: count)



        let faceLandmarkPoints = convertedPoints.map { (point: (x: CGFloat, y: CGFloat)) -> (x: CGFloat, y: CGFloat) in
            let pointX = point.x * boundingBox.width + boundingBox.origin.x
            let pointY = point.y * boundingBox.height + boundingBox.origin.y

            return (x: pointX, y: pointY)
        }

        DispatchQueue.main.async {
            self.draw(points: faceLandmarkPoints)
        }
    }
}


func draw(points: [(x: CGFloat, y: CGFloat)]) {
    let newLayer = CAShapeLayer()
    newLayer.strokeColor = UIColor.blue.cgColor
    newLayer.lineWidth = 4.0

    let path = UIBezierPath()
    path.move(to: CGPoint(x: points[0].x, y: points[0].y))
    for i in 0..<points.count - 1 {
        let point = CGPoint(x: points[i].x, y: points[i].y)
        path.addLine(to: point)
        path.move(to: point)
    }
    path.addLine(to: CGPoint(x: points[0].x, y: points[0].y))
    newLayer.path = path.cgPath

    shapeLayer.addSublayer(newLayer)
}

Answer 1

我最终找到了一个可行的解决方案。我通过 https://github.com/AlexLittlejohn/DelaunaySwift 使用了 delaunay 三角测量，我修改了它以处理通过视觉框架的人脸标志检测请求生成的点。这不容易用代码片段来解释，所以我在下面链接了我的 github 存储库，它显示了我的解决方案。请注意，这不会从前额获取点，因为视觉框架只会从眉毛以下获取点。

https://github.com/ahashim1/Face