Question

我正在尝试在用户的脸上放置一个方形矩形，我通过全屏（CIFaceFeature）视频源实时识别self.view.frame。但是，我从CIFaceFeature.bounds获得的坐标来自与视图使用的坐标系不同的坐标系。我尝试过从this和other examples转换这些坐标。但是，由于我没有在视频输入上运行此功能，因此我无法将图像传递到CIImage以简化坐标转换。以下是我的配置示例，任何想法如何转换为可用的CGRect？

func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {

    let imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)
    let opaqueBuffer = Unmanaged<CVImageBuffer>.passUnretained(imageBuffer!).toOpaque()
    let pixelBuffer = Unmanaged<CVPixelBuffer>.fromOpaque(opaqueBuffer).takeUnretainedValue()
    let sourceImage = CIImage(cvPixelBuffer: pixelBuffer)
    let features = self.faceDetector!.features(in: sourceImage, options: options)

    if (features.count != 0) {
        let faceImage = sourceImage
        let faceDetector = CIDetector(ofType: CIDetectorTypeFace, context: nil, options: [CIDetectorAccuracy: CIDetectorAccuracyHigh])
        let faces = faceDetector?.features(in: faceImage) as! [CIFaceFeature]

        let transformScale = CGAffineTransform(scaleX: 1, y: -1)
        let transform = transformScale.translatedBy(x: 0, y: -faceImage.extent.height)
        for feature in features as! [CIFaceFeature] {

            faceBounds = feature.bounds

            var fb = faceBounds?.applying(transform)
            // imageViewSize is the screen frame
            let scale = min(imageViewSize.width / fb!.width,
                            imageViewSize.height / fb!.height)

            let dx = (imageViewSize.width - fb!.width * scale) / 2
            let dy = (imageViewSize.height - fb!.height * scale) / 2

            fb?.applying(CGAffineTransform(scaleX: scale, y: scale))
            fb?.origin.x += dx
            fb?.origin.y += dy

            realFaceRect = fb // COMPLETELY WRONG :'(
    }
}

Answer 1

如果有人遇到同样的问题。这是一个简单的解决方案

let imgHeight = CGFloat(CVPixelBufferGetHeight(pixelBuffer))
let ratio = self.view.frame.width / self.visage!.imgHeight

func convertFrame(frame: CGRect, ratio: CGFloat) -> CGRect {
    let x = frame.origin.y * ratio
    let y = frame.origin.x * ratio
    let width = frame.height * ratio
    let height = frame.width * ratio
    return CGRect(x: x, y: y, width: width, height: height)
}

func convertPoint(point: CGPoint, ratio: CGFloat) -> CGPoint {
    let x = point.y * ratio
    let y = point.x * ratio
    return CGPoint(x: x, y: y)
}

从CIFaceFeature将CIImage坐标转换为CGRect

1 个答案: