iOS相机面部跟踪（Swift 3 Xcode 8）

我正在试图制作一个简单的相机应用程序，其中前置相机可以检测到人脸。这应该是很简单：iOS相机面部跟踪（Swift 3 Xcode 8）

创建从UIImage的继承CameraView类，并将其放置在UI中。确保它实现AVCaptureVideoDataOutputSampleBufferDelegate以实时处理相机中的帧。
```
class CameraView: UIImageView, AVCaptureVideoDataOutputSampleBufferDelegate 
```

在函数handleCamera，当CameraView被实例调用，建立一个AVCapture会话。从相机添加输入。

override init(frame: CGRect) { 
    super.init(frame:frame) 

    handleCamera() 
} 

func handleCamera() { 
    camera = AVCaptureDevice.defaultDevice(withDeviceType: .builtInWideAngleCamera, 
              mediaType: AVMediaTypeVideo, position: .front) 
    session = AVCaptureSession() 

    // Set recovered camera as an input device for the capture session 
    do { 
     try input = AVCaptureDeviceInput(device: camera); 
    } catch _ as NSError { 
     print ("ERROR: Front camera can't be used as input") 
     input = nil 
    } 

    // Add the input from the camera to the capture session 
    if (session?.canAddInput(input) == true) { 
     session?.addInput(input) 
    }

创建输出。创建一个串行输出队列来传递将由AVCaptureVideoDataOutputSampleBufferDelegate处理的数据（本例中为类本身）。将输出添加到会话。

output = AVCaptureVideoDataOutput() 

    output?.alwaysDiscardsLateVideoFrames = true  
    outputQueue = DispatchQueue(label: "outputQueue") 
    output?.setSampleBufferDelegate(self, queue: outputQueue) 

    // add front camera output to the session for use and modification 
    if(session?.canAddOutput(output) == true){ 
     session?.addOutput(output) 
    } // front camera can't be used as output, not working: handle error 
    else { 
     print("ERROR: Output not viable") 
    }

设置相机预览视图，执行会话

// Setup camera preview with the session input 
    previewLayer = AVCaptureVideoPreviewLayer(session: session) 
    previewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill 
    previewLayer?.connection.videoOrientation = AVCaptureVideoOrientation.portrait 
    previewLayer?.frame = self.bounds 
    self.layer.addSublayer(previewLayer!) 

    // Process the camera and run it onto the preview 
    session?.startRunning()

在通过委托运行captureOutput功能

，所述收到样品缓冲液转换为CIImage以检测人脸。如果发现脸部，请提供反馈。

func captureOutput(_ captureOutput: AVCaptureOutput!, didDrop sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) { 

let pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) 
let cameraImage = CIImage(cvPixelBuffer: pixelBuffer!) 


let accuracy = [CIDetectorAccuracy: CIDetectorAccuracyHigh] 
let faceDetector = CIDetector(ofType: CIDetectorTypeFace, context: nil, options: accuracy) 
let faces = faceDetector?.features(in: cameraImage) 

for face in faces as! [CIFaceFeature] { 

     print("Found bounds are \(face.bounds)") 

     let faceBox = UIView(frame: face.bounds) 

     faceBox.layer.borderWidth = 3 
     faceBox.layer.borderColor = UIColor.red.cgColor 
     faceBox.backgroundColor = UIColor.clear 
     self.addSubview(faceBox) 

     if face.hasLeftEyePosition { 
      print("Left eye bounds are \(face.leftEyePosition)") 
     } 

     if face.hasRightEyePosition { 
      print("Right eye bounds are \(face.rightEyePosition)") 
     } 
    } 
}

我的问题：我可以运行，但与我从所有在互联网上尝试不同的代码的群众，我从来没有能够得到captureOutput检测面对镜头。要么是应用程序没有进入函数，要么是因为变量不起作用而崩溃，最常见的情况是sampleBuffer变量为nul。我在做什么错？

来源

2017-04-13 KazToozs

您需要更改captureOutput功能参数如下：当缓冲下降，而不是当它从相机获取func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!)

你captureOutput函数调用。

来源

2017-05-22 00:25:09

我实际上在iOS实验室的帮助下发现了这个问题，忘记了更新问题。这实际上是所有失踪，谢谢你通过，希望这会帮助别人。 – KazToozs

iOS相机面部跟踪（Swift 3 Xcode 8）

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