swift - 如何从 iOS 11 和 Swift 4 中的相机捕获深度数据？

Question

我正在尝试使用 AVDepthData 从 iOS 11 中的相机获取深度数据，但是当我使用 AVCapturePhotoCaptureDelegate 设置 photoOutput 时，photo.depthData 为 nil。

所以我尝试使用 AVCaptureDepthDataOutput 设置 AVCaptureDepthDataOutputDelegate，但我不知道如何捕捉深度照片？

有人从 AVDepthData 得到过图像吗？

编辑:

这是我试过的代码:

// delegates: AVCapturePhotoCaptureDelegate & AVCaptureDepthDataOutputDelegate

@IBOutlet var image_view: UIImageView!
@IBOutlet var capture_button: UIButton!

var captureSession: AVCaptureSession?
var sessionOutput: AVCapturePhotoOutput?
var depthOutput: AVCaptureDepthDataOutput?
var previewLayer: AVCaptureVideoPreviewLayer?

@IBAction func capture(_ sender: Any) {

    self.sessionOutput?.capturePhoto(with: AVCapturePhotoSettings(format: [AVVideoCodecKey: AVVideoCodecType.jpeg]), delegate: self)

}

func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {

    self.previewLayer?.removeFromSuperlayer()
    self.image_view.image = UIImage(data: photo.fileDataRepresentation()!)

    let depth_map = photo.depthData?.depthDataMap
    print("depth_map:", depth_map) // is nil

}

func depthDataOutput(_ output: AVCaptureDepthDataOutput, didOutput depthData: AVDepthData, timestamp: CMTime, connection: AVCaptureConnection) {

    print("depth data") // never called

}

override func viewDidLoad() {
    super.viewDidLoad()

    self.captureSession = AVCaptureSession()
    self.captureSession?.sessionPreset = .photo

    self.sessionOutput = AVCapturePhotoOutput()
    self.depthOutput = AVCaptureDepthDataOutput()
    self.depthOutput?.setDelegate(self, callbackQueue: DispatchQueue(label: "depth queue"))

    do {

        let device = AVCaptureDevice.default(for: .video)
        let input = try AVCaptureDeviceInput(device: device!)
        if(self.captureSession?.canAddInput(input))!{
            self.captureSession?.addInput(input)

            if(self.captureSession?.canAddOutput(self.sessionOutput!))!{
                self.captureSession?.addOutput(self.sessionOutput!)


                if(self.captureSession?.canAddOutput(self.depthOutput!))!{
                    self.captureSession?.addOutput(self.depthOutput!)

                    self.previewLayer = AVCaptureVideoPreviewLayer(session: self.captureSession!)
                    self.previewLayer?.frame = self.image_view.bounds
                    self.previewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
                    self.previewLayer?.connection?.videoOrientation = AVCaptureVideoOrientation.portrait
                    self.image_view.layer.addSublayer(self.previewLayer!)

                }

            }

        }

    } catch {}

    self.captureSession?.startRunning()

}

我正在尝试两件事，一件是深度数据为零，另一件是我尝试调用深度委托(delegate)方法。

有人知道我错过了什么吗？

Answer 1

首先，你需要使用双摄像头，否则你将得不到任何深度数据。

let device = AVCaptureDevice.default(.builtInDualCamera, for: .video, position: .back)

并保留对队列的引用

let dataOutputQueue = DispatchQueue(label: "data queue", qos: .userInitiated, attributes: [], autoreleaseFrequency: .workItem)

您可能还想同步视频和深度数据

var outputSynchronizer: AVCaptureDataOutputSynchronizer?

然后您可以像这样在 viewDidLoad() 方法中同步两个输出

if sessionOutput?.isDepthDataDeliverySupported {
    sessionOutput?.isDepthDataDeliveryEnabled = true
    depthDataOutput?.connection(with: .depthData)!.isEnabled = true
    depthDataOutput?.isFilteringEnabled = true
    outputSynchronizer = AVCaptureDataOutputSynchronizer(dataOutputs: [sessionOutput!, depthDataOutput!])
    outputSynchronizer!.setDelegate(self, queue: self.dataOutputQueue)
}

我建议观看 WWDC session 507 - 他们还提供了一个完整的示例应用程序，可以完全满足您的需求。

https://developer.apple.com/videos/play/wwdc2017/507/