swift通过摄像头读取每一帧的图片，并且做识别做人脸识别

最近帮别人做一个项目，主要是使用摄像头做人脸识别

github地址：https://github.com/qugang/AVCaptureVideoTemplate

要使用IOS的摄像头，需要使用AVFoundation 库，库里面的东西我就不介绍。

启动摄像头需要使用AVCaptureSession 类。

然后得到摄像头传输的每一帧数据，需要使用AVCaptureVideoDataOutputSampleBufferDelegate 委托。

首先在viewDidLoad 里添加找摄像头设备的代码，找到摄像头设备以后，开启摄像头

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captureSession.sessionPreset = AVCaptureSessionPresetLow
let devices = AVCaptureDevice.devices()
for device in devices {
  if (device.hasMediaType(AVMediaTypeVideo)) {
    if (device.position == AVCaptureDevicePosition.Front) {
      captureDevice = device as?AVCaptureDevice
      if captureDevice != nil {
        println("Capture Device found")
        beginSession()
      }
    }
  }
}

beginSession,开启摄像头：

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func beginSession() {
  var err : NSError? = nil
  captureSession.addInput(AVCaptureDeviceInput(device: captureDevice, error: &err))
  let output = AVCaptureVideoDataOutput()
  let cameraQueue = dispatch_queue_create("cameraQueue", DISPATCH_QUEUE_SERIAL)
  output.setSampleBufferDelegate(self, queue: cameraQueue)
  output.videoSettings = [kCVPixelBufferPixelFormatTypeKey: kCVPixelFormatType_32BGRA]
  captureSession.addOutput(output)
  if err != nil {
    println("error: (err?.localizedDescription)")
  }
  previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
  previewLayer?.videoGravity = "AVLayerVideoGravityResizeAspect"
  previewLayer?.frame = self.view.bounds
  self.view.layer.addSublayer(previewLayer)
  captureSession.startRunning()
}

开启以后，实现captureOutput 方法：

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func captureOutput(captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, fromConnection connection: AVCaptureConnection!) {
  if(self.isStart)
  {
    let resultImage = sampleBufferToImage(sampleBuffer)
    let context = CIContext(options:[kCIContextUseSoftwareRenderer:true])
    let detecotr = CIDetector(ofType:CIDetectorTypeFace,  context:context, options:[CIDetectorAccuracy: CIDetectorAccuracyHigh])
    let ciImage = CIImage(image: resultImage)
    let results:NSArray = detecotr.featuresInImage(ciImage,options: ["CIDetectorImageOrientation" : 6])
    for r in results {
      let face:CIFaceFeature = r as! CIFaceFeature;
      let faceImage = UIImage(CGImage: context.createCGImage(ciImage, fromRect: face.bounds),scale: 1.0, orientation: .Right)
      NSLog("Face found at (%f,%f) of dimensions %fx%f", face.bounds.origin.x, face.bounds.origin.y,pickUIImager.frame.origin.x, pickUIImager.frame.origin.y)
      dispatch_async(dispatch_get_main_queue()) {
        if (self.isStart)
        {
          self.dismissViewControllerAnimated(true, completion: nil)
          self.didReceiveMemoryWarning()
          self.callBack!(face: faceImage!)
        }
        self.isStart = false
      }
    }
  }
}

在每一帧图片上使用CIDetector 得到人脸，CIDetector 还可以得到眨眼，与微笑的人脸，如果要详细使用去官方查看API

上面就是关键代码，设置了有2秒的延迟，2秒之后开始人脸检测。

全部代码：

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//
//  ViewController.swift
//  AVSessionTest
//
//  Created by qugang on 15/7/8.
//  Copyright (c) 2015年 qugang. All rights reserved.
//
 
import UIKit
import AVFoundation
class AVCaptireVideoPicController: UIViewController,AVCaptureVideoDataOutputSampleBufferDelegate {
  var callBack :((face: UIImage) ->())?
  let captureSession = AVCaptureSession()
  var captureDevice : AVCaptureDevice?
  var previewLayer : AVCaptureVideoPreviewLayer?
  var pickUIImager : UIImageView = UIImageView(image: UIImage(named: "pick_bg"))
  var line : UIImageView = UIImageView(image: UIImage(named: "line"))
  var timer : NSTimer!
  var upOrdown = true
  var isStart = false
  override func viewDidLoad() {
    super.viewDidLoad()
    captureSession.sessionPreset = AVCaptureSessionPresetLow
    let devices = AVCaptureDevice.devices()
    for device in devices {
      if (device.hasMediaType(AVMediaTypeVideo)) {
        if (device.position == AVCaptureDevicePosition.Front) {
          captureDevice = device as?AVCaptureDevice
          if captureDevice != nil {
            println("Capture Device found")
            beginSession()
          }
        }
      }
    }
    pickUIImager.frame = CGRect(x: self.view.bounds.width / 2 - 100, y: self.view.bounds.height / 2 - 100, 200,height: 200)
    line.frame = CGRect(x: self.view.bounds.width / 2 - 100, y: self.view.bounds.height / 2 - 100, 200, height: 2)
    self.view.addSubview(pickUIImager)
    self.view.addSubview(line)
    timer =  NSTimer.scheduledTimerWithTimeInterval(0.01, target: self, selector: "animationSate", userInfo: nil, repeats: true)
     
    NSTimer.scheduledTimerWithTimeInterval(2, target: self, selector: "isStartTrue", userInfo: nil, repeats: false)
  }
  func isStartTrue(){
    self.isStart = true
  }
  override func didReceiveMemoryWarning(){
    super.didReceiveMemoryWarning()
    captureSession.stopRunning()
  }
   
  func animationSate(){
    if upOrdown {
      if (line.frame.origin.y >= pickUIImager.frame.origin.y + 200)
      {
        upOrdown = false
      }
      else
      {
        line.frame.origin.y += 2
      }
    } else {
      if (line.frame.origin.y <= pickUIImager.frame.origin.y)
      {
        upOrdown = true
      }
      else
      {
        line.frame.origin.y -= 2
      }
    }
  }
  func beginSession() {
    var err : NSError? = nil
    captureSession.addInput(AVCaptureDeviceInput(device: captureDevice, error: &err))
    let output = AVCaptureVideoDataOutput()
    let cameraQueue = dispatch_queue_create("cameraQueue", DISPATCH_QUEUE_SERIAL)
    output.setSampleBufferDelegate(self, queue: cameraQueue)
    output.videoSettings = [kCVPixelBufferPixelFormatTypeKey: kCVPixelFormatType_32BGRA]
    captureSession.addOutput(output)
    if err != nil {
      println("error: (err?.localizedDescription)")
    }
    previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
    previewLayer?.videoGravity = "AVLayerVideoGravityResizeAspect"
    previewLayer?.frame = self.view.bounds
    self.view.layer.addSublayer(previewLayer)
    captureSession.startRunning()
  }
  func captureOutput(captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, fromConnection connection: AVCaptureConnection!) {
    if(self.isStart)
    {
      let resultImage = sampleBufferToImage(sampleBuffer)
      let context = CIContext(options:[kCIContextUseSoftwareRenderer:true])
      let detecotr = CIDetector(ofType:CIDetectorTypeFace,  context:context, options:[CIDetectorAccuracy: CIDetectorAccuracyHigh])
      let ciImage = CIImage(image: resultImage)
      let results:NSArray = detecotr.featuresInImage(ciImage,options: ["CIDetectorImageOrientation" : 6])
      for r in results {
        let face:CIFaceFeature = r as! CIFaceFeature;
        let faceImage = UIImage(CGImage: context.createCGImage(ciImage, fromRect: face.bounds),scale: 1.0, orientation: .Right)
        NSLog("Face found at (%f,%f) of dimensions %fx%f", face.bounds.origin.x, face.bounds.origin.y,pickUIImager.frame.origin.x, pickUIImager.frame.origin.y)
        dispatch_async(dispatch_get_main_queue()) {
          if (self.isStart)
          {
            self.dismissViewControllerAnimated(true, completion: nil)
            self.didReceiveMemoryWarning()
            self.callBack!(face: faceImage!)
          }
          self.isStart = false
        }
      }
    }
  }
  private func sampleBufferToImage(sampleBuffer: CMSampleBuffer!) -> UIImage {
    let imageBuffer: CVImageBufferRef = CMSampleBufferGetImageBuffer(sampleBuffer)
    CVPixelBufferLockBaseAddress(imageBuffer, 0)
    let baseAddress = CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 0)
    let bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer)
    let width = CVPixelBufferGetWidth(imageBuffer)
    let height = CVPixelBufferGetHeight(imageBuffer)
    let colorSpace: CGColorSpaceRef = CGColorSpaceCreateDeviceRGB()
    let bitsPerCompornent = 8
    var bitmapInfo = CGBitmapInfo((CGBitmapInfo.ByteOrder32Little.rawValue | CGImageAlphaInfo.PremultipliedFirst.rawValue) as UInt32)
    let newContext = CGBitmapContextCreate(baseAddress, width, height, bitsPerCompornent, bytesPerRow, colorSpace, bitmapInfo) as CGContextRef
    let imageRef: CGImageRef = CGBitmapContextCreateImage(newContext)
    let resultImage = UIImage(CGImage: imageRef, scale: 1.0, orientation: UIImageOrientation.Right)!
    return resultImage
  }
  func imageResize (imageObj:UIImage, sizeChange:CGSize)-> UIImage{
    let hasAlpha = false
    let scale: CGFloat = 0.0
     
    UIGraphicsBeginImageContextWithOptions(sizeChange, !hasAlpha, scale)
    imageObj.drawInRect(CGRect(origin: CGPointZero, size: sizeChange))
    let scaledImage = UIGraphicsGetImageFromCurrentImageContext()
    return scaledImage
  }
}
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原文地址：https://www.cnblogs.com/Free-Thinker/p/5106330.html