• 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
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