iOS利用CoreImage实现人脸识别详解

import UIKit
import CoreImage // 引入CoreImage
class ViewController: UIViewController {
 @IBOutlet weak var personPic: UIImageView!

 override func viewDidLoad() {
 super.viewDidLoad()

 personPic.image = UIImage(named: "face-1")
 // 调用detect
 detect()

 }
 //MARK: - 识别面部
 func detect() {
 // 创建personciImage变量保存从故事板中的UIImageView提取图像并将其转换为CIImage，使用Core Image时需要用CIImage
 guard let personciImage = CIImage(image: personPic.image!) else {
  return
 }
 // 创建accuracy变量并设为CIDetectorAccuracyHigh，可以在CIDetectorAccuracyHigh(较强的处理能力)与CIDetectorAccuracyLow(较弱的处理能力)中选择，因为想让准确度高一些在这里选择CIDetectorAccuracyHigh
 let accuracy = [CIDetectorAccuracy: CIDetectorAccuracyHigh]
 // 这里定义了一个属于CIDetector类的faceDetector变量，并输入之前创建的accuracy变量
 let faceDetector = CIDetector(ofType: CIDetectorTypeFace, context: nil, options: accuracy)
 // 调用faceDetector的featuresInImage方法，识别器会找到所给图像中的人脸，最后返回一个人脸数组
 let faces = faceDetector?.features(in: personciImage)
 // 循环faces数组里的所有face，并将识别到的人脸强转为CIFaceFeature类型
 for face in faces as! [CIFaceFeature] {

  print("Found bounds are (face.bounds)")
  // 创建名为faceBox的UIView，frame设为返回的faces.first的frame，绘制一个矩形框来标识识别到的人脸
  let faceBox = UIView(frame: face.bounds)
  // 设置faceBox的边框宽度为3
  faceBox.layer.borderWidth = 3
  // 设置边框颜色为红色
  faceBox.layer.borderColor = UIColor.red.cgColor
  // 将背景色设为clear，意味着这个视图没有可见的背景
  faceBox.backgroundColor = UIColor.clear
  // 最后，把这个视图添加到personPic imageView上
  personPic.addSubview(faceBox)
  // API不仅可以帮助你识别人脸，也可识别脸上的左右眼，我们不在图像中标识出眼睛，只是给你展示一下CIFaceFeature的相关属性
  if face.hasLeftEyePosition {
  print("Left eye bounds are (face.leftEyePosition)")
  }

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

Found bounds are (314.0, 243.0, 196.0, 196.0)

func detect1() {

 guard let personciImage = CIImage(image: personPic.image!) else { return }
 let accuracy = [CIDetectorAccuracy: CIDetectorAccuracyHigh]
 let faceDetector = CIDetector(ofType: CIDetectorTypeFace, context: nil, options: accuracy)
 let faces = faceDetector?.features(in: personciImage)

 // 转换坐标系
 let ciImageSize = personciImage.extent.size
 var transform = CGAffineTransform(scaleX: 1, y: -1)
 transform = transform.translatedBy(x: 0, y: -ciImageSize.height)

 for face in faces as! [CIFaceFeature] {
 print("Found bounds are (face.bounds)") 
 // 应用变换转换坐标
 var faceViewBounds = face.bounds.applying(transform)
 // 在图像视图中计算矩形的实际位置和大小
 let viewSize = personPic.bounds.size
 let scale = min(viewSize.width / ciImageSize.width, viewSize.height / ciImageSize.height)
 let offsetX = (viewSize.width - ciImageSize.width * scale) / 2
 let offsetY = (viewSize.height - ciImageSize.height * scale) / 2

 faceViewBounds = faceViewBounds.applying(CGAffineTransform(scaleX: scale, y: scale))
 faceViewBounds.origin.x += offsetX
 faceViewBounds.origin.y += offsetY

 let faceBox = UIView(frame: faceViewBounds)
 faceBox.layer.borderWidth = 3
 faceBox.layer.borderColor = UIColor.red.cgColor
 faceBox.backgroundColor = UIColor.clear
 personPic.addSubview(faceBox)

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

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

class CameraViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
 @IBOutlet var imageView: UIImageView!
 let imagePicker = UIImagePickerController()

 override func viewDidLoad() {
  super.viewDidLoad()
  imagePicker.delegate = self
 }

 @IBAction func takePhoto(_ sender: AnyObject) {

  if !UIImagePickerController.isSourceTypeAvailable(.camera) {
   return
  }

  imagePicker.allowsEditing = false
  imagePicker.sourceType = .camera

  present(imagePicker, animated: true, completion: nil)
 }

 func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {

  if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
   imageView.contentMode = .scaleAspectFit
   imageView.image = pickedImage
  }

  dismiss(animated: true, completion: nil)
  self.detect()
 }

 func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
  dismiss(animated: true, completion: nil)
 }
}

func detect() {
 let imageOptions = NSDictionary(object: NSNumber(value: 5) as NSNumber, forKey: CIDetectorImageOrientation as NSString)
 let personciImage = CIImage(cgImage: imageView.image!.cgImage!)
 let accuracy = [CIDetectorAccuracy: CIDetectorAccuracyHigh]
 let faceDetector = CIDetector(ofType: CIDetectorTypeFace, context: nil, options: accuracy)
 let faces = faceDetector?.features(in: personciImage, options: imageOptions as? [String : AnyObject])

 if let face = faces?.first as? CIFaceFeature {
  print("found bounds are (face.bounds)")

  let alert = UIAlertController(title: "提示", message: "检测到了人脸", preferredStyle: UIAlertControllerStyle.alert)
  alert.addAction(UIAlertAction(title: "确定", style: UIAlertActionStyle.default, handler: nil))
  self.present(alert, animated: true, completion: nil)

  if face.hasSmile {
   print("face is smiling");
  }

  if face.hasLeftEyePosition {
   print("左眼的位置: (face.leftEyePosition)")
  }

  if face.hasRightEyePosition {
   print("右眼的位置: (face.rightEyePosition)")
  }
 } else {
  let alert = UIAlertController(title: "提示", message: "未检测到人脸", preferredStyle: UIAlertControllerStyle.alert)
  alert.addAction(UIAlertAction(title: "确定", style: UIAlertActionStyle.default, handler: nil))
  self.present(alert, animated: true, completion: nil)
 }
}

if (face.hasMouthPosition) {
 print("mouth detected")
}