detectFaces

// storyboardに置いたimageViewからCIImageを生成する
let image  = CIImage(CGImage: self.sampleImageView.image?.CGImage)
            
// 顔認識なのでTypeをCIDetectorTypeFaceに指定する
let detector = CIDetector(ofType: CIDetectorTypeFace, context: nil, options: [CIDetectorAccuracy: CIDetectorAccuracyHigh])
            
// 取得するパラメーターを指定する
let options = [CIDetectorSmile : true, CIDetectorEyeBlink : true]
            
// 画像から特徴を抽出する
let features = detector.featuresInImage(image, options: options)
            
var resultString: NSMutableString = "DETECTED FACES:\n\n"
            
for feature in features as [CIFaceFeature] {
    resultString.appendFormat("bounds:%@\n", NSStringFromCGRect(feature.bounds))
    resultString.appendFormat("hasSmile: %@\n\n", feature.hasSmile ? "YES" : "NO")
    // resultString.appendFormat("faceAngle: %@", feature.hasFaceAngle ? feature.faceAngle : "NONE");
    // resultString.appendFormat("leftEyeClosed: %@", feature.leftEyeClosed ? "YES" : "NO");
    // resultString.appendFormat("rightEyeClosed: %@", feature.rightEyeClosed ? "YES" : "NO");
}