[iOS 8]CIQRCodeFeatureを使って画像からQRコードを解析する

import UIKit

class ViewController: UIViewController, UINavigationControllerDelegate, UIImagePickerControllerDelegate {
    /** 写真表示用ImageView */
    @IBOutlet weak var photoImageView: UIImageView!
    /** QRコードの読取りテキストを表示 */
    @IBOutlet weak var messageTextView: UITextView!
    /** 画像取得用 */
    var picker:UIImagePickerController?
    /** 画像認識用 */
    var detector:CIDetector?
    
    override func viewDidLoad()
    {
        super.viewDidLoad()
        detector = CIDetector(ofType: CIDetectorTypeQRCode, context: nil, options: [CIDetectorAccuracy:CIDetectorAccuracyHigh])
        picker = UIImagePickerController()
        picker!.delegate = self
        picker!.allowsEditing = false
        messageTextView.resignFirstResponder()
    }
    /**
    * アルバムボタンをタップ
    */
    @IBAction func onTapAlbumButton(sender: AnyObject)
    {
        //ライブラリが使用できるかどうか判定
        if(UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.PhotoLibrary))
        {
            self.presentViewController(picker!, animated: true, completion: nil)
        }
    }
    /**
    * 写真選択
    */
    func imagePickerController(picker: UIImagePickerController!, didFinishPickingImage image: UIImage!, editingInfo: NSDictionary!){
        self.dismissViewControllerAnimated(true, completion: nil)
        //画面に写真を表示
        photoImageView.image = image
        //画像を変換
        var ciImage:CIImage = CIImage(image: image)
        var message:String = "";
        //画像内にQRコードがあるか調べる
        let features = detector?.featuresInImage(ciImage)
        for feature in features as [CIQRCodeFeature] {
            message += feature.messageString
        }
        //テキストに表示
        if(message == "") {
            messageTextView.text = "[QRコードは検出されませんでした]";
        } else {
            messageTextView.text = message;
        }
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

//画像を変換
var ciImage:CIImage = CIImage(image: image)

//画像内にQRコードがあるか調べる
let features = detector?.featuresInImage(ciImage)
for feature in features as [CIQRCodeFeature] {
    message += feature.messageString
}