CIDetector未检测到QRCodes

Question

为了从UIImage中提取messageString，我尝试使用CIDetector从CIDetector中检测出messageString。

我有一个函数，它基本上接收一个UIImage作为输入，并返回解码的messageString。

我传递给这个函数的UIImage是使用PHAsset、PHAssetCollection、PHImageRequestOptions等从用户库中提取出来的。请求是同步提出的，我得到的所有图像质量都很好(为了确保图像的可读性，我尝试在UIImageView中呈现图像)。

在这里，您可以看到请求图像的代码片段：

let _: PHImageRequestID = PHImageManager.defaultManager().requestImageForAsset(asset as! PHAsset, targetSize: size, contentMode: PHImageContentMode.AspectFit, options: options, resultHandler: { (image: UIImage?, info:[NSObject : AnyObject]?) -> Void in
                    images.append(image!)
                })

获取图像后，我想检测QRCodes，并使用以下代码：

func scanImage(image: CIImage) -> String {

    let detector = CIDetector(ofType: CIDetectorTypeQRCode, context: nil, options: [CIDetectorAccuracy:CIDetectorAccuracyHigh])
    var image = CIImage(image: uiimage)

    var decode = ""
    let features = detector.featuresInImage(image!)
    for feature in features as! [CIQRCodeFeature] {
        decode = feature.messageString
    }
    return decode
}

我发现了这个(Core Image Detector(CIDetector) is not detecting QRCodes)和其他类似的问题，但它们似乎都不起作用。

这是我遵循https://www.shinobicontrols.com/blog/ios8-day-by-day-day-13-coreimage-detectors的教程

我做错了什么吗？

提前感谢

Answer 1

问题是您要在函数中传递CIImage

func scanImage(image: CIImage)

中添加另一个具有未定义图像的图像变量。

var image = CIImage(image: uiimage)

删除这一行，这应该是可以的，我正在为自己编写一个QRCode，如果您感兴趣，您可以查看它。

// open photo library 
func loadGallery() {
    let imagePicker = UIImagePickerController()
    imagePicker.delegate = self
    imagePicker.sourceType = .PhotoLibrary
    self.presentViewController(imagePicker,
        animated: true,
        completion: nil)
}

// read QRCode from selecting image
func imagePickerController(picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : AnyObject]) {
    let qrImg:UIImage = info[UIImagePickerControllerOriginalImage] as! UIImage

    if #available(iOS 8.0, *) {
        let detector:CIDetector = CIDetector(ofType: CIDetectorTypeQRCode, context:nil, options:[CIDetectorAccuracy: CIDetectorAccuracyHigh])
        let ciimg: CIImage = CIImage(image: qrImg)!
        let features = detector.featuresInImage(ciimg)

        for feature in features as! [CIQRCodeFeature] {
            print(feature.messageString)
        }


    } else {
        // Fallback on earlier versions
    }

    dismissViewControllerAnimated(true, completion: nil)
}

更新到Swift 3 xcode 8.1

// read QRCode from selecting image
func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {


    let qrImg:UIImage = info[UIImagePickerControllerOriginalImage] as! UIImage

    if #available(iOS 8.0, *) {
        let detector:CIDetector = CIDetector(ofType: CIDetectorTypeQRCode, context:nil, options:[CIDetectorAccuracy: CIDetectorAccuracyHigh])!
        let ciimg: CIImage = CIImage(image: qrImg)!
        let features = detector.features(in: ciimg)

        for feature in features as! [CIQRCodeFeature] {
            print(feature.messageString!)
        }


    } else {
        // Fallback on earlier versions
    }
    dismiss(animated: true, completion: nil)
}

希望这会有帮助