如何检查图像中是否没有文本--MLKit VisionCloudTextRecognizer答案

【问题标题】：How to check if there is no text in an Image--MLKit VisionCloudTextRecognizer如何检查图像中是否没有文本--MLKit VisionCloudTextRecognizer
【发布时间】：2019-06-24 11:47:11
【问题描述】：

我有一个名为 MLVision 的类来处理文本识别。

class MLVision {

    lazy var vision = Vision.vision()
    var textRecognizer: VisionTextRecognizer!
    var textArray = [] as Array<String>
    var lineText :String = ""

    func startRecognising(image : UIImage,completion: @escaping (_ result: [String]) -> ()){

        let visionImage = VisionImage(image: image)

        let options = VisionCloudTextRecognizerOptions()
        options.languageHints = ["en","hi"]
        textRecognizer = vision.cloudTextRecognizer(options: options)

        textRecognizer.process(visionImage, completion: { (features, error) in
            guard error == nil, let features = features else {
                print("No text Found!!")
                return
            }

            for block in features.blocks {
                for line in block.lines{


                    self.lineText = line.text
                    self.separate(lineText: self.lineText)

                }
            }
            completion(self.textArray)
        })
    }

    func separate(lineText : String){
        let separators = CharacterSet(charactersIn: (":)(,•/·]["))
        let ofWordsArray = lineText.components(separatedBy: separators)

        for word in ofWordsArray{

            let low = word.trimmingCharacters(in: .whitespacesAndNewlines).lowercased()
            if low != ""{
                textArray.append(low)
            }
        }
    }
}

这就是我称之为 Mlvision 类的 ViewController。

let mlVision = MLVision()

override func viewDidLoad() {
        super.viewDidLoad()
    mlVision.startRecognising(image: croppedImage!){ result in

                self.textArray = result
                self.searchIngredients(textArray: self.textArray)
        }
}

所以基本上我的应用程序会识别文本，然后将其分隔并以数组的形式传递。

如果我检查没有文字的图像以显示警报，我想处理。我知道 guard error == nil, let features = features else {return} 处理它，但我想从我的 ViewController 中检查它。有没有办法做到这一点？

【问题讨论】：

标签： ios swift firebase firebase-mlkit text-recognition

【解决方案1】：

如果我的问题是正确的 - 你只是想在你开始它的范围内处理识别错误，如果是这样，你可以使用 Result 将你的代码修改为下面的代码。

// add your own Errors
enum RecognitionError: Error {
    case textNotFound
}

//modify `completion` closure by passing `Result` object instead of array
func startRecognising(image : UIImage,
                  completion: @escaping (_ result: Result<[String], RecognitionError>) -> ()){

    let visionImage = VisionImage(image: image)

    let options = VisionCloudTextRecognizerOptions()
    options.languageHints = ["en","hi"]
    textRecognizer = vision.cloudTextRecognizer(options: options)

    textRecognizer.process(visionImage, completion: { (features, error) in
        guard error == nil, let features = features else {
            print("No text Found!!")
            completion(.failure(.textNotFound))
            return
        }

        for block in features.blocks {
            for line in block.lines{


                self.lineText = line.text
                self.separate(lineText: self.lineText)

            }
        }
        completion(.success(self.textArray))
    })
}

并在您的 ViewController 中处理它：

override func viewDidLoad() {
    super.viewDidLoad()
    mlVision.startRecognising(image: croppedImage!){ result in
        switch result {

        case .success(let array):
            self.textArray = result
            self.searchIngredients(textArray: self.textArray)

        case .failure(let error):
            print(error)
        }
    }
}

【讨论】：