Apple Vision框架–从图像中提取文本 [英] Apple Vision framework – Text extraction from image

问题描述

我正在使用iOS 11的Vision框架来检测图像上的文本.

I am using Vision framework for iOS 11 to detect text on image.

已成功检测到文本，但是如何获取检测到的文本?

The texts are getting detected successfully, but how we can get the detected text?

推荐答案

在Apple Vision中，您可以使用 VNRecognizeTextRequest 类轻松地从图像中提取文本，您提出图像分析请求，以发现并识别图像中的文本.

In Apple Vision you can easily extract text from image using VNRecognizeTextRequest class, allowing you to make an image analysis request that finds and recognizes text in an image.

VNRecognizeTextRequest从iOS 13.0和macOS 10.15开始运行.

VNRecognizeTextRequest works starting from iOS 13.0 and macOS 10.15.

下面是一个代码片段，向您展示如何操作:

Here's a code snippet showing you how to do it:

let requestHandler = VNImageRequestHandler(url: imageURL, options: [:])

let request = VNRecognizeTextRequest { (request, error) in

    guard let observations = request.results as? [VNRecognizedTextObservation] 
    else { return }

    for observation in observations {

        let topCandidate: [VNRecognizedText] = observation.topCandidates(1)

        if let recognizedText: VNRecognizedText = topCandidate.first {
            label.text = recognizedText.string
        }
    }
}

然后，您必须为recognitionLevel实例属性分配一个值:

Then you have to assign a value for recognitionLevel instance property:

// non-realtime asynchronous but accurate text recognition
request.recognitionLevel = VNRequestTextRecognitionLevel.accurate

// nearly realtime but not-accurate text recognition
request.recognitionLevel = VNRequestTextRecognitionLevel.fast

try? requestHandler.perform([request])

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