Apple Vision framework – Text extraction from image

Question

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

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

Answer 1

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 works starting from iOS 13.0 and macOS 10.15.

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
        }
    }
}

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])