imageclassifier-coreml2-vision.swift

func imageClassifier(image: UIImage, wordNumber: Int, characterNumber: Int, currentObservation : VNTextObservation){
        let request = VNCoreMLRequest(model: model) { [weak self] request, error in
            guard let results = request.results as? [VNClassificationObservation],
                let topResult = results.first else {
                    fatalError("Unexpected result type from VNCoreMLRequest")
            }
            let result = topResult.identifier
            let classificationInfo: [String: Any] = ["wordNumber" : wordNumber,
                                                     "characterNumber" : characterNumber,
                                                     "class" : result]
            self?.handleResult(classificationInfo, currentObservation: currentObservation)
        }
        guard let ciImage = CIImage(image: image) else {
            fatalError("Could not convert UIImage to CIImage :(")
        }
        let handler = VNImageRequestHandler(ciImage: ciImage)
        DispatchQueue.global(qos: .userInteractive).async {
            do {
                try handler.perform([request])
            }
            catch {
                print(error)
            }
        }
    }



func handleResult(_ result: [String: Any], currentObservation : VNTextObservation) {
        objc_sync_enter(self)
        guard let wordNumber = result["wordNumber"] as? Int else {
            return
        }
        guard let characterNumber = result["characterNumber"] as? Int else {
            return
        }
        guard let characterClass = result["class"] as? String else {
            return
        }
        if (textMetadata[wordNumber] == nil) {
            let tmp: [Int: String] = [characterNumber: characterClass]
            textMetadata[wordNumber] = tmp
        } else {
            var tmp = textMetadata[wordNumber]!
            tmp[characterNumber] = characterClass
            textMetadata[wordNumber] = tmp
        }
        objc_sync_exit(self)
        DispatchQueue.main.async {
            self.doTextDetection(currentObservation: currentObservation)
        }
    }
    
    func doTextDetection(currentObservation : VNTextObservation) {
        var result: String = ""
        if (textMetadata.isEmpty) {
            print("The image does not contain any text.")
            return
        }
        let sortedKeys = textMetadata.keys.sorted()
        for sortedKey in sortedKeys {
            result +=  word(fromDictionary: textMetadata[sortedKey]!) + " "
            
        }
        
        observationStringLookup[currentObservation] = result
        
    }
    
    func word(fromDictionary dictionary: [Int : String]) -> String {
        let sortedKeys = dictionary.keys.sorted()
        var word: String = ""
        for sortedKey in sortedKeys {
            let char: String = dictionary[sortedKey]!
            word += char
        }
        return word
    }