Gelişmiş Metin Algılama Teknikleri (Vision + TesserAct OCR) | iOS --- http://www.bulentsiyah.com/gelismis-metin-algilama-teknikleri-vision-tesseract-ocr-ios/

IleriMetinTanimaViewController.swift

//
//  IleriMetinTanimaViewController.swift
//  ML Ornekleri
//
//  Created by Bülent Siyah on 5.07.2018.
//  Copyright © 2018 Bülent Siyah. All rights reserved.
//

import UIKit
import Vision
import TesseractOCR

class IleriMetinTanimaViewController: UIViewController , UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    
    @IBOutlet weak var imageView: UIImageView!
  
    @IBOutlet weak var txtResult: UITextView!
    var imagePicker: UIImagePickerController!
    var userPickedImage: UIImage?
    
    override func viewDidLoad() {
        super.viewDidLoad()

        imagePicker = UIImagePickerController()
        imagePicker.delegate = self

    }

    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        
        if let pickedImage = info[UIImagePickerControllerOriginalImage] as? UIImage {
            imageView.contentMode = .scaleAspectFit
            imageView.image = pickedImage
            self.userPickedImage = pickedImage
        }
        
        dismiss(animated: true, completion: nil)
    }
    
    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        dismiss(animated: true, completion: nil)
    }
    
    @IBAction func btnResimCek(_ sender: Any) {
        imagePicker.allowsEditing = false
        imagePicker.sourceType = .photoLibrary
        present(imagePicker, animated: true, completion: nil)
    }
    
    @IBAction func btnAnalizEt(_ sender: Any) {
        
        findText()
        recognizeTextImage()
    }
    
    func findText() {
        
        // VN Request Rectangles (faces / Text)
        
        var textLayers: [CAShapeLayer] = []
        let textDetectionRequest = VNDetectTextRectanglesRequest(completionHandler: { (request, error) in
            
            guard let observations = request.results as? [VNTextObservation] else {
                fatalError("unexpected results")
            }
            
            //self.addShapesToText
            textLayers = self.addShapesToText(forObservations: observations, withImageView: self.imageView)
            
        })
        
        if let image = self.imageView.image, let cgImage = image.cgImage {
            
            let handler = VNImageRequestHandler(cgImage: cgImage, options: [:])
            
            guard let _ = try? handler.perform([textDetectionRequest]) else {
                return print("could not perform the text detection request")
            }
            
            for layer in textLayers {
                self.imageView.layer.addSublayer(layer)
            }
            
        }
        
    }
    
    func addShapesToText(forObservations observations: [VNTextObservation], withImageView textImageView: UIImageView) -> [CAShapeLayer] {
        
        let layers: [CAShapeLayer] = observations.map {observation in
            
            let w = observation.boundingBox.size.width * textImageView.bounds.width
            let h = observation.boundingBox.size.height * textImageView.bounds.height
            let x = observation.boundingBox.origin.x * textImageView.bounds.width
            let y = abs(((observation.boundingBox.origin.y * (textImageView.bounds.height)) - textImageView.bounds.height )) - h
            
            let layer = CAShapeLayer()
            layer.frame = CGRect(x: x, y: y, width: w, height: h)
            layer.borderColor = UIColor.red.cgColor
            layer.cornerRadius = 5
            layer.borderWidth = 5
            layer.strokeColor = UIColor.red.cgColor
            layer.backgroundColor = UIColor.green.cgColor
            layer.opacity =  0.5 // 0 - 1
            
            return layer
            
        }
        
        return layers
        
    }
    
    func recognizeTextImage(){
        if let tesseract = G8Tesseract(language: "eng+fra"){
            tesseract.engineMode = .tesseractCubeCombined
            tesseract.pageSegmentationMode = .auto
            tesseract.image = userPickedImage?.g8_blackAndWhite()
            tesseract.recognize()
            txtResult.text = tesseract.recognizedText
            
        }
        
    }
}