iOS身份证号码识别示例

#import <Foundation/Foundation.h>
@class UIImage;

typedef void (^CompleateBlock)(NSString *text);

@interface RecogizeCardManager : NSObject

/**
* 初始化一个单例
*
* @return 返回一个RecogizeCardManager的实例对象
*/
+ (instancetype)recognizeCardManager;

/**
* 根据身份证照片得到身份证号码
*
* @param cardImage 传入的身份证照片
* @param compleate 识别完成后的回调
*/
- (void)recognizeCardWithImage:(UIImage *)cardImage compleate:(CompleateBlock)compleate;

@end

#import "RecogizeCardManager.h"
#import <opencv2/opencv.hpp>
#import <opencv2/imgproc/types_c.h>
#import <opencv2/imgcodecs/ios.h>
#import <TesseractOCR/TesseractOCR.h>

@implementation RecogizeCardManager

+ (instancetype)recognizeCardManager {
  static RecogizeCardManager *recognizeCardManager = nil;
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    recognizeCardManager = [[RecogizeCardManager alloc] init];
  });
  return recognizeCardManager;
}

- (void)recognizeCardWithImage:(UIImage *)cardImage compleate:(CompleateBlock)compleate {
  //扫描身份证图片，并进行预处理，定位号码区域图片并返回
  UIImage *numberImage = [self opencvScanCard:cardImage];
  if (numberImage == nil) {
    compleate(nil);
  }
  //利用TesseractOCR识别文字
  [self tesseractRecognizeImage:numberImage compleate:^(NSString *numbaerText) {
    compleate(numbaerText);
  }];
}

//扫描身份证图片，并进行预处理，定位号码区域图片并返回
- (UIImage *)opencvScanCard:(UIImage *)image {

  //将UIImage转换成Mat
  cv::Mat resultImage;
  UIImageToMat(image, resultImage);
  //转为灰度图
  cvtColor(resultImage, resultImage, cv::COLOR_BGR2GRAY);
  //利用阈值二值化 
  cv::threshold(resultImage, resultImage, 100, 255, CV_THRESH_BINARY);
  //腐蚀，填充（腐蚀是让黑色点变大）
  cv::Mat erodeElement = getStructuringElement(cv::MORPH_RECT, cv::Size(26,26));
  cv::erode(resultImage, resultImage, erodeElement);
  //轮廊检测 
  std::vector<std::vector<cv::Point>> contours;//定义一个容器来存储所有检测到的轮廊
  cv::findContours(resultImage, contours, CV_RETR_TREE, CV_CHAIN_APPROX_SIMPLE, cvPoint(0, 0));
  //取出身份证号码区域
  std::vector<cv::Rect> rects;
  cv::Rect numberRect = cv::Rect(0,0,0,0);
  std::vector<std::vector<cv::Point>>::const_iterator itContours = contours.begin();
  for ( ; itContours != contours.end(); ++itContours) {
    cv::Rect rect = cv::boundingRect(*itContours);
    rects.push_back(rect);
    //算法原理
    if (rect.width > numberRect.width && rect.width > rect.height * 5) {
      numberRect = rect;
    }
  }  
  //身份证号码定位失败
  if (numberRect.width == 0 || numberRect.height == 0) {
    return nil;
  }
  //定位成功成功，去原图截取身份证号码区域，并转换成灰度图、进行二值化处理
  cv::Mat matImage;
  UIImageToMat(image, matImage);
  resultImage = matImage(numberRect);
  cvtColor(resultImage, resultImage, cv::COLOR_BGR2GRAY);
  cv::threshold(resultImage, resultImage, 80, 255, CV_THRESH_BINARY);
  //将Mat转换成UIImage
  UIImage *numberImage = MatToUIImage(resultImage);
  return numberImage;
}

//利用TesseractOCR识别文字
- (void)tesseractRecognizeImage:(UIImage *)image compleate:(CompleateBlock)compleate {

  dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
    G8Tesseract *tesseract = [[G8Tesseract alloc] initWithLanguage:@"eng"];
    tesseract.image = [image g8_blackAndWhite];
    tesseract.image = image;
    // Start the recognition
    [tesseract recognize];
    //执行回调
    compleate(tesseract.recognizedText);
  });
}

#import "RecognizeCardViewController.h"
#import "RecogizeCardManager.h"

@interface RecognizeCardViewController ()<UINavigationControllerDelegate, UIImagePickerControllerDelegate>{
  UIImagePickerController *imgagePickController;
}

@property (weak, nonatomic) IBOutlet UIImageView *imgView;
@property (weak, nonatomic) IBOutlet UILabel *textLabel;
- (IBAction)cameraAction:(id)sender;
- (IBAction)photoAction:(id)sender;

@end

@implementation RecognizeCardViewController

- (void)viewDidLoad {
  [super viewDidLoad];

  self.imgView.contentMode = UIViewContentModeScaleAspectFit;

  imgagePickController = [[UIImagePickerController alloc] init];
  imgagePickController.delegate = self;
  imgagePickController.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
  imgagePickController.allowsEditing = YES;
}

- (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
}

//拍照
- (IBAction)cameraAction:(id)sender {

  //判断是否可以打开照相机
  if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
    imgagePickController.sourceType = UIImagePickerControllerSourceTypeCamera;
    //设置摄像头模式（拍照，录制视频）为拍照
    imgagePickController.cameraCaptureMode = UIImagePickerControllerCameraCaptureModePhoto;
    [self presentViewController:imgagePickController animated:YES completion:nil];
  } else {
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示" message:@"设备不能打开相机" delegate:self cancelButtonTitle:@"知道了" otherButtonTitles: nil];
    [alert show];
  }
}

//相册
- (IBAction)photoAction:(id)sender {
  imgagePickController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
  [self presentViewController:imgagePickController animated:YES completion:nil];
}

#pragma mark - UIImagePickerControllerDelegate
//适用获取所有媒体资源，只需判断资源类型
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info{
  NSString *mediaType=[info objectForKey:UIImagePickerControllerMediaType];
  UIImage *srcImage = nil;
  //判断资源类型
  if ([mediaType isEqualToString:@"public.image"]){
    srcImage = info[UIImagePickerControllerEditedImage];
    self.imgView.image = srcImage;
    //识别身份证
    self.textLabel.text = @"图片插入成功，正在识别中...";
    [[RecogizeCardManager recognizeCardManager] recognizeCardWithImage:srcImage compleate:^(NSString *text) {
      if (text != nil) {
        self.textLabel.text = [NSString stringWithFormat:@"识别结果：%@",text];
      }else {
        self.textLabel.text = @"请选择照片";
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"提示" message:@"照片识别失败，请选择清晰、没有复杂背景的身份证照片重试！" delegate:self cancelButtonTitle:@"知道了" otherButtonTitles: nil];
        [alert show];
      }
    }];
  }
  [self dismissViewControllerAnimated:YES completion:nil];
}

//进入拍摄页面点击取消按钮
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
  [self dismissViewControllerAnimated:YES completion:nil];
}

@end