iOS OCR 之银行卡/身份证信息识别小知识

引言

功能：扫描银行卡识别信息（ 银行名称、 银行卡号）并截取银行卡图像

应用场景：快速填充银行卡号的场景，比如商户进件、实名认证

原理：

1. 自定义相机并利用第三方库SDK​​libexbankcardios.a​​​ 、​​libbexbankcard.a​​​进行识别(识别​​次数无限，免费 ​​)

2.添加自定义的扫描界面（中间有一个镂空窗口和来回移动的扫描线）

I、扫描银行卡

1.1 引入第三方SDK和头文件

exbankcard.h BankCard.h exbankcardcore.h libexbankcardios.a libbexbankcard.a

1.2 获取信息（解码）

#pragma
- (void)parseBankImageBuffer:(CVImageBufferRef)imageBuffer {
    #if

    #else
    size_t width_t= CVPixelBufferGetWidth(imageBuffer);
    size_t height_t = CVPixelBufferGetHeight(imageBuffer);
    CVPlanarPixelBufferInfo_YCbCrBiPlanar *planar = CVPixelBufferGetBaseAddress(imageBuffer);
    size_t offset = NSSwapBigIntToHost(planar->componentInfoY.offset);

    unsigned char* baseAddress = (unsigned char *)CVPixelBufferGetBaseAddress(imageBuffer);
    unsigned char* pixelAddress = baseAddress + offset;

    size_t cbCrOffset = NSSwapBigIntToHost(planar->componentInfoCbCr.offset);
    uint8_t *cbCrBuffer = baseAddress + cbCrOffset;

    CGSize size = CGSizeMake(width_t, height_t);
    CGRect effectRect = [IDCardRectManager getEffectImageRect:size];
    CGRect rect = [IDCardRectManager getGuideFrame:effectRect];

    int width = ceilf(width_t);
    int height = ceilf(height_t);

    unsigned char result [512];
    int resultLen = BankCardNV12(result, 512, pixelAddress, cbCrBuffer, width, height, rect.origin.x, rect.origin.y, rect.origin.x+rect.size.width, rect.origin.y+rect.size.height);

    if(resultLen > 0) {

        int charCount = [IDCardRectManager docode:result len:resultLen];
        if(charCount > 0) {
         //   CGRect subRect = [IDCardRectManager getCorpCardRect:width height:height guideRect:rect charCount:charCount];

            self.isHasResult = YES;
            if ([self.captureSession isRunning]) {
                [self.captureSession stopRunning];
            }
            UIImage *image = [UIImage getImageStream:imageBuffer];
           // __block UIImage *subImg = [UIImage getSubImage:subRect inImage:image];

            char *numbers = [IDCardRectManager getNumbers];

            NSString *numberStr = [NSString stringWithCString:numbers encoding:NSASCIIStringEncoding];
            NSString *bank = [BankCardSearch getBankNameByBin:numbers count:charCount];

             NSLog(@"\n卡号%@\n银行类型%@",numberStr,bank);

            BankCardInfo *model = [JYBDBankCardInfo new];

            model.bankNumber = numberStr;
            model.bankName = bank;
            AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);
            dispatch_async(dispatch_get_main_queue(), ^{

                if (self.finish)
                {
                    self.finish(model, image);
                }
            });
        }
    }
    CVPixelBufferUnlockBaseAddress(imageBuffer, 0);
    self.isInProcessing = NO;
    #endif

1.3 图片裁剪

void)parseBankImageBuffer:(CVImageBufferRef)imageBuffer {
    size_t width_t= CVPixelBufferGetWidth(imageBuffer);
    size_t height_t = CVPixelBufferGetHeight(imageBuffer);
    CGSize size = CGSizeMake(width_t, height_t);

    CGRect effectRect = [IDCardRectManager getEffectImageRect:size];
    CGRect rect = [IDCardRectManager getGuideFrame:effectRect];

            UIImage *image = [UIImage getImageStream:imageBuffer];// image 原图
            __block UIImage *subImg = [UIImage getSubImage:rect inImage:image];// 裁剪 rect

• 工具方法

UIImage *)getImageStream:(CVImageBufferRef)imageBuffer {
    CIImage *ciImage = [CIImage imageWithCVPixelBuffer:imageBuffer];
    CIContext *temporaryContext = [CIContext contextWithOptions:nil];
    CGImageRef videoImage = [temporaryContext createCGImage:ciImage fromRect:CGRectMake(0, 0, CVPixelBufferGetWidth(imageBuffer), CVPixelBufferGetHeight(imageBuffer))];

    UIImage *image = [[UIImage alloc] initWithCGImage:videoImage];

    CGImageRelease(videoImage);
    return image;
}

+ (UIImage *)getSubImage:(CGRect)rect inImage:(UIImage*)image {
    CGImageRef subImageRef = CGImageCreateWithImageInRect(image.CGImage, rect);

    CGRect smallBounds = CGRectMake(0, 0, CGImageGetWidth(subImageRef), CGImageGetHeight(subImageRef));

    UIGraphicsBeginImageContext(smallBounds.size);

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextDrawImage(context, smallBounds, subImageRef);

    UIImage* smallImage = [UIImage imageWithCGImage:subImageRef];
    CFRelease(subImageRef);

    UIGraphicsEndImageContext();

    return

1.4 根据numbers和charCount查询银行名称

II 常见问题

2.1 iOS13适配:present 半屏问题

全屏显示采集界面

- (NSMutableArray *)FullScreenClasss{

    if(_FullScreenClasss == nil){

        [_FullScreenClasss addObject:@"KNAVCapture4IDfrontViewController"];
    }
    return

2.2 Undefined symbols for architecture arm64

Undefined symbols for architecture arm64:
  "_ZIM_SaveImage", referenced from:
      ImgSave(tagIMG, char const*) in libbexbankcard.a(gjimage.o)
  "_ZIM_LoadImage", referenced from:
      ImgLoad(tagIMG&, char const*) in libbexbankcard.a(gjimage.o)
  "_ZIM_DoneImage", referenced from:
      ImgLoad(tagIMG&, char const*) in libbexbankcard.a(gjimage.o)
ld: symbol(s) not found for

解决办法：在TARGETS和PROJECT 两处中build settings 搜索 ENABLE_TESTABILITY 改为NO

RN项目，Dead Code Stripping 设置为yes

see also

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