使用的第三方庫ZXingObjC(https://github.com/TheLevelUp/ZXingObjC)進行識別，主要程式碼如下：

CGImageRef imageToDecode = image.CGImage; // Given a CGImage in which we are looking for barcodes

ZXLuminanceSource *source = [[ZXCGImageLuminanceSourcealloc] initWithCGImage:imageToDecode];

ZXBinaryBitmap *bitmap = [ZXBinaryBitmapbinaryBitmapWithBinarizer

       NSError *error = nil;

// There are a number of hints we can give to the reader, including

// possible formats, allowed lengths, and the string encoding.

ZXDecodeHints *hints = [ZXDecodeHintshints];

ZXMultiFormatReader *reader = [ZXMultiFormatReaderreader

       ZXResult *result = [reader decode:bitmap

                                   hints:hints

                                   error:&error];

       if (result) {

           NSString *contents = result.text;

           NSLog(@"%@",contents);

        }else {

        }

if

{

    image = ;//使用圖片縮小函式，網上有很多程式碼都可以的

}