扫描的条形码很少，但很少使用Zxing

Question

I am using zxing to scan barcode and split that in pdf. But most barcodes are scanned and few aren't. Although all barcodes are properly visible and i can scan them using barcode android app. my code is

    Boolean flag = Boolean.FALSE;
    PDDocument pdfDoc = null;
    Result prevResult = null;
    try{
        pdfDoc = PDDocument.load(new File(pathToReadPdf));
        log.debug("Total pdf pages : "+pdfDoc.getNumberOfPages());

        Reader reader = new MultiFormatReader();
        List<PDPage> pages = pdfDoc.getDocumentCatalog().getAllPages();
        for(PDPage page : pages) {
            PDResources resources = page.getResources();
            // Identify images from pdf
            Map images = resources.getImages();
            if( images != null ){
                Iterator imageIter = images.keySet().iterator();
                while( imageIter.hasNext()){
                    String key = (String)imageIter.next();
                    PDXObjectImage image = (PDXObjectImage)images.get( key );
                    if (image.getRGBImage()!=null){
                    Hashtable<DecodeHintType, Object> decodeHints = new Hashtable<DecodeHintType, Object>(3);
                    Vector<BarcodeFormat> barcodeFormats = new Vector<BarcodeFormat>();
                    barcodeFormats.add(BarcodeFormat.CODE_128);
                    decodeHints.put(DecodeHintType.POSSIBLE_FORMATS, barcodeFormats);
                    decodeHints.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
                    decodeHints.put(DecodeHintType.PURE_BARCODE, true);
                    //decodeHints.put(DecodeHintType.CHARACTER_SET, "ISO-8859-1");
                    LuminanceSource source = new BufferedImageLuminanceSource(image.getRGBImage(), 0, 0, image.getWidth(), image.getHeight());
                    BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
                    Result result = null;

                    try{
                        result = reader.decode(bitmap, decodeHints);
                        splitPdf(page, result, loanApplicationId);
                        prevResult= result;
                        flag = Boolean.TRUE;
                    }catch(NotFoundException nfe){
                        if(prevResult!=null){
                            mergePDF(page, prevResult, loanApplicationId);
                        }
                        continue;
                    }
                    log.debug("Barcode text is " + result.getText());
                    }
                }
            }
        }
    }catch(Exception e){
        e.printStackTrace();
        log.error("Error while splitting PDF : " + e.getMessage(), e);
    }
    finally {
        try{
            if(pdfDoc != null){
                pdfDoc.close();
            }
        }catch (IOException ioe){
            ioe.printStackTrace();
            log.error("Error while closing PDF : " + ioe.getMessage(), ioe);
        }
    }
    return flag;` 

I think error might be in bitmap conversion. I am getting error at com.google.zxing.NotFoundException at result = reader.decode(bitmap, decodeHints);

barcode creation logic:

 public byte[] createBarCode128(String fileName) {

    byte[] imageInByte = new byte[1024];
    try {
        Code128Bean bean = new Code128Bean();
        final int dpi = 300;

        //Configure the barcode generator
        bean.setModuleWidth(UnitConv.in2mm(6.0f / dpi));
        bean.doQuietZone(false);

        BitmapCanvasProvider canvas = new BitmapCanvasProvider(null, "image/x-png", dpi, BufferedImage.TYPE_BYTE_BINARY, false, 0);

        //Generate the barcode
        bean.generateBarcode(canvas, fileName);

        //Signal end of generation
        canvas.finish();

        BufferedImage originalImage = canvas.getBufferedImage();
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ImageIO.write(originalImage, "jpg", baos);
        baos.flush();
        imageInByte = baos.toByteArray();
        log.debug(imageInByte.toString());
        baos.close();
        log.debug(" Bar Code is generated successfully ");
    }
    catch (IOException ex) {
        ex.printStackTrace();
        log.error(ex.getMessage(),ex);
    }
    return imageInByte;
}

I am using below dependencies:

 <dependency>
        <groupId>com.google.zxing</groupId>
        <artifactId>core</artifactId>
        <version>2.3.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.pdfbox</groupId>
        <artifactId>fontbox</artifactId>
        <version>1.8.0</version>
    </dependency>
    <dependency>
        <groupId>org.apache.pdfbox</groupId>
        <artifactId>pdfbox</artifactId>
        <version>1.8.0</version>
    </dependency>
    <dependency>
        <groupId>com.google.zxing</groupId>
        <artifactId>javase</artifactId>
        <version>2.2</version>
    </dependency>

my java version is 6 so zxing version 3 is not supported.

Please suggest any solution.

Answer 1

Having looked at the sample file provided by the OP I can see no real differences between the barcodes zxing can scan and those it cannot scan. They all seem to be scanned at 300 dpi and embedded in the same fashion.

Zooming into the image one can see, though, that the scanning quality is quite poor for the purpose of barcode recognition:

The scanned bar code outlines are not sharply cut and have some saw tooth pattern. This makes the bars appear to be of differing width on differing scan lines.

I assume you simply are lucky with the codes you can recognize.

I'd propose changing the scan properties, maybe b&w instead of grayscale, maybe a different resolution...

Answer 2

As you said, some barcode are scanning and some are not. Please check whether that format is in Zxing list supported format.

1. QR_CODE
2. DATA_MATRIX
3. UPC_E
4. UPC_A
5. EAN_8
6. EAN_13
7. UPC_EAN_EXTENSION
8. CODE_128
9. CODE_39

You can give the code and test in this. http://www.barcode-generator.org/