ZXing格式异常

Question

我正在使用Java zxing库使用网络摄像头扫描阿兹台克代码。不幸的是，每次尝试扫描我的Aztec时，我都会收到FormatException。看起来它检测到代码，然后出了点问题-抛出NotFoundException，直到我将Aztec放在网络摄像头前。代码：

    public static String readQRCode(BufferedImage image) {
    BinaryBitmap bitmap = null;
    Result result = null;

    int[] pixels = image.getRGB(0, 0, image.getWidth(), image.getHeight(), null, 0, image.getWidth());
    RGBLuminanceSource source = new RGBLuminanceSource(image.getWidth(), image.getHeight(), pixels);
    bitmap = new BinaryBitmap(new HybridBinarizer(source));            
    Map<DecodeHintType,Object> tmpHintsMap = new EnumMap<DecodeHintType, Object>(DecodeHintType.class);
    tmpHintsMap.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
    tmpHintsMap.put(DecodeHintType.PURE_BARCODE, Boolean.FALSE);
    tmpHintsMap.put(DecodeHintType.POSSIBLE_FORMATS, BarcodeFormat.AZTEC);

    if (bitmap == null)
        return null;

    QRCodeReader reader = new QRCodeReader();  
    try {
        result = reader.decode(bitmap, tmpHintsMap);
        return result.getText();
    } catch (NotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (ChecksumException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (FormatException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    return null;
}

我尝试了不同的阿兹台克人，结果总是一样。图片尺寸为640x480。你们有什么主意吗？预先感谢。