com.google.zxing.NotFoundException异常是在核心java程序执行时出现的吗？

Question

我有一个带有二维条形码的jpeg文件.图像分辨率为1593X1212.我正在使用xing库从图像中解码这个条形码.我在网上得到了以下代码.

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import javax.imageio.ImageIO;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.ChecksumException;
import com.google.zxing.FormatException;
import com.google.zxing.LuminanceSource;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.NotFoundException;
    import com.google.zxing.Reader;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.HybridBinarizer;


public class NewLibTest {
    public static void main(String args[]){
    System.out.println(decode(new File("E:\\xyz.jpg")));
    }

    /**
      * Decode method used to read image or barcode itself, and recognize the barcode,
      * get the encoded contents and returns it.
     * @param <DecodeHintType>
      * @param file image that need to be read.
      * @param config configuration used when reading the barcode.
      * @return decoded results from barcode.
      */
     public static String decode(File file){//, Map<DecodeHintType, Object> hints) throws Exception {
         // check the required parameters
         if (file == null || file.getName().trim().isEmpty())
             throw new IllegalArgumentException("File not found, or invalid file name.");
         BufferedImage image = null;
         try {
             image = ImageIO.read(file);
         } catch (IOException ioe) {
             try {
                throw new Exception(ioe.getMessage());
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
         }
         if (image == null)
             throw new IllegalArgumentException("Could not decode image.");
         LuminanceSource source = new BufferedImageLuminanceSource(image);
         BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
         MultiFormatReader barcodeReader = new MultiFormatReader();
         Result result;
         String finalResult = null;
         try {
             //if (hints != null && ! hints.isEmpty())
               //  result = barcodeReader.decode(bitmap, hints);
             //else
                 result = barcodeReader.decode(bitmap);
             // setting results.
             finalResult = String.valueOf(result.getText());
         } catch (Exception e) {
             e.printStackTrace();
           //  throw new BarcodeEngine().new BarcodeEngineException(e.getMessage());
         }
         return finalResult;
    }

}

当我执行这个简单的核心java程序时,我给出了异常

com.google.zxing.NotFoundException

它甚至没有给任何stackstrace.

我想问专家,为什么会出现这种异常.谢谢!

Answer 1

我有同样的问题.我使用了一个我知道有一个有效QR码的图像,我也得到了com.google.zxing.NotFoundException.

问题是您用作源的图像对于要解码的库来说很大.在缩小图像尺寸后,QR码解码器工作.

出于我的应用的目的,图像上的QR码总是或多或少在同一区域,因此我使用BufferedImage类的getSubimage函数来隔离QR码.

     BufferedImage image;
     image = ImageIO.read(imageFile);
     BufferedImage cropedImage = image.getSubimage(0, 0, 914, 400);
     // using the cropedImage instead of image
     LuminanceSource source = new BufferedImageLuminanceSource(cropedImage);
     BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
     // barcode decoding
     QRCodeReader reader = new QRCodeReader();
     Result result = null;
     try 
     {
         result = reader.decode(bitmap);
     } 
     catch (ReaderException e) 
     {
         return "reader error";
     }

Answer 2

我有同样的问题.当我在Java SE库上运行几乎完全相同的代码时,它可以工作.当我使用相同的图片运行Android代码时,它无法正常工作.花了很多时间试图找出......

1. 问题:你必须将图片调整为更小.您无法直接使用智能手机图片.它很大.在我的测试中它使用了大约200KB的图片.

您可以使用缩放位图

Bitmap resize = Bitmap.createScaledBitmap(srcBitmap, dstWidth,dstHeight,false);

2. 问题:你必须打开一些标志.几乎所有标志都在玩这个解决方案对我有用:

   Map<DecodeHintType, Object> tmpHintsMap = new EnumMap<DecodeHintType, Object>(
           DecodeHintType.class);
   tmpHintsMap.put(DecodeHintType.TRY_HARDER, Boolean.TRUE);
   tmpHintsMap.put(DecodeHintType.POSSIBLE_FORMATS,
           EnumSet.allOf(BarcodeFormat.class));
   tmpHintsMap.put(DecodeHintType.PURE_BARCODE, Boolean.FALSE);
   

   ...

   MultiFormatReader mfr = null;
   mfr = new MultiFormatReader();
   result = mfr.decode(binaryBitmap, tmpHintsMap);
   

3. 问题:ZXing的Android库运行一次条形码扫描,假设图片上的条形码已经有正确的方向.如果不是这种情况,你必须运行四次,每次旋转图片大约90度!

对于旋转,您可以使用此方法.角度是以度为单位的角度.

    public Bitmap rotateBitmap(Bitmap source, float angle)
    {
          Matrix matrix = new Matrix();
          matrix.postRotate(angle);
          return Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(), matrix, true);
    }

Answer 3

当图像中找不到条形码时会引发该异常：

http://zxing.org/w/docs/javadoc/com/google/zxing/NotFoundException.html