NotFoundException 即使图片中有条形码

Question

我正在尝试制作一个简单的条形码扫描仪项目来获得乐趣。我运行遇到了一个小问题。为此，我正在使用 zXing 和 Webcam Capture。

即使图片中有条形码，Java 仍然告诉我 none 是通过 NotFoundException 找到的。每当 webcamImageObtained 为运行（我假设是每一帧？）时，我都会寻找一个帧，然后我在捕获的帧中寻找一个条形码。

我用那个网络摄像头拍了这张照片（具有讽刺意味的是使用代码哈哈）：

当我将鼠标悬停在这个条形码上时，它每秒报告大约 30 张图像，否则当它从我的屏幕上看我时大约每秒 7-8 张（如果这意味着什么）。

每当我找到代码时，我都想将其添加到 JList（尚未考虑重复项等）。

每次 webcamImageObtained(WebcamEvent we) 触发时我都会调用此代码：

@Override
    public void webcamImageObtained(WebcamEvent we) {
        BufferedImage myImage;
        try {
            myImage = webcam.getImage();
            LuminanceSource source = new BufferedImageLuminanceSource(myImage);
            BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
            Result result = reader.decode(bitmap);
            DefaultListModel dlm = (DefaultListModel) list.getModel();
            dlm.addElement(result.toString());
            list.setModel(dlm);
        } catch (NotFoundException ex) {
            Logger.getLogger(AdvancedWebcamPanelExample.class.getName()).log(Level.SEVERE, null, ex);
        } catch (ChecksumException ex) {
            Logger.getLogger(AdvancedWebcamPanelExample.class.getName()).log(Level.SEVERE, null, ex);
        } catch (FormatException ex) {
            Logger.getLogger(AdvancedWebcamPanelExample.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

这里是完整的 class:

package sandbox_webcam;

import com.github.sarxos.webcam.Webcam;
import com.github.sarxos.webcam.WebcamDiscoveryEvent;
import com.github.sarxos.webcam.WebcamDiscoveryListener;
import com.github.sarxos.webcam.WebcamEvent;
import com.github.sarxos.webcam.WebcamListener;
import com.github.sarxos.webcam.WebcamPanel;
import com.github.sarxos.webcam.WebcamPicker;
import com.github.sarxos.webcam.WebcamResolution;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.ChecksumException;
import com.google.zxing.FormatException;
import com.google.zxing.LuminanceSource;
import com.google.zxing.NotFoundException;
import com.google.zxing.Result;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.common.HybridBinarizer;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.lang.Thread.UncaughtExceptionHandler;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;

public class AdvancedWebcamPanelExample extends JFrame implements Runnable, WebcamListener, WindowListener, UncaughtExceptionHandler, ItemListener, WebcamDiscoveryListener {

    private Webcam webcam = null;
    private WebcamPanel panel = null;
    private WebcamPicker picker = null;
    private JButton button = null;
    private JList list = null;
    private ActionListener buttonListener = null;
    private com.google.zxing.Reader reader = new com.google.zxing.MultiFormatReader();

    @Override
    public void run() {
        Webcam.addDiscoveryListener(this);

        setTitle("Java Webcam Capture POC");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new BorderLayout());

        addWindowListener(this);

        picker = new WebcamPicker();
        picker.addItemListener(this);

        webcam = picker.getSelectedWebcam();

        if (webcam == null) {
            System.out.println("No webcams found...");
            System.exit(1);
        }

        webcam.setViewSize(WebcamResolution.VGA.getSize());
        webcam.addWebcamListener(AdvancedWebcamPanelExample.this);

        panel = new WebcamPanel(webcam, false);
        panel.setFPSDisplayed(true);

        buttonListener = new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                if (webcam != null) {
                    BufferedImage image = webcam.getImage();
                    JFileChooser filechooser = new JFileChooser();

                    int saveValue = filechooser.showDialog(button, "Save");
                    if (saveValue == JFileChooser.APPROVE_OPTION) {
                        try {
                            File f = filechooser.getSelectedFile();
                            ImageIO.write(image, "png", new File(f.getAbsolutePath() + ".png"));
                            System.out.println("Picture saved at: " + f.getAbsolutePath());
                        } catch (IOException ex) {
                            System.err.println("Failed to save the picture!");
                            ex.printStackTrace();
                        }
                    }
                } else {
                    System.err.println("no webcam found to take a picture");
                }
            }
        };

        button = new JButton("Snap a Picture!");
        button.addActionListener(buttonListener);
        list = new JList();
        list.setMinimumSize(new Dimension(200,this.getHeight()));

        add(picker, BorderLayout.NORTH);
        add(panel, BorderLayout.CENTER);
        add(button, BorderLayout.SOUTH);
        add(list, BorderLayout.EAST);

        pack();
        setVisible(true);

        Thread t = new Thread() {
            @Override
            public void run() {
                panel.start();
            }
        };

        t.setName("example-starter");
        t.setDaemon(true);
        t.setUncaughtExceptionHandler(this);
        t.start();
    }

    @Override
    public void webcamOpen(WebcamEvent we) {
        System.out.println("webcam open");
    }

    @Override
    public void webcamClosed(WebcamEvent we) {
        System.out.println("webcam closed");
    }

    @Override
    public void webcamDisposed(WebcamEvent we) {
        System.out.println("webcam disposed");
    }

    @Override
    public void webcamImageObtained(WebcamEvent we) {
        BufferedImage myImage;
        try {
            myImage = webcam.getImage();
            LuminanceSource source = new BufferedImageLuminanceSource(myImage);
            BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
            Result result = reader.decode(bitmap);
            DefaultListModel dlm = (DefaultListModel) list.getModel();
            dlm.addElement(result.toString());
            list.setModel(dlm);
        } catch (NotFoundException ex) {
            Logger.getLogger(AdvancedWebcamPanelExample.class.getName()).log(Level.SEVERE, null, ex);
        } catch (ChecksumException ex) {
            Logger.getLogger(AdvancedWebcamPanelExample.class.getName()).log(Level.SEVERE, null, ex);
        } catch (FormatException ex) {
            Logger.getLogger(AdvancedWebcamPanelExample.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    @Override
    public void windowOpened(WindowEvent e) {
        // do nothing
    }

    @Override
    public void windowClosing(WindowEvent e) {
        // do nothing
    }

    @Override
    public void windowClosed(WindowEvent e) {
        webcam.close();
    }

    @Override
    public void windowIconified(WindowEvent e) {
        System.out.println("webcam viewer paused");
        panel.pause();
    }

    @Override
    public void windowDeiconified(WindowEvent e) {
        System.out.println("webcam viewer resumed");
        panel.resume();
    }

    @Override
    public void windowActivated(WindowEvent e) {
        // do nothing
    }

    @Override
    public void windowDeactivated(WindowEvent e) {
        // do nothing
    }

    @Override
    public void uncaughtException(Thread t, Throwable e) {
        System.err.println(String.format("Exception in thread #s", t.getName()));
        e.printStackTrace();
    }

    @Override
    public void itemStateChanged(ItemEvent e) {
        if (e.getItem() != webcam) {
            if (webcam != null) {
                panel.stop();

                remove(panel);
                webcam.removeWebcamListener(this);
                webcam.close();

                webcam = (Webcam) e.getItem();
                webcam.setViewSize(WebcamResolution.VGA.getSize());
                webcam.addWebcamListener(this);

                System.out.println("selected " + webcam.getName());

                panel = new WebcamPanel(webcam, false);
                panel.setFPSDisplayed(true);

                add(panel, BorderLayout.CENTER);
                pack();

                Thread t = new Thread() {
                    @Override
                    public void run() {
                        panel.start();
                    }
                };

                t.setName("example-stopper");
                t.setDaemon(true);
                t.setUncaughtExceptionHandler(this);
                t.start();
            }
        }
    }

    @Override
    public void webcamFound(WebcamDiscoveryEvent event) {
        if (picker != null) {
            picker.addItem(event.getWebcam());
        }
    }

    @Override
    public void webcamGone(WebcamDiscoveryEvent event) {
        if (picker != null) {
            picker.removeItem(event.getWebcam());
        }
    }

}

我是否遗漏了有关此库如何扫描条形码的信息？

编辑

不确定这有多大帮助..

Mar 02, 2015 10:04:34 PM sandbox_webcam.AdvancedWebcamPanelExample webcamImageObtained
SEVERE: null
com.google.zxing.NotFoundException

此处抛出异常：

Result result = reader.decode(bitmap);

Answer 1

有一个不同的问题有一些可用的答案：Android zxing NotFoundException

正如 James 所说，在不同的介质 (paper/screen) 上尝试使用条码是个好主意，如果它不起作用，并且在不同的环境和照明条件下。尤其要保证光线充足，并且相机对着条码时的FPS足够高。

为了调试，还可以将 BinaryImage 转换回可见格式，并检查转换为黑白后条码是否真正可见。

NotFoundException 即使图片中有条形码

NotFoundException even when a barcode is in the picture

java

swing

webcam

zxing