threshold.java

/*
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 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package task7;

import java.awt.Color;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFileChooser;




/**
 *
 * @author Maestro
 */
public class threshold extends javax.swing.JFrame {

    /**
     * Creates new form threshold
     */
    BufferedImage temp_img;
    public threshold() {
        initComponents();
        
    }

    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">//GEN-BEGIN:initComponents
    private void initComponents() {

        jLabel1 = new javax.swing.JLabel();
        btn_imageChooser = new javax.swing.JButton();
        lbl_image1 = new javax.swing.JLabel();
        lbl_threshold = new javax.swing.JLabel();
        jslice_thresholder = new javax.swing.JSlider();
        txt_slider = new javax.swing.JTextField();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        setPreferredSize(new java.awt.Dimension(750, 560));

        jLabel1.setText("Choose Image");

        btn_imageChooser.setText("Choose");
        btn_imageChooser.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                btn_imageChooserActionPerformed(evt);
            }
        });

        lbl_image1.setPreferredSize(new java.awt.Dimension(350, 350));
        lbl_image1.setSize(new java.awt.Dimension(350, 350));

        lbl_threshold.setPreferredSize(new java.awt.Dimension(350, 350));
        lbl_threshold.setSize(new java.awt.Dimension(350, 350));

        jslice_thresholder.setMaximum(255);
        jslice_thresholder.setPaintLabels(true);
        jslice_thresholder.setPaintTicks(true);
        jslice_thresholder.setToolTipText("");
        jslice_thresholder.setValue(127);
        jslice_thresholder.addChangeListener(new javax.swing.event.ChangeListener() {
            public void stateChanged(javax.swing.event.ChangeEvent evt) {
                jslice_thresholderStateChanged(evt);
            }
        });

        txt_slider.setEditable(false);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jLabel1)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                        .addComponent(btn_imageChooser)
                        .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                            .addGroup(layout.createSequentialGroup()
                                .addGap(433, 433, 433)
                                .addComponent(jslice_thresholder, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                                .addComponent(txt_slider, javax.swing.GroupLayout.PREFERRED_SIZE, 47, javax.swing.GroupLayout.PREFERRED_SIZE))
                            .addGroup(layout.createSequentialGroup()
                                .addComponent(lbl_image1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                                .addComponent(lbl_threshold, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
                        .addGap(419, 419, 419))))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addGroup(layout.createSequentialGroup()
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                            .addComponent(jLabel1)
                            .addComponent(btn_imageChooser))
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(lbl_threshold, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addComponent(lbl_image1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(32, 32, 32)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jslice_thresholder, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(txt_slider, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap(99, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>//GEN-END:initComponents

    private void btn_imageChooserActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_btn_imageChooserActionPerformed
        String userDir = System.getProperty("user.home");
        JFileChooser fileChooser = new JFileChooser(userDir + "/Desktop");

        int result = fileChooser.showOpenDialog(this);
        if (result == JFileChooser.APPROVE_OPTION) {
            File selectedFile = fileChooser.getSelectedFile();
            try {
                final BufferedImage img;
                img = ImageIO.read(selectedFile);
                temp_img=img;
                ImageIcon imgicon= new ImageIcon(img);
                lbl_image1.setIcon(imgicon);
                int threshold=findThreshold(img);
                txt_slider.setText(threshold+"");
                jslice_thresholder.setValue(threshold);
                setThreshold(threshold,img);
            } catch (IOException ex) {
                Logger.getLogger(threshold.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
        
        
        
    }//GEN-LAST:event_btn_imageChooserActionPerformed

    private void jslice_thresholderStateChanged(javax.swing.event.ChangeEvent evt) {//GEN-FIRST:event_jslice_thresholderStateChanged
        // TODO add your handling code here:
        txt_slider.setText(jslice_thresholder.getValue()+"");
        setThreshold(jslice_thresholder.getValue(), temp_img);
    }//GEN-LAST:event_jslice_thresholderStateChanged

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(threshold.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(threshold.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(threshold.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(threshold.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new threshold().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify//GEN-BEGIN:variables
    private javax.swing.JButton btn_imageChooser;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JSlider jslice_thresholder;
    private javax.swing.JLabel lbl_image1;
    private javax.swing.JLabel lbl_threshold;
    private javax.swing.JTextField txt_slider;
    // End of variables declaration//GEN-END:variables

    private void setThreshold(int threshold,BufferedImage img) {
        int width=img.getWidth();
        int height=img.getHeight();
        BufferedImage threshold_img=new BufferedImage(width, height, 6);
        for (int j = 0; j < width; j++) {
            for (int k = 0; k < height; k++) {
                Color c = new Color(img.getRGB(j, k));
                int red=c.getRed();
                int green=c.getGreen();
                int blue=c.getBlue();
                if (red < threshold && green < threshold && blue < threshold) {
                    threshold_img.setRGB(j, k, new Color(0, 0, 0).getRGB());
                } 
                else {
                    threshold_img.setRGB(j, k, new Color(255, 255, 255).getRGB());                
                }
            }          
        }
        lbl_threshold.setIcon(new ImageIcon(threshold_img));
        
    }

    private int findThreshold(BufferedImage img) {
        int threshold;
        int [] histData=new int[256];
        WritableRaster raster = img.getRaster();
        DataBufferByte data = (DataBufferByte)raster.getDataBuffer();
        byte [] srcData=data.getData();
        int ptr = 0;
        while (ptr < srcData.length) {
            int h = 0xFF & srcData[ptr];
            histData[h]++;
            ptr++;
        }
        int total = srcData.length;

        float sum = 0;
        for (int t = 0; t < 256; t++) {
            sum += t * histData[t];
        }

        float sumB = 0;
        int wB = 0;
        int wF = 0;

        float varMax = 0;
        threshold = 0;

        for (int t = 0; t < 256; t++) {
            wB += histData[t];               
            if (wB == 0) {
                continue;
            }

            wF = total - wB;                 
            if (wF == 0) {
                break;
            }

            sumB += (float) (t * histData[t]);

            float mB = sumB / wB;            
            float mF = (sum - sumB) / wF;    
            float varBetween = (float) wB * (float) wF * (mB - mF) * (mB - mF);

            if (varBetween > varMax) {
                varMax = varBetween;
                threshold = t;
            }
        }
        return threshold;
    }
}