OCR.java

package com.ocr;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import org.jdesktop.swingx.util.OS;

public class OCR
{


    private final String LANG_OPTION = "-l";


    private final String EOL = System.getProperty("line.separator");


    private String tessPath = new File("tesseract").getAbsolutePath();


    //private String tessPath="C://Program Files (x86)//Tesseract-OCR//";


    public String recognizeText(File imageFile, String imageFormat) throws Exception
    {


        File tempImage = ImageIOHelper.createImage(imageFile, imageFormat);

        File outputFile = new File(imageFile.getParentFile(), "output");

        StringBuffer strB = new StringBuffer();

        List<String> cmd = new ArrayList<String>();

        if (OS.isWindowsXP())
        {
            cmd.add(tessPath + "//tesseract");
        }
        else if (OS.isLinux())
        {
            cmd.add("tesseract");
        }
        else
        {
            cmd.add(tessPath + "//tesseract");
        }

        cmd.add("");
        cmd.add(outputFile.getName());
        cmd.add(LANG_OPTION);
        cmd.add("chi_sim");
        cmd.add("eng");

        ProcessBuilder pb = new ProcessBuilder();

        pb.directory(imageFile.getParentFile());
        cmd.set(1, tempImage.getName());
        pb.command(cmd);
        pb.redirectErrorStream(true);
        Process process = pb.start();

        //tesseract.exe 1.jpg 1 -l chi_sim
        int w = process.waitFor();

        // delete temp working files
        tempImage.delete();

        if (w == 0)
        {
            BufferedReader in = new BufferedReader(new InputStreamReader(new FileInputStream(outputFile.getAbsolutePath() + ".txt"), "UTF-8"));

            String str;
            while ((str = in.readLine()) != null)
            {
                strB.append(str).append(EOL);
            }

            in.close();
        }
        else
        {
            String msg;

            switch (w)
            {
                case 1:
                    msg = "Errors accessing files. There may be spaces in your image's filename.";
                    break;
                case 29:
                    msg = "Cannot recognize the image or its selected region.";
                    break;
                case 31:
                    msg = "Unsupported image format.";
                    break;
                default:
                    msg = "Errors occurred.";
            }

            tempImage.delete();
            throw new RuntimeException(msg);
        }

        new File(outputFile.getAbsolutePath() + ".txt").delete();

        return strB.toString();
    }
}