识别率很高的java文字识别技术

java文字识别程序的关键是寻找一个可以调用的OCR引擎。tesseract-ocr就是一个这样的OCR引擎，在1985年到1995年由HP实验室开发，现在在Google。tesseract-ocr 3.0发布，支持中文。不过tesseract-ocr 3.0不是图形化界面的客户端，别人写的FreeOCR图形化客户端还不支持导入新的 3.0 traineddata。但这标志着，现在有自由的中文OCR软件了。

java中使用tesseract-ocr3.01的步骤如下：

1.下载安装tesseract-ocr-setup-3.01-1.exe（3.0以上版本才增加了中文识别）

2.在安装向导中可以选择需要下载的语言包。

3.到网上搜索下载java图形处理所需的2个包：jai_imageio-1.1-alpha.jar，swingx-1.6.1.jar

4.java程序清单：

ImageIOHelper 类：

import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import java.util.Iterator;import java.util.Locale;import javax.imageio.IIOImage;import javax.imageio.ImageIO;import javax.imageio.ImageReader;import javax.imageio.ImageWriteParam;import javax.imageio.ImageWriter;import javax.imageio.metadata.IIOMetadata;import javax.imageio.stream.ImageInputStream;import javax.imageio.stream.ImageOutputStream;import com.sun.media.imageio.plugins.tiff.TIFFImageWriteParam;public class ImageIOHelper {    public static File createImage(File imageFile, String imageFormat) {   File tempFile = null;   try {    Iterator readers = ImageIO.getImageReadersByFormatName(imageFormat);    ImageReader reader = readers.next();       ImageInputStream iis = ImageIO.createImageInputStream(imageFile);    reader.setInput(iis);    //Read the stream metadata    IIOMetadata streamMetadata = reader.getStreamMetadata();        //Set up the writeParam    TIFFImageWriteParam tiffWriteParam = new TIFFImageWriteParam(Locale.CHINESE);    tiffWriteParam.setCompressionMode(ImageWriteParam.MODE_DISABLED);        //Get tif writer and set output to file    Iterator writers = ImageIO.getImageWritersByFormatName("tiff");    ImageWriter writer = writers.next();        BufferedImage bi = reader.read(0);    IIOImage image = new IIOImage(bi,null,reader.getImageMetadata(0));    tempFile = tempImageFile(imageFile);    ImageOutputStream ios = ImageIO.createImageOutputStream(tempFile);    writer.setOutput(ios);    writer.write(streamMetadata, image, tiffWriteParam);    ios.close();        writer.dispose();    reader.dispose();       } catch (IOException e) {    e.printStackTrace();   }   return tempFile;  }   private static File tempImageFile(File imageFile) {   String path = imageFile.getPath();   StringBuffer strB = new StringBuffer(path);   strB.insert(path.lastIndexOf('.'),0);   return new File(strB.toString().replaceFirst("(?<=//.)(//w+)$", "tif"));  }  } 

OCR 类：

package com.hhp.util;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"; //英文字母小写l，并非数字1  private final String EOL = System.getProperty("line.separator");  private String tessPath = "C://Program Files (x86)//Tesseract-OCR";  //private String tessPath = new File("tesseract").getAbsolutePath();    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 cmd = new ArrayList();   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();      //删除临时正在工作文件   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 recongnize 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();  } }

测试类TestOCR ：

import java.io.File;import java.io.IOException;import com.hhp.util.OCR;public class OcrTest { public static void main(String[] args) {  String path = "C://temp//OCRcode//4.png";    System.out.println("ORC Test Begin......");  try {     String valCode = new OCR().recognizeText(new File(path), "png");     System.out.println(valCode);    } catch (IOException e) {     e.printStackTrace();    } catch (Exception e) {    e.printStackTrace();   }    System.out.println("ORC Test End......"); } }

经过测试，tesseract-ocr 3.01的文字识别率很高，对于网站中常见的验证码识别率也很高。

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