java图片识别文字的方法

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：

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									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：

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									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 ：

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									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......"); 

									 } 

									}