java圖片識別文字的方法

更新時間：2018年09月04日 08:32:40 作者：tiny_lxf

這篇文章主要為大家詳細介紹了java圖片識別文字的方法，具有一定的參考價值，感興趣的小伙伴們可以參考一下

java文字識別程序的關(guān)鍵是尋找一個可以調(diào)用的OCR引擎。tesseract-ocr就是一個這樣的OCR引擎，在1985年到1995年由HP實驗室開發(fā)，現(xiàn)在在Google。tesseract-ocr 3.0發(fā)布，支持中文。不過tesseract-ocr 3.0不是圖形化界面的客戶端，別人寫的FreeOCR圖形化客戶端還不支持導入新的 3.0 traineddata。但這標志著，現(xiàn)在有自由的中文OCR軟件了。

java中使用tesseract-ocr3.01的步驟如下：

1.下載安裝tesseract-ocr-setup-3.01-1.exe（3.0以上版本才增加了中文識別）

2.在安裝向?qū)е锌梢赃x擇需要下載的語言包。

3.到網(wǎng)上搜索下載java圖形處理所需的2個包：jai_imageio-1.1-alpha.jar，swingx-1.6.1.jar

4.java程序清單：

ImageIOHelper 類：

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 類：

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"; //英文字母小寫l，并非數(shù)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+"http://tesseract"); 
  }else if(OS.isLinux()){ 
   cmd.add("tesseract"); 
  }else{ 
   cmd.add(tessPath+"http://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(); 
   
  //刪除臨時正在工作文件 
  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(); 
 } 
}

測試類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......"); 
 } 
 
}

經(jīng)過測試，tesseract-ocr 3.01的文字識別率很高，對于網(wǎng)站中常見的驗證碼識別率也很高。

以上就是本文的全部內(nèi)容，希望對大家的學習有所幫助，也希望大家多多支持腳本之家。

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