本文介绍了一个用Java实现的简单图像文本二值处理方法。通过构建字符模板矩阵，并将待识别字符转换为二值矩阵，实现了初步的文字匹配。文章提供了源代码示例。
摘要
图像识别是目前很热门的研究领域，涉及的知识很广，包括信息论、模式识别、模糊数学、图像编码、内容分类等等。本文仅对使用Java实现了一个简单的图像文本二值处理，关于识别并未实现。步骤
-
建立文本字符模板二值矩阵
-
对测试字符进行二值矩阵化处理
代码
/*
*@(#)StdModelRepository.java
*
*Thisprogramisfreesoftware;youcanredistributeitand/ormodify
*itunderthetermsoftheGNUGeneralPublicLicenseaspublishedby
*theFreeSoftwareFoundation;eitherversion3oftheLicense,or
*(atyouroption)anylaterversion.
*
*Thisprogramisdistributedinthehopethatitwillbeuseful,
*butWITHOUTANYWARRANTY;withouteventheimpliedwarrantyof
*MERCHANTABILITYorFITNESSFORAPARTICULARPURPOSE.Seethe
*GNULibraryGeneralPublicLicenseformoredetails.
*YoushouldhavereceivedacopyoftheGNUGeneralPublicLicense
*alongwiththisprogram;ifnot,writetotheFreeSoftware
*Foundation,Inc.,59TemplePlace-Suite330,Boston,MA02111-1307,USA.
*/
package cn.edu.ynu.sei.recognition.util;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
/**
*HoldcharactercharImgsasstandardmodelrepository.
* @author 88250
* @version 1.0.0.0,Mar20,2008
*/
public class StdModelRepository{
/**
*holdcharacterimages
*/
List < BufferedImage > charImgs = new ArrayList < BufferedImage > ();
/**
*defaultwidthofacharacter
*/
static int width = 16 ;
/**
*defaultheightofacharacter
*/
static int height = 28 ;
/**
*standardcharactermodelmatrix
*/
public int [][][]stdCharMatrix = new int [ 27 ][width][height];
/**
*Defaultconstructor.
*/
public StdModelRepository(){
BufferedImagelowercase = null ;
try {
lowercase = ImageIO.read( new File( " lowercase.png " ));
} catch (IOExceptionex){
Logger.getLogger(StdModelRepository. class .getName()).
log(Level.SEVERE, null ,ex);
}
for ( int i = 0 ;i < 26 ;i ++ ){
charImgs.add(lowercase.getSubimage(i * width,
0 ,
width,
height));
}
for ( int i = 0 ;i < charImgs.size();i ++ ){
Imageimage = charImgs.get(i);
int []pixels = ImageUtils.getPixels(image,
image.getWidth( null ),
image.getHeight( null ));
stdCharMatrix[i] = ImageUtils.getSymbolMatrix(pixels, 0 ).clone();
ImageUtils.displayMatrix(stdCharMatrix[i]);
}
}
}
*@(#)StdModelRepository.java
*
*Thisprogramisfreesoftware;youcanredistributeitand/ormodify
*itunderthetermsoftheGNUGeneralPublicLicenseaspublishedby
*theFreeSoftwareFoundation;eitherversion3oftheLicense,or
*(atyouroption)anylaterversion.
*
*Thisprogramisdistributedinthehopethatitwillbeuseful,
*butWITHOUTANYWARRANTY;withouteventheimpliedwarrantyof
*MERCHANTABILITYorFITNESSFORAPARTICULARPURPOSE.Seethe
*GNULibraryGeneralPublicLicenseformoredetails.
*YoushouldhavereceivedacopyoftheGNUGeneralPublicLicense
*alongwiththisprogram;ifnot,writetotheFreeSoftware
*Foundation,Inc.,59TemplePlace-Suite330,Boston,MA02111-1307,USA.
*/
package cn.edu.ynu.sei.recognition.util;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
/**
*HoldcharactercharImgsasstandardmodelrepository.
* @author 88250
* @version 1.0.0.0,Mar20,2008
*/
public class StdModelRepository{
/**
*holdcharacterimages
*/
List < BufferedImage > charImgs = new ArrayList < BufferedImage > ();
/**
*defaultwidthofacharacter
*/
static int width = 16 ;
/**
*defaultheightofacharacter
*/
static int height = 28 ;
/**
*standardcharactermodelmatrix
*/
public int [][][]stdCharMatrix = new int [ 27 ][width][height];
/**
*Defaultconstructor.
*/
public StdModelRepository(){
BufferedImagelowercase = null ;
try {
lowercase = ImageIO.read( new File( " lowercase.png " ));
} catch (IOExceptionex){
Logger.getLogger(StdModelRepository. class .getName()).
log(Level.SEVERE, null ,ex);
}
for ( int i = 0 ;i < 26 ;i ++ ){
charImgs.add(lowercase.getSubimage(i * width,
0 ,
width,
height));
}
for ( int i = 0 ;i < charImgs.size();i ++ ){
Imageimage = charImgs.get(i);
int []pixels = ImageUtils.getPixels(image,
image.getWidth( null ),
image.getHeight( null ));
stdCharMatrix[i] = ImageUtils.getSymbolMatrix(pixels, 0 ).clone();
ImageUtils.displayMatrix(stdCharMatrix[i]);
}
}
}
/*
*@(#)ImageUtils.java
*
*Thisprogramisfreesoftware;youcanredistributeitand/ormodify
*itunderthetermsoftheGNUGeneralPublicLicenseaspublishedby
*theFreeSoftwareFoundation;eitherversion3oftheLicense,or
*(atyouroption)anylaterversion.
*
*Thisprogramisdistributedinthehopethatitwillbeuseful,
*butWITHOUTANYWARRANTY;withouteventheimpliedwarrantyof
*MERCHANTABILITYorFITNESSFORAPARTICULARPURPOSE.Seethe
*GNULibraryGeneralPublicLicenseformoredetails.
*YoushouldhavereceivedacopyoftheGNUGeneralPublicLicense
*alongwiththisprogram;ifnot,writetotheFreeSoftware
*Foundation,Inc.,59TemplePlace-Suite330,Boston,MA02111-1307,USA.
*/
package cn.edu.ynu.sei.recognition.util;
import java.awt.Image;
import java.awt.image.PixelGrabber;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
*Mainipulationofimagedata.
* @author 88250
* @version 1.0.0.3,Mar20,2008
*/
public class ImageUtils{
/**
*Returnallofthepixelvaluesofsepecified<code>image</code>.
* @param imagethesepecifiedimage
* @param widthwidthofthe<code>image</code>
* @param heightheightofthe<code>image</code>
* @return
*/
public static int []getPixels(Imageimage, int width, int height){
int []pixels = new int [width * height];
try {
new PixelGrabber(image, 0 , 0 ,width,height,pixels, 0 ,width).grabPixels();
} catch (InterruptedExceptionex){
Logger.getLogger(ImageUtils. class .getName()).
log(Level.SEVERE, null ,ex);
}
return pixels;
}
/**
*Getamatrixthatdescribedthe<code>pixels</code>.
*<p>
*Forexample,theresultofthematrixlikethis:
*<center>
*0000000000000000<br>
*0000000000000000<br>
*0001111111110000<br>
*0011111111111000<br>
*0011111111111100<br>
*0011000000011100<br>
*0000000000011100<br>
*0000111111111100<br>
*0011111111111100<br>
*0011111110011100<br>
*0111100000011100<br>
*0111100000011100<br>
*0111100000111100<br>
*0111100001111110<br>
*0011111111111100<br>
*0011111111111100<br>
*0001111111111100<br>
*0000000000000000<br>
*0000000000000000<br>
*</center>
*itdescribesthealphbet'a'.
*</p>
* @param pixelsthepixelarray
* @param sparseFactorsparsefactor
* @return amatrixthatdescribesaalphbet
*/
public static int [][]getSymbolMatrix( int []pixels, int sparseFactor){
final int width = StdModelRepository.width;
final int height = StdModelRepository.height;
int [][]ret = new int [width][height];
for ( int i = 0 ;i < height;i ++ ){
for ( int j = 0 ;j < width;j ++ ){
if (pixels[i * width + j] == - 1 ){
ret[j][i] = 0 ;
} else {
ret[j][i] = 1 ;
}
}
}
return ret;
}
/**
*Printthe<code>matrix</code>underconsole.
* @param matrixthesepecifiedmatrixdata
*/
public static void displayMatrix( int [][]matrix){
System.out.println( " " );
for ( int i = 0 ;i < matrix[ 0 ].length;i ++ ){
for ( int j = 0 ;j < matrix.length;j ++ ){
if (matrix[j][i] != 0 ){
System.out.print( " * " );
} else {
System.out.print( " " );
}
}
System.out.println();
}
}
}
*@(#)ImageUtils.java
*
*Thisprogramisfreesoftware;youcanredistributeitand/ormodify
*itunderthetermsoftheGNUGeneralPublicLicenseaspublishedby
*theFreeSoftwareFoundation;eitherversion3oftheLicense,or
*(atyouroption)anylaterversion.
*
*Thisprogramisdistributedinthehopethatitwillbeuseful,
*butWITHOUTANYWARRANTY;withouteventheimpliedwarrantyof
*MERCHANTABILITYorFITNESSFORAPARTICULARPURPOSE.Seethe
*GNULibraryGeneralPublicLicenseformoredetails.
*YoushouldhavereceivedacopyoftheGNUGeneralPublicLicense
*alongwiththisprogram;ifnot,writetotheFreeSoftware
*Foundation,Inc.,59TemplePlace-Suite330,Boston,MA02111-1307,USA.
*/
package cn.edu.ynu.sei.recognition.util;
import java.awt.Image;
import java.awt.image.PixelGrabber;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
*Mainipulationofimagedata.
* @author 88250
* @version 1.0.0.3,Mar20,2008
*/
public class ImageUtils{
/**
*Returnallofthepixelvaluesofsepecified<code>image</code>.
* @param imagethesepecifiedimage
* @param widthwidthofthe<code>image</code>
* @param heightheightofthe<code>image</code>
* @return
*/
public static int []getPixels(Imageimage, int width, int height){
int []pixels = new int [width * height];
try {
new PixelGrabber(image, 0 , 0 ,width,height,pixels, 0 ,width).grabPixels();
} catch (InterruptedExceptionex){
Logger.getLogger(ImageUtils. class .getName()).
log(Level.SEVERE, null ,ex);
}
return pixels;
}
/**
*Getamatrixthatdescribedthe<code>pixels</code>.
*<p>
*Forexample,theresultofthematrixlikethis:
*<center>
*0000000000000000<br>
*0000000000000000<br>
*0001111111110000<br>
*0011111111111000<br>
*0011111111111100<br>
*0011000000011100<br>
*0000000000011100<br>
*0000111111111100<br>
*0011111111111100<br>
*0011111110011100<br>
*0111100000011100<br>
*0111100000011100<br>
*0111100000111100<br>
*0111100001111110<br>
*0011111111111100<br>
*0011111111111100<br>
*0001111111111100<br>
*0000000000000000<br>
*0000000000000000<br>
*</center>
*itdescribesthealphbet'a'.
*</p>
* @param pixelsthepixelarray
* @param sparseFactorsparsefactor
* @return amatrixthatdescribesaalphbet
*/
public static int [][]getSymbolMatrix( int []pixels, int sparseFactor){
final int width = StdModelRepository.width;
final int height = StdModelRepository.height;
int [][]ret = new int [width][height];
for ( int i = 0 ;i < height;i ++ ){
for ( int j = 0 ;j < width;j ++ ){
if (pixels[i * width + j] == - 1 ){
ret[j][i] = 0 ;
} else {
ret[j][i] = 1 ;
}
}
}
return ret;
}
/**
*Printthe<code>matrix</code>underconsole.
* @param matrixthesepecifiedmatrixdata
*/
public static void displayMatrix( int [][]matrix){
System.out.println( " " );
for ( int i = 0 ;i < matrix[ 0 ].length;i ++ ){
for ( int j = 0 ;j < matrix.length;j ++ ){
if (matrix[j][i] != 0 ){
System.out.print( " * " );
} else {
System.out.print( " " );
}
}
System.out.println();
}
}
}
/*
*@(#)ImageTextRecognitor.java
*
*Thisprogramisfreesoftware;youcanredistributeitand/ormodify
*itunderthetermsoftheGNUGeneralPublicLicenseaspublishedby
*theFreeSoftwareFoundation;eitherversion3oftheLicense,or
*(atyouroption)anylaterversion.
*
*Thisprogramisdistributedinthehopethatitwillbeuseful,
*butWITHOUTANYWARRANTY;withouteventheimpliedwarrantyof
*MERCHANTABILITYorFITNESSFORAPARTICULARPURPOSE.Seethe
*GNULibraryGeneralPublicLicenseformoredetails.
*YoushouldhavereceivedacopyoftheGNUGeneralPublicLicense
*alongwiththisprogram;ifnot,writetotheFreeSoftware
*Foundation,Inc.,59TemplePlace-Suite330,Boston,MA02111-1307,USA.
*/
package cn.edu.ynu.sei.recognition;
import cn.edu.ynu.sei.recognition.util.StdModelRepository;
import cn.edu.ynu.sei.recognition.util.ImageUtils;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
/**
*Demonstraterecognitioncharactersfromaimage.
* @author 88250
* @version 1.0.0.2,Mar20,2008
*/
public class ImageTextRecognitor{
private final static long serialVersionUID = 1L ;
private StdModelRepositorysmr = new StdModelRepository();
private BufferedImagebufferedImage;
/**
*Defaultconstructor.
*/
public ImageTextRecognitor(){
try {
bufferedImage = ImageIO.read( new File( " a_yahei12.png " ));
} catch (IOExceptionex){
Logger.getLogger(StdModelRepository. class .getName()).
log(Level.SEVERE, null ,ex);
}
}
/**
*Returnthematchedcharacterwithsepecifiedimage.
* @param symbolMatrixthematrixofsepecifiedimage
* @return thecharacter
*/
// TODO:thecorealgorithm
public char getMatchResult( int [][]symbolMatrix){
char result = 0 ;
int tmpEvaluation = 100 ;
int evaluation = 0 ;
return result;
}
/**
*Mainprogramentry.
* @param argsshouldbe<code>null</code>
*/
public static void main(String[]args){
ImageTextRecognitorirt = new ImageTextRecognitor();
BufferedImagebi = irt.bufferedImage;
Imageimg = bi.getScaledInstance( 16 , 28 ,BufferedImage.SCALE_FAST);
int []testImgPixels = ImageUtils.getPixels(img,img.getWidth( null ),
img.getHeight( null ));
ImageUtils.displayMatrix(ImageUtils.getSymbolMatrix(testImgPixels, 2 ));
// irt.getMatchResult(ImageUtils.getPixels(bi,
// bi.getWidth(),
// bi.getHeight()));
}
}
*@(#)ImageTextRecognitor.java
*
*Thisprogramisfreesoftware;youcanredistributeitand/ormodify
*itunderthetermsoftheGNUGeneralPublicLicenseaspublishedby
*theFreeSoftwareFoundation;eitherversion3oftheLicense,or
*(atyouroption)anylaterversion.
*
*Thisprogramisdistributedinthehopethatitwillbeuseful,
*butWITHOUTANYWARRANTY;withouteventheimpliedwarrantyof
*MERCHANTABILITYorFITNESSFORAPARTICULARPURPOSE.Seethe
*GNULibraryGeneralPublicLicenseformoredetails.
*YoushouldhavereceivedacopyoftheGNUGeneralPublicLicense
*alongwiththisprogram;ifnot,writetotheFreeSoftware
*Foundation,Inc.,59TemplePlace-Suite330,Boston,MA02111-1307,USA.
*/
package cn.edu.ynu.sei.recognition;
import cn.edu.ynu.sei.recognition.util.StdModelRepository;
import cn.edu.ynu.sei.recognition.util.ImageUtils;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
/**
*Demonstraterecognitioncharactersfromaimage.
* @author 88250
* @version 1.0.0.2,Mar20,2008
*/
public class ImageTextRecognitor{
private final static long serialVersionUID = 1L ;
private StdModelRepositorysmr = new StdModelRepository();
private BufferedImagebufferedImage;
/**
*Defaultconstructor.
*/
public ImageTextRecognitor(){
try {
bufferedImage = ImageIO.read( new File( " a_yahei12.png " ));
} catch (IOExceptionex){
Logger.getLogger(StdModelRepository. class .getName()).
log(Level.SEVERE, null ,ex);
}
}
/**
*Returnthematchedcharacterwithsepecifiedimage.
* @param symbolMatrixthematrixofsepecifiedimage
* @return thecharacter
*/
// TODO:thecorealgorithm
public char getMatchResult( int [][]symbolMatrix){
char result = 0 ;
int tmpEvaluation = 100 ;
int evaluation = 0 ;
return result;
}
/**
*Mainprogramentry.
* @param argsshouldbe<code>null</code>
*/
public static void main(String[]args){
ImageTextRecognitorirt = new ImageTextRecognitor();
BufferedImagebi = irt.bufferedImage;
Imageimg = bi.getScaledInstance( 16 , 28 ,BufferedImage.SCALE_FAST);
int []testImgPixels = ImageUtils.getPixels(img,img.getWidth( null ),
img.getHeight( null ));
ImageUtils.displayMatrix(ImageUtils.getSymbolMatrix(testImgPixels, 2 ));
// irt.getMatchResult(ImageUtils.getPixels(bi,
// bi.getWidth(),
// bi.getHeight()));
}
}
测试
标准字符图像
测试字符图像
测试输出
init:deps-jar:
Compiling 2 source files to /home/daniel/Work/Sources/Java/ImageTextRecognition/build/classes
compile:
run:
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BUILD SUCCESSFUL (total time: 1 second)
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