Java 识别简单验证码
最近在调研用JAVA识别图片中的数字，查看了一些资料，在此转载一篇识别简单验证码的文章。该方法只适用于字体统一规整的、没有扭曲拉伸的简单数字验证码的识别，形如 
这样的图片验证码。
引用jar包：jai-core-1.1.3.jar 、jai-codec-1.1.3.jar
算法思路如下：
1. 根据验证码图片的分析结果（主要是分析数字所在的像素位置），对其进行分割，分割成包含单个数字的图片。
2. 对分割后的图片先进行灰度化，然后二值化，生成单色位图。
3. 读取单色位图的像素点，转换为 0 ， 1 数组。
4.把该数组和提前生成好的0-9的字模数组进行比对，取匹配率最大的那个字模所对应的数字。
package com;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.InputStream;
import javax.imageio.ImageIO;
import javax.media.jai.JAI;
import javax.media.jai.RenderedOp;
/**
* 数字验证码识别器（用于识别xxx系统的图片验证码）
*
* 算法如下： 分析验证码图片结构，将其分隔成4个独立的数字图片，把四个独立的数字图片处理成单色位图。
* 把单色位图转换为0、1数组，然后分别和0-9的字模进行匹配，得到图片上的数字信息。
*
* @version 1.0 2009-7-7
* @author huangyuanmu
* @since JDK 1.5.0_8
*/
public class NumberVerificationCodeIdentifier {
static
{
System.setProperty("com.sun.media.jai.disableMediaLib", "true");
}
// 数字模板 0-9
static int[][] value = {
// num 0;
{ 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0,
0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1,
0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0,
0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0,
0, 1, 1, 1, 0, 0 },
// num 1
{ 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0,
0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0,
0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0 }, // num2 { 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0 }, // num3 { 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0 }, // num4 { 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0 }, // num5 { 0, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0 }, // num6 { 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0 }, // num7 { 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0 }, // num8 { 0, 0, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0 }, // num9 { 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0 } }; /** * 识别图像 * * @author huangyuanmu 2009-7-14 * @param byteArray * @return * @throws Exception */ public static String recognize(byte[] byteArray) throws Exception { InputStream is = new ByteArrayInputStream(byteArray); BufferedImage image = ImageIO.read(is); return recognize(image); } /** * 识别图像 * * @author huangyuanmu 2009-7-14 * @param image * @return * @throws Exception */ public static String recognize(BufferedImage image) throws Exception { StringBuffer sb = new StringBuffer(""); BufferedImage newim[] = new BufferedImage[4]; if(null == image){ throw new RuntimeException("iamage为null"); } // 将图像分成四块，因为要处理的文件有四个数字。 newim[0] = generateSingleColorBitMap(image.getSubimage(2, 1, 8, 11)); newim[1] = generateSingleColorBitMap(image.getSubimage(11, 1, 8, 11)); newim[2] = generateSingleColorBitMap(image.getSubimage(20, 1, 8, 11)); newim[3] = generateSingleColorBitMap(image.getSubimage(29, 1, 8, 11)); for (int k = 0; k < 4; k++) { int iw = newim[k].getWidth(null); int ih = newim[k].getHeight(null); int[] pix = new int[iw * ih]; // 因为是二值图像，这里的方法将像素读取出来的同时，转换为0，1的图像数组。 for (int i = 0; i < ih; i++) { for (int j = 0; j < iw; j++) { pix[i * (iw) + j] = newim[k].getRGB(j, i); if (pix[i * (iw) + j] == -1) pix[i * (iw) + j] = 0; else pix[i * (iw) + j] = 1; } } // 得到像匹配的数字。 int r = getMatchNum(pix); sb.append(r); } return sb.toString(); } /** * 把单色位图转换成的0、1数组和字模数组进行比较，返回匹配的数字 * * @author huangyuanmu 2009-7-7 * @param pix * @return */ private static int getMatchNum(int[] pix) { int result = -1; int temp = 100; int x; for (int k = 0; k <= 9; k++) { x = 0; for (int i = 0; i < pix.length; i++) { x = x + Math.abs(pix[i] - value[k][i]); } if(x == 0){ result = k; break; }else if (x < temp){ temp = x; result = k; } } return result; } /** * 把彩色图像转换单色图像 * * @author huangyuanmu 2009-7-7 * @param colorImage * @return */ private static BufferedImage generateSingleColorBitMap(Image colorImage) { BufferedImage image = new BufferedImage(8, 11, BufferedImage.TYPE_BYTE_GRAY); Graphics g = image.getGraphics(); g.drawImage(colorImage, 0, 0, null); g.dispose(); RenderedOp ro = JAI.create("binarize", image, new Double(100)); BufferedImage bi = ro.getAsBufferedImage(); return bi; } /** * 测试 * * @author huangyuanmu 2009-7-7 * @param args */ public static void main(String args[]) throws Exception { String s = recognize(ImageIO.read(new File("D:\\testNum2.jpeg"))); System.out.println("recognize result" + s); }}
复杂的验证码识别技术就相当复杂了，个人也没有精力去研究了，使用现成的OCR软件不失为一个便捷的方法。tesseract是一个不错的选择，它是惠普公
