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。

Java代码  

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