Simple recognition of 4-bit cpatcha of NJU bras

captcha.java

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.image.ImageObserver;
import java.awt.image.PixelGrabber;
import java.io.IOException;
import java.net.*;

import javax.imageio.ImageIO;
import javax.swing.JFrame;

//仅针对PNJU的简单验证码，测试通过率95%以上
public class captcha extends JFrame {

	private static final String URL = "http://p.nju.edu.cn/portal/img.html";
	Image img = null;
	int num1, num2, num3, num4;// 有效灰度像素数
	int cnum1, cnum2, cnum3, cnum4;// 画Y轴线与数字交叉次数
	int lnum1, lnum2, lnum3, lnum4;// 画Y轴线与数字重叠点数 判断2、3
	Color color;

	public captcha() {
		setVisible(true);
		setSize(200, 200);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		new Thread(new Runnable() {
			public void run() {
				while (true) {
					try {
						Thread.sleep(200);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					repaint();
				}
			}
		}).start();
		;
	}

	@Override
	public void paint(Graphics g) {
		g.drawImage(img, 0, 40, 160, 70, this);
		g.setColor(Color.black);
		// 分割区域线
		g.drawLine((int) (10 * 2), 0, (int) (10 * 2), 200);
		g.drawLine((int) (26 * 2), 0, (int) (26 * 2), 200);
		g.drawLine((int) (42 * 2), 0, (int) (42 * 2), 200);
		g.drawLine((int) (59 * 2), 0, (int) (59 * 2), 200);
		g.drawLine((int) (75 * 2), 0, (int) (75 * 2), 200);
	}

	public Image load() {
		img = null;
		try {
			URL url = new URL(URL);
			img = ImageIO.read(url);
		} catch (IOException e) {
			e.printStackTrace();
		}
		return img;
	}

	public void analyze(Image image) {
		int err = 0;
		int x = 0;
		int width = image.getWidth(null);
		int height = image.getHeight(null);
		int pixels[] = new int[width * height];
		PixelGrabber pg = new PixelGrabber(image, 0, 0, width, height, pixels,
				0, width);
		try {
			pg.grabPixels();
		} catch (InterruptedException e) {
			System.err.println("interrupted waiting for pixels!");
			e.printStackTrace();
		}
		if ((pg.getStatus() & ImageObserver.ABORT) != 0) {
			System.err.println("image fetch aborted or errored");
		}
		// y
		for (int i = 0; i < height; i++) {
			// x
			for (int j = 0; j < width; j++) {
				int n = i * width + j;
				if ((j >= 0 && j <= 10) || (j <= 79 && j >= 76)) {
					continue;//非数字区域 跳过
				}
				if (getP(pixels[n]) != 442) {//有效像素点的总RGB灰度为442 蓝色 
					continue;
				}
				if (j >= 10 && j <= 25) {// 第一个数字
					num1++;
				} else if (j >= 26 && j <= 42) {// 第二个数字
					num2++;
				} else if (j >= 43 && j <= 59) {// 第三个数字
					num3++;
				} else if (j >= 60 && j <= 75) {// 第四个数字
					num4++;
				} else {
					err++;
				}
			}
		}
		cnum1 = getCrossTime(17, height, width, pixels);// 数字一与x=17交错次数
		lnum1 = getTime(21, height, width, pixels);//与x=21像素点重叠次数
		cnum2 = getCrossTime(33, height, width, pixels);// 数字二与x=33交错次数
		lnum2 = getTime(37, height, width, pixels);
		cnum3 = getCrossTime(50, height, width, pixels);// 数字三与x=50交错次数
		lnum3 = getTime(54, height, width, pixels);
		cnum4 = getCrossTime(67, height, width, pixels);// 数字四与x=67交错次数
		lnum4 = getTime(71, height, width, pixels);
		System.out.println("num1:" + num1);
		System.out.println("cnum1:" + cnum1);
		System.out.println("num2:" + num2);
		System.out.println("cnum2:" + cnum2);
		System.out.println("num3:" + num3);
		System.out.println("cnum3:" + cnum3);
		System.out.println("num4:" + num4);
		System.out.println("cnum4:" + cnum4);
		System.out.println("lnum1:" + lnum1);
		System.out.println("lnum2:" + lnum2);
		System.out.println("lnum3:" + lnum3);
		System.out.println("lnum4:" + lnum4);
		System.out.println("err:" + err);
		System.out.println("result:" + getInt(num1, cnum1, lnum1)
				+ getInt(num2, cnum2, lnum2) + getInt(num3, cnum3, lnum3)
				+ getInt(num4, cnum4, lnum4));

	}

	public int getCrossTime(int x, int height, int width, int[] pixels) {
		boolean in = false;
		int time = 0;
		int n = 0;
		for (int i = 0; i < height; i++) {
			n = i * width + x;
			if (getP(pixels[n]) == 442) {
				if (!in) {
					in = true;
					time++;
				}
			} else {
				if (in) {
					in = false;
				}
			}
		}
		return time;
	}

	public int getTime(int x, int height, int width, int[] pixels) {
		int time = 0;
		int n = 0;
		for (int i = 0; i < height; i++) {
			n = i * width + x;
			if (getP(pixels[n]) == 442) {
				time++;
			}
		}
		return time >= 12 ? 3 : 2;
	}

	public int getInt(int num, int cnum, int lnum) {
		switch (num) {
		case 81:
			return 1;
		case 96:
		case 100:
			return 2;
		case 97:
			return 3;
		case 111:
		case 101:
			return 4;
		case 105:
		case 114:
		case 95:
			return 5;
		case 122:
		case 116:
			return 6;
		case 76:
		case 72:
		case 82:
			return 7;
		case 123:
		case 128:
		case 129:
			return 8;
		case 117:
		case 119:
			return 9;
		case 125:
		case 112:
			return 0;

			// 下面是几个出现映射重叠的数字 用Y-cross-time和Y-time进行二次判别
		case 92:
		case 98:
			switch (cnum) {
			case 1:
				return 1;
			case 3:
				switch (lnum) {
				case 2:
					return 2;
				case 3:
					return 3;
				default:
					return -1;
				}
			default:
				return -1;
			}
		case 120:
			switch (cnum) {
			case 2:
				return 0;
			case 3:
				return 6;
			default:
				return -1;
			}
		case 107:
			switch (cnum) {
			case 2:
				return 4;
			case 3:
				return 9;
			default:
				return -1;
			}
		default:
			return -1;
		}
	}

	// 得到像素点rgb总值
	public int getP(int c) {
		return getR(c) + getG(c) + getB(c);
	}

	public int getR(int c) {
		return c >> 16 & 0xFF;
	}

	public int getG(int c) {
		return c >> 8 & 0xFF;
	}

	public int getB(int c) {
		return c & 0xFF;
	}

	public static void main(String[] args) {
		captcha captcha = new captcha();
		captcha.analyze(captcha.load());
	}
}