Java OCR tesseract 图像智能字符识别技术 Java代码实现
接着上一篇OCR所说的，上一篇给大家介绍了tesseract 在命令行的简单用法，当然了要继承到我们的程序中，还是需要代码实现的，下面给大家分享下java实现的例子。
拿代码扫描上面的图片，然后输出结果。主要思想就是利用Java调用系统任务。
下面是核心代码：
/*** */package cn.jorcen.dropins.tesseract;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.UnsupportedEncodingException;import java.util.LinkedList;import java.util.List;import mons.io.IOUtils;import org.apache.log4j.Logger;/*** * * @author mjorcen* @email mjorcen@* @dateTime Jun 19, 3:42:16 PM* @version 1*/public class TesseractOCRUtil {static Logger logger = Logger.getLogger(TesseractOCRUtil.class);static String path = "E:/data/Users/Administrator/Desktop/ocr/spelling";public static void main(String[] args) throws Exception {File file = new File(path);String[] strs = file.list();for (String string : strs) {File iFile = new File(path, string);if (iFile.isFile()) {parseImage(new File(file.getAbsolutePath(), string), new File(path + "/tmp", iFile.getName()));}}System.exit(0);}public static String parseImage(File file, File targetFile)throws Exception {ClearImageUtil.cleanImage(file, targetFile);return parseImageOnNoClear(targetFile);}public static String parseImageOnNoClear(File file) throws Exception {try {logger.debug("image is " + file.getAbsolutePath());// ClearImageHelper.cleanImage(file, filename);// 构造命令// List<String> cmd = new LinkedList<String>();// cmd.add("tesseract");// cmd.add(file.getAbsolutePath());// cmd.add(file.getAbsolutePath());// cmd.add(" ");// cmd.add("-l");// cmd.add(" ");// cmd.add("normal");// logger.debug(cmd);// System.out.println(cmd);// ProcessBuilder pb = new ProcessBuilder(cmd);// pb.redirectErrorStream(true);// pb.directory(new File(path));// Process p = pb.start();Runtime run = Runtime.getRuntime();Process p = run.exec("cmd.exe /c tesseract "+ file.getAbsolutePath() + " " + file.getAbsolutePath()+ " -l normal");getConsole(p);String sb = getResult(new File(file.getAbsolutePath() + ".txt"));return sb.toString();} catch (Exception e) {logger.error(e);return null;} finally {}}private static String getResult(File file) throws FileNotFoundException,UnsupportedEncodingException, IOException {StringBuilder sb = new StringBuilder();// 取得结果的输出流InputStream resultIs = new FileInputStream(file);// 用一个读输出流类去读InputStreamReader resultIsr = new InputStreamReader(resultIs, "utf-8");// 用缓冲器读行BufferedReader resultBr = new BufferedReader(resultIsr);String line;// 直到读完为止while ((line = resultBr.readLine()) != null) {logger.debug(line);sb.append(line);}return sb.toString();}private static void getConsole(Process p)throws UnsupportedEncodingException, IOException {// 取得命令结果的输出流InputStream fis = p.getInputStream();// 用一个读输出流类去读InputStreamReader isr = new InputStreamReader(fis, "utf-8");// 用缓冲器读行BufferedReader br = new BufferedReader(isr);String line = null;// 直到读完为止while ((line = br.readLine()) != null) {// System.out.println(line); }}public static void test() {try {List<String> cmd = new LinkedList<String>();cmd.add("javac");cmd.add("PB.java");ProcessBuilder pb = new ProcessBuilder(cmd);pb.redirectErrorStream(true);pb.directory(new File("E:/test"));Process p = pb.start();// 取得命令结果的输出流InputStream fis = p.getInputStream();// 用一个读输出流类去读InputStreamReader isr = new InputStreamReader(fis, "utf-8");// 用缓冲器读行BufferedReader br = new BufferedReader(isr);String line = null;// 直到读完为止while ((line = br.readLine()) != null) {logger.debug(line);}} catch (Exception e) {logger.error(e);}}}
结果如下:
uHx7,IXQO,\1ZYP,ZVBO,3237,5SYQ~,,87YF,\8KDN,CGPC,\c\IG\N,F\Z TA,J 9pc,Lpza,NBGC,N QW8,onwz,ox XJ,\P9FM,P PR鈥楿,QRG\I\,,RAZ v\,504i,VGPH,VPCI,\\I\M I,鈥楳J1,Y6H9\,Y OGP,
对比第一张图片， 不是很完美~哈哈 ，当然了如果你只需要实现验证码的读写，那么上面就足够了。下面继续普及图像处理的知识。
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当然了，有时候图片被扭曲或者模糊的很厉害，很不容易识别，所以下面我给大家介绍一个去噪的辅助类， 能稍做优化，先看下效果图。
package cn.c.test3;import java.awt.Color;import java.awt.image.BufferedImage;import java.io.File;import java.io.IOException;import javax.imageio.ImageIO;public class ClearImageHelper {public static void main(String[] args) throws IOException {File testDataDir = new File("E:\\test\\code");final String destDir = testDataDir.getAbsolutePath() + "/tmp";for (File file : testDataDir.listFiles()) {cleanImage(file, destDir);}}/*** * @param sfile* 需要去噪的图像* @param destDir* 去噪后的图像保存地址* @throws IOException*/public static void cleanImage(File sfile, String destDir)throws IOException {File destF = new File(destDir);if (!destF.exists()) {destF.mkdirs();}BufferedImage bufferedImage = ImageIO.read(sfile);int h = bufferedImage.getHeight();int w = bufferedImage.getWidth();// 灰度化int[][] gray = new int[w][h];for (int x = 0; x < w; x++) {for (int y = 0; y < h; y++) {int argb = bufferedImage.getRGB(x, y);// 图像加亮（调整亮度识别率非常高）int r = (int) (((argb >> 16) & 0xFF) * 1.1 + 30);int g = (int) (((argb >> 8) & 0xFF) * 1.1 + 30);int b = (int) (((argb >> 0) & 0xFF) * 1.1 + 30);if (r >= 255) {r = 255;}if (g >= 255) {g = 255;}if (b >= 255) {b = 255;}gray[x][y] = (int) Math.pow((Math.pow(r, 2.2) * 0.2973 + Math.pow(g, 2.2)* 0.6274 + Math.pow(b, 2.2) * 0.0753), 1 / 2.2);}}// 二值化int threshold = ostu(gray, w, h);BufferedImage binaryBufferedImage = new BufferedImage(w, h,BufferedImage.TYPE_BYTE_BINARY);for (int x = 0; x < w; x++) {for (int y = 0; y < h; y++) {if (gray[x][y] > threshold) {gray[x][y] |= 0x00FFFF;} else {gray[x][y] &= 0xFF0000;}binaryBufferedImage.setRGB(x, y, gray[x][y]);}}// 矩阵打印for (int y = 0; y < h; y++) {for (int x = 0; x < w; x++) {if (isBlack(binaryBufferedImage.getRGB(x, y))) {System.out.print("*");} else {System.out.print(" ");}}System.out.println();}ImageIO.write(binaryBufferedImage, "jpg",new File(destDir, sfile.getName()));}public static boolean isBlack(int colorInt) {Color color = new Color(colorInt);if (color.getRed() + color.getGreen() + color.getBlue() <= 300) {return true;}return false;}public static boolean isWhite(int colorInt) {Color color = new Color(colorInt);if (color.getRed() + color.getGreen() + color.getBlue() > 300) {return true;}return false;}public static int isBlackOrWhite(int colorInt) {if (getColorBright(colorInt) < 30 || getColorBright(colorInt) > 730) {return 1;}return 0;}public static int getColorBright(int colorInt) {Color color = new Color(colorInt);return color.getRed() + color.getGreen() + color.getBlue();}public static int ostu(int[][] gray, int w, int h) {int[] histData = new int[w * h];// Calculate histogramfor (int x = 0; x < w; x++) {for (int y = 0; y < h; y++) {int red = 0xFF & gray[x][y];histData[red]++;}}// Total number of pixelsint total = w * h;float sum = 0;for (int t = 0; t < 256; t++)sum += t * histData[t];float sumB = 0;int wB = 0;int wF = 0;float varMax = 0;int threshold = 0;for (int t = 0; t < 256; t++) {wB += histData[t]; // Weight Backgroundif (wB == 0)continue;wF = total - wB; // Weight Foregroundif (wF == 0)break;sumB += (float) (t * histData[t]);float mB = sumB / wB; // Mean Backgroundfloat mF = (sum - sumB) / wF; // Mean Foreground// Calculate Between Class Variancefloat varBetween = (float) wB * (float) wF * (mB - mF) * (mB - mF);// Check if new maximum foundif (varBetween > varMax) {varMax = varBetween;threshold = t;}}return threshold;}}
