通过Tesseract进行OCR识别

前提:安装好Tesseract并下载好简体中文语言包,本文在Windows上验证过,需要安装包可以关注 公号  easy4java获取

1.配置maven依赖

        <!-- pdf 解析-->
        <dependency>
            <groupId>org.apache.pdfbox</groupId>
            <artifactId>pdfbox</artifactId>
            <version>2.0.1</version>
        </dependency>
        <dependency>
            <groupId>org.apache.pdfbox</groupId>
            <artifactId>fontbox</artifactId>
            <version>2.0.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.pdfbox</groupId>
            <artifactId>jempbox</artifactId>
            <version>1.8.11</version>
        </dependency>
        <dependency>
            <groupId>org.apache.pdfbox</groupId>
            <artifactId>xmpbox</artifactId>
            <version>2.0.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.pdfbox</groupId>
            <artifactId>preflight</artifactId>
            <version>2.0.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.pdfbox</groupId>
            <artifactId>pdfbox-tools</artifactId>
            <version>2.0.0</version>
        </dependency>

      <!-- Tesseract OCR-->
        <dependency>
            <groupId>net.sourceforge.tess4j</groupId>
            <artifactId>tess4j</artifactId>
            <version>4.5.4</version>
        </dependency>

2.Java代码实现

/**
 * @Author:admin
 * @Date: 2025/4/21  15:53
 * @Description admin
 * @Version 1.0.0
 */

import net.sourceforge.tess4j.Tesseract;
import net.sourceforge.tess4j.TesseractException;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDPage;
import org.apache.pdfbox.pdmodel.PDResources;
import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class PDFTextRecognition {
    public static void main(String[] args) {
        try {
            long start = System.currentTimeMillis();
            // 1. 读取PDF文件
            PDDocument document = PDDocument.load(new File("C:\\Users\\admin\\Desktop\\test.pdf"));

            PDPage page = document.getPage(0);
            PDResources resource = page.getResources();
            Iterable<COSName> xobjects = resource.getXObjectNames();
            if (xobjects != null) {
                Iterator<COSName> imageItr = xobjects.iterator();
                while (imageItr.hasNext()) {
                    COSName imageName = imageItr.next();
                    boolean isImage = resource.isImageXObject(imageName);
                    if (isImage) {
                        PDImageXObject ixt = (PDImageXObject) resource.getXObject(imageName);
                        // 3. 使用OCR识别图像中的文字
                        Tesseract tesseract = new Tesseract();
                        //从官网下载简体中文语言包
                        tesseract.setLanguage("chi_sim");
                        //要语言包放在安装目录下tessdata目录下
                        tesseract.setDatapath("E:\\software\\tesseract\\tessdata"); // 设置Tesseract的语言数据文件路径

                        //截取要识别的图片区域,减少无效区域的识别,如果有需要可以进行放大操作(提高识别的准确率)
                        BufferedImage image = ixt.getImage();
                        BufferedImage subImage = image.getSubimage(0, 0, 2000, 800);
                        String text = tesseract.doOCR(subImage);

                        extractContractNumber(text);
                        System.out.println(text);
                    }
                }
            }

            // 关闭PDF文档
            document.close();
            long end = System.currentTimeMillis();
            System.out.println("消费时长" + (end - start) / 1000 + "s");
        } catch (IOException | TesseractException e) {
            e.printStackTrace();
        }
    }

    /**
     * 通过正则解析识别出的内容
     *
     * @param text
     */
    public static void extractContractNumber(String text) {
        // 正则表达式模式
        Pattern supplierPattern = Pattern.compile("供\\s*方\\s*[:：]\\s*(.*?)\\s*合\\s*同\\s*编\\s*号");
        Pattern contractNoPattern = Pattern.compile("合\\s*同\\s*编\\s*号\\s*[:：]\\s*(\\w+)");
        Pattern buyerPattern = Pattern.compile("需\\s*方\\s*[,，]\\s*(.*?)\\s*签\\s*订\\s*日\\s*期");

        // 匹配供方
        Matcher supplierMatcher = supplierPattern.matcher(text);
        if (supplierMatcher.find()) {
            String supplier = supplierMatcher.group(1).replaceAll("\\s+", "");
            System.out.println("供方: " + supplier);
        }

        // 匹配合同编号
        Matcher contractNoMatcher = contractNoPattern.matcher(text);
        if (contractNoMatcher.find()) {
            String contractNo = contractNoMatcher.group(1);
            System.out.println("合同编号: " + contractNo);
        }

        // 匹配需方
        Matcher buyerMatcher = buyerPattern.matcher(text);
        if (buyerMatcher.find()) {
            String buyer = buyerMatcher.group(1).replaceAll("\\s+", "");
            System.out.println("需方: " + buyer);
        }
    }
}