Apache Tika提取扫描PDF文件 [英] Apache Tika extract scanned PDF files

问题描述

我在使用Apache TIKA（版本1.10）时遇到了一些麻烦。我得到了一些PDF文件，这些文件只是扫描过的纸片。这意味着每个页面只是一个图像。我的目标是提取PDF文件的文本。

i'm having some troubles using Apache TIKA (version 1.10). I got some PDF files which are just scanned pieces of paper. That means each page is just an image. My goal is to extract the text of the PDF files anyway.

我的tesseract设置正确，提取JPG和PNG文件就像一个魅力。我正在使用的代码看起来像那样（不介意缺少异常处理）：

My tesseract is set up correctly and extracting JPG and PNG files works like a charm. The code i'm using looks like that (don't mind the missing excetion handling):

public String extractText(InputStream stream) {
    AutoDetectParser parser = new AutoDetectParser();
    BodyContentHandler handler = new BodyContentHandler(Integer.MAX_VALUE);
    Metadata metadata = new Metadata();
    ParseContext context = new ParseContext();
    parser.parse(stream, handler, metadata, context);
    String text = handler.toString();
    return text;
}

我搜索了很多，但我找不到任何适用于我的解决方案。我已经尝试了 PDFParserConfig 类的 setExtractInlineImages 方法，但这没有改变。
使用自定义 ParsingEmbeddedDocumentExtractor 提取嵌入文档确实提取了doc文件的嵌入资源，但没有提取我的PDF文件。

I searched a lot but i didn't find any solutions that work for me. I already tried the setExtractInlineImages method of the PDFParserConfig class but this didn't change a thing. Extracting embedded documents using a custom ParsingEmbeddedDocumentExtractor did extract embedded resources of a doc file but not for my PDF files.

如果你们中的任何人都可以提供一些帮助那就太棒了：）

It would be awesome if anyone of you could provide some help :)

推荐答案

Tim Allison 带来了解决方案：

Parser parser = new AutoDetectParser();
BodyContentHandler handler = new BodyContentHandler(Integer.MAX_VALUE);

TesseractOCRConfig config = new TesseractOCRConfig();
PDFParserConfig pdfConfig = new PDFParserConfig();
pdfConfig.setExtractInlineImages(true);

ParseContext parseContext = new ParseContext();
parseContext.set(TesseractOCRConfig.class, config);
parseContext.set(PDFParserConfig.class, pdfConfig);
parseContext.set(Parser.class, parser); //need to add this to make sure recursive parsing happens!

parser.parse(stream, handler, new Metadata(), parseContext);

这对我有用：）

编辑：
以下是完整的解决方案：

Here is the complete solution:

import org.apache.tika.exception.TikaException;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.parser.AutoDetectParser;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.parser.Parser;
import org.apache.tika.parser.ocr.TesseractOCRConfig;
import org.apache.tika.parser.pdf.PDFParserConfig;
import org.apache.tika.sax.BodyContentHandler;
import org.xml.sax.SAXException;

import java.io.FileInputStream;
import java.io.IOException;

/**
 * @since 8/26/16
 */
public class Sample {
    public static void main(String[] args)
            throws IOException, TikaException, SAXException {
        Parser parser = new AutoDetectParser();
        BodyContentHandler handler = new BodyContentHandler(Integer.MAX_VALUE);

        TesseractOCRConfig config = new TesseractOCRConfig();
        PDFParserConfig pdfConfig = new PDFParserConfig();
        pdfConfig.setExtractInlineImages(true);

        ParseContext parseContext = new ParseContext();
        parseContext.set(TesseractOCRConfig.class, config);
        parseContext.set(PDFParserConfig.class, pdfConfig);
        //need to add this to make sure recursive parsing happens!
        parseContext.set(Parser.class, parser);

        FileInputStream stream = new FileInputStream("samplepdf.pdf");
        Metadata metadata = new Metadata();
        parser.parse(stream, handler, metadata, parseContext);
        System.out.println(metadata);
        String content = handler.toString();
        System.out.println("===============");
        System.out.println(content);
        System.out.println("Done");
    }
}

Maven依赖项：

<dependencies>
    <dependency>
      <groupId>org.apache.tika</groupId>
      <artifactId>tika-parsers</artifactId>
      <version>1.13</version>
    </dependency>
    <dependency>
      <groupId>com.levigo.jbig2</groupId>
      <artifactId>levigo-jbig2-imageio</artifactId>
      <version>1.6.5</version>
    </dependency>
  </dependencies>

这篇关于Apache Tika提取扫描PDF文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！