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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<title>Tess4J - Java Wrapper for Tesseract OCR API</title>
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<body>
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<div class="Section1">
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<h2 align="center">
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Tess4J
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</h2>
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<h3>
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DESCRIPTION
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</h3>
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<p>
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Tess4J is a JNA wrapper for <a href="https://github.com/tesseract-ocr">Tesseract OCR
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API</a>; it provides character recognition support for common image formats,
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multi-page images, and PDF documents. The library has been developed and tested
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on Windows and Linux.
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</p>
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<p>
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Tess4J is released and distributed under the <a href="http://www.apache.org/licenses/LICENSE-2.0.html">
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Apache License, v2.0</a>. Its official homepage is at <a href="http://tess4j.sourceforge.net/">
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http://tess4j.sourceforge.net</a>.
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</p>
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<h3>
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SOFTWARE REQUIREMENTS
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</h3>
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<p>
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<a href="http://java.oracle.com/">Java Runtime Environment</a>, <a href="https://github.com/twall/jna">
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JNA</a>, and <a href="https://java.net/projects/jai-imageio">JAI-ImageIO</a>
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are required. <a href="http://maven.apache.org/">Apache Maven</a> and <a href="http://www.junit.org/">
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JUnit</a> are used for program building and unit testing. The Tesseract DLLs
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were built with VS2019 (v142) and therefore depend on the <a href="https://visualstudio.microsoft.com/downloads/">
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Visual C++ 2019 Redistributable Packages</a>.
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</p>
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<h3>
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INSTRUCTIONS
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</h3>
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<p>
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Tesseract 5.0.0 and Leptonica 1.79 (via Lept4J) 32- and 64-bit
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DLLs, language data for English, and sample images are bundled with the library.
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<a href="https://github.com/tesseract-ocr/tessdata">Language data packs</a> for
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Tesseract should be decompressed and placed into the <code>tessdata</code> folder.
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</p>
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<p>
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The Linux shared object library (<code>libtesseract.so</code>) equivalent to the
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DLL is available in Tesseract 5.0.0, which can be built from the <a href="https://github.com/tesseract-ocr/tesseract"
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target="_blank">source</a> with the instructions given in <a href="https://tesseract-ocr.github.io/tessdoc/Compiling"
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target="_blank">Tesseract Wiki</a>.
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</p>
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<p>
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To unit test, at the command line, execute:
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</p>
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<blockquote>
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<p>
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<code>mvn test</code>
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</p>
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</blockquote>
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<p>
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Support for PDF documents is available through either
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<a href="http://www.ghostscript.com/" target="_blank">GPL Ghostscript</a>, which should be installed and included
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in system path, or PDFBox, if Ghostscript is not available.
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</p>
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<p>
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Images to be OCRed should be scanned at resolution from at least 200 DPI (dot per
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inch) to 400 DPI in monochrome (black&white) or grayscale. Scanning at higher
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resolutions will not necessarily result in better recognition accuracy. The actual
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success rates depend greatly on the quality of the scanned image. The typical settings
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for scanning are 300 DPI and 1 bpp (bit per pixel) black&white or 8 bpp grayscale
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uncompressed TIFF or PNG format. PNG is usually smaller in size than other image
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formats and still keeps high quality due to its employing lossless data compression
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algorithms; TIFF has the advantage of the ability to contain multiple images (pages)
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in a file.
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</p>
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<p>
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Several built-in functions are also provided for merging several images or PDF files
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into a single one for convenient OCR operations, or for splitting a PDF file into
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smaller ones if it is too large, which can cause out-of-memory exceptions.
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</p>
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<h3>
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CODE EXAMPLES
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</h3>
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<p>
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The following code example shows common usage of the library. Make sure <code>tessdata</code>
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folder is populated with appropriate language data files and the <code>.jar</code>
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files are in the classpath. On Windows, the DLLs will be automatically extracted
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from <code>tess4j.jar</code> to the default temporary directory and loaded.
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</p>
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<blockquote>
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<pre>
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package net.sourceforge.tess4j.example;
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import java.io.File;
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import net.sourceforge.tess4j.*;
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public class TesseractExample {
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public static void main(String[] args) {
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// ImageIO.scanForPlugins(); // for server environment
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File imageFile = new File("eurotext.tif");
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ITesseract instance = new Tesseract(); // JNA Interface Mapping
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// ITesseract instance = new Tesseract1(); // JNA Direct Mapping
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// File tessDataFolder = LoadLibs.extractTessResources("tessdata"); // Maven build only; only English data bundled
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// instance.setDatapath(tessDataFolder.getPath());
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try {
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String result = instance.doOCR(imageFile);
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System.out.println(result);
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} catch (TesseractException e) {
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System.err.println(e.getMessage());
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}
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}
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}
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</pre>
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</blockquote>
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<h3>
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DOCUMENTATIONS
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</h3>
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<p>
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Please visit the website for the library's <a href="http://tess4j.sf.net/docs/">documentations</a>
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</p>
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<hr />
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</div>
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</body>
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</html>
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