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JAVA使用Tess4J进行ocr识别

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Tess4J是对Tesseract OCR API.的Java JNA 封装。使java能够通过调用Tess4J的API来使用Tesseract OCR。支持的格式:TIFF,JPEG,GIF,PNG,BMP,JPEG,and PDF
Tesseract 的github地址:https://github.com/tesseract-ocr/tesseract
Tess4J的github地址:https://github.com/nguyenq/tess4j

Tess4J API 提供的功能:
1、直接识别支持的文件
2、识别图片流
3、识别图片的某块区域
4、将识别结果保存为 TEXT/ HOCR/ PDF/ UNLV/ BOX
5、通过设置取词的等级,提取识别出来的文字
6、获得每一个识别区域的具体坐标范围
7、调整倾斜的图片
8、裁剪图片
9、调整图片分辨率
10、从粘贴板获得图像
11、克隆一个图像(目的:创建一份一模一样的图片,与原图在操作修改上,不相 互影响)
12、图片转换为二进制、黑白图像、灰度图像
13、反转图片颜色
demo.java:

    /**
     * Test of doOCR method, of class Tesseract.
     * 根据图片文件进行识别
     * @throws Exception while processing image.
     */
    @Test
    public void testDoOCR_File() throws Exception {
        logger.info("doOCR on a jpg image");
        File imageFile = new File(this.testResourcesDataPath, "ocr.png");
        //set language
        instance.setDatapath(testResourcesLanguagePath);
        instance.setLanguage("chi_sim");
        String result = instance.doOCR(imageFile);
        logger.info(result);
    }

    /**
     * Test of doOCR method, of class Tesseract.
     * 根据图片流进行识别
     * @throws Exception while processing image.
     */
    @Test
    public void testDoOCR_BufferedImage() throws Exception {
        logger.info("doOCR on a buffered image of a PNG");
        File imageFile = new File(this.testResourcesDataPath, "ocr.png");
        BufferedImage bi = ImageIO.read(imageFile);

        //set language
        instance.setDatapath(testResourcesLanguagePath);
        instance.setLanguage("chi_sim");

        String result = instance.doOCR(bi);
        logger.info(result);
    }

    /**
     * Test of getSegmentedRegions method, of class Tesseract.
     * 得到每一个划分区域的具体坐标
     * @throws java.lang.Exception
     */
    @Test
    public void testGetSegmentedRegions() throws Exception {
        logger.info("getSegmentedRegions at given TessPageIteratorLevel");
        File imageFile = new File(testResourcesDataPath, "ocr.png");
        BufferedImage bi = ImageIO.read(imageFile);
        int level = TessPageIteratorLevel.RIL_SYMBOL;
        logger.info("PageIteratorLevel: " + Utils.getConstantName(level, TessPageIteratorLevel.class));
        List<Rectangle> result = instance.getSegmentedRegions(bi, level);
        for (int i = 0; i < result.size(); i++) {
            Rectangle rect = result.get(i);
            logger.info(String.format("Box[%d]: x=%d, y=%d, w=%d, h=%d", i, rect.x, rect.y, rect.width, rect.height));
        }

        assertTrue(result.size() > 0);
    }


    /**
     * Test of doOCR method, of class Tesseract.
     * 根据定义坐标范围进行识别
     * @throws Exception while processing image.
     */
    @Test
    public void testDoOCR_File_Rectangle() throws Exception {
        logger.info("doOCR on a BMP image with bounding rectangle");
        File imageFile = new File(this.testResourcesDataPath, "ocr.png");
        //设置语言库
        instance.setDatapath(testResourcesLanguagePath);
        instance.setLanguage("chi_sim");
        //划定区域
        // x,y是以左上角为原点,width和height是以xy为基础
        Rectangle rect = new Rectangle(84, 21, 15, 13);
        String result = instance.doOCR(imageFile, rect);
        logger.info(result);
    }

    /**
     * Test of createDocuments method, of class Tesseract.
     * 存储结果
     * @throws java.lang.Exception
     */
    @Test
    public void testCreateDocuments() throws Exception {
        logger.info("createDocuments for png");
        File imageFile = new File(this.testResourcesDataPath, "ocr.png");
        String outputbase = "target/test-classes/docrenderer-2";
        List<RenderedFormat> formats = new ArrayList<RenderedFormat>(Arrays.asList(RenderedFormat.HOCR, RenderedFormat.TEXT));

        //设置语言库
        instance.setDatapath(testResourcesLanguagePath);
        instance.setLanguage("chi_sim");

        instance.createDocuments(new String[]{imageFile.getPath()}, new String[]{outputbase}, formats);
    }

    /**
     * Test of getWords method, of class Tesseract.
     * 取词方法
     * @throws java.lang.Exception
     */
    @Test
    public void testGetWords() throws Exception {
        logger.info("getWords");
        File imageFile = new File(this.testResourcesDataPath, "ocr.png");

        //设置语言库
        instance.setDatapath(testResourcesLanguagePath);
        instance.setLanguage("chi_sim");

        //按照每个字取词
        int pageIteratorLevel = TessPageIteratorLevel.RIL_SYMBOL;
        logger.info("PageIteratorLevel: " + Utils.getConstantName(pageIteratorLevel, TessPageIteratorLevel.class));
        BufferedImage bi = ImageIO.read(imageFile);
        List<Word> result = instance.getWords(bi, pageIteratorLevel);

        //print the complete result
        for (Word word : result) {
            logger.info(word.toString());
        }
    }

    /**
     * Test of Invalid memory access.
     * 处理倾斜
     * @throws Exception while processing image.
     */
    @Test
    public void testDoOCR_SkewedImage() throws Exception {
        //设置语言库
        instance.setDatapath(testResourcesLanguagePath);
        instance.setLanguage("chi_sim");

        logger.info("doOCR on a skewed PNG image");
        File imageFile = new File(this.testResourcesDataPath, "ocr_skewed.jpg");
        BufferedImage bi = ImageIO.read(imageFile);
        ImageDeskew id = new ImageDeskew(bi);
        double imageSkewAngle = id.getSkewAngle(); // determine skew angle
        if ((imageSkewAngle > MINIMUM_DESKEW_THRESHOLD || imageSkewAngle < -(MINIMUM_DESKEW_THRESHOLD))) {
            bi = ImageHelper.rotateImage(bi, -imageSkewAngle); // deskew image
        }

        String result = instance.doOCR(bi);
        logger.info(result);
    }

Tess4JDemo码云地址:https://gitee.com/zhaohuihbwj/Tess4JDemo

 

Java OCR文字识别(Tess4J)

       OCR (Optical Character Recognition,光学字符识别)是指电子设备(例如扫描仪或数码相机)检查纸上打印的字符,通过检测暗、亮的模式确定其形状,然后用字符识别方法将形状翻译成计算机文字的过程;即,针对印刷体字符,采用光学的方式将纸质文档中的文字转换成为黑白点阵的图像文件,并通过识别软件将图像中的文字转换成文本格式,供文字处理软件进一步编辑加工的技术。如何除错或利用辅助信息提高识别正确率,是OCR最重要的课题,ICR(Intelligent Character Recognition)的名词也因此而产生。衡量一个OCR系统性能好坏的主要指标有:拒识率、误识率、识别速度、用户界面的友好性,产品的稳定性,易用性及可行性等。

       Tess4J是对google tesseract ocr的java库的一种实现

1.maven添加依赖

 

<!-- https://mvnrepository.com/artifact/net.sourceforge.tess4j/tess4j -->
<dependency>
    <groupId>net.sourceforge.tess4j</groupId>
    <artifactId>tess4j</artifactId>
    <version>3.2.1</version>
</dependency>
2.工具类编辑

 

 

/**
 * tesseract for javaocrOptical Character Recognition,光学字符识别)
* 工具类
* @author wind
 */
public class Tess4jUtils {
    /**
     * 从图片中提取文字,默认设置英文字库,使用classpath目录下的训练库
* @param path
* @return
*/
public static String readChar(String path){
        // JNA Interface Mapping
        ITesseract instance = new Tesseract();
        // JNA Direct Mapping
        // ITesseract instance = new Tesseract1();
        File imageFile = new File(path);
        //In case you don‘t have your own tessdata, let it also be extracted for you
        //这样就能使用classpath目录下的训练库了
        File tessDataFolder = LoadLibs.extractTessResources("tessdata");
        //Set the tessdata path
        instance.setDatapath(tessDataFolder.getAbsolutePath());
        //英文库识别数字比较准确
        instance.setLanguage(Const.ENG);
        return getOCRText(instance, imageFile);
    }

    /**
     * 从图片中提取文字
* @param path 图片路径
* @param dataPath 训练库路径
* @param language 语言字库
* @return
*/
public static String readChar(String path, String dataPath, String language){
        File imageFile = new File(path);
        ITesseract instance = new Tesseract();
        instance.setDatapath(dataPath);
        //英文库识别数字比较准确
        instance.setLanguage(language);
        return getOCRText(instance, imageFile);
    }

    /**
     * 识别图片文件中的文字
* @param instance
* @param imageFile
* @return
*/
private static String getOCRText(ITesseract instance, File imageFile){
        String result = null;
        try {
            result = instance.doOCR(imageFile);
        } catch (TesseractException e) {
            e.printStackTrace();
        }
        return result;
    }

    public static void main(String[] args) {
        /*String path = "src/main/resources/image/text.png";
        System.out.println(readChar(path));*/

        String ch = "src/main/resources/image/ch.png";
        System.out.println(readChar(ch, "src/main/resources", Const.CHI_SIM));
    }

}
注释:中文结果不够准确,需要自己训练字库
具体训练字库,以及完整代码请移步https://github.com/followwwind/javautils

JAVA使用Tess4J进行ocr识别

标签:ews   meta   性能   http   速度   ive   arr   rectangle   自己   

原文:https://www.cnblogs.com/pejsidney/p/9487881.html

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