Question

我正在使用Java版Opencv开发OCR软件进行表检测。我能够检测到图像的几乎所有文本边框，但我已经问过＆＃34;圈出＆＃34;字/数字。

对于文本检测，我执行以下操作：

我使用形态学操作检测表格中的水平和垂直线条，并从执行减法的原始Mat图像中删除这些线条（不确定是否是执行此操作的最佳方法）：

    Imgproc.cvtColor(src, gray, Imgproc.COLOR_BGR2GRAY);
    // apply adaptive threshold at the bitwise_not of gray
    Mat bw = new Mat();
    Core.bitwise_not(gray, gray);
    Imgproc.threshold(gray, bw, 0.0, 255.0, Imgproc.THRESH_BINARY | Imgproc.THRESH_OTSU);

    // create the images that will use to extrat the horizontal and vertical lines
    Mat horizontal = bw.clone();
    Mat vertical = bw.clone();

    // Specify size on horizontal axis
    int horizontalSize = horizontal.cols() / 20;
    Mat horizontalStructure = Imgproc.getStructuringElement(Imgproc.MORPH_RECT, new Size(horizontalSize, 1));

    // apply morphology operations
    Imgproc.erode(horizontal, horizontal, horizontalStructure, new Point(-1, -1), 1);
    Imgproc.dilate(horizontal, horizontal, horizontalStructure, new Point(-1, -1), 1);
    // Imgproc.blur(horizontal, horizontal, new Size(3,3));
    Mat kernel = Imgproc.getStructuringElement(Imgproc.MORPH_DILATE, new Size(3, 3));
    Imgproc.dilate(horizontal, horizontal, kernel, new Point(-1, -1), 1);

    // Specify size on vertical axis
    int verticalSize = vertical.rows() / 20;
    Mat verticalStructure = Imgproc.getStructuringElement(Imgproc.MORPH_RECT, new Size(1, verticalSize));

    // apply morphology operations
    Imgproc.erode(vertical, vertical, verticalStructure, new Point(-1, -1), 1);
    Imgproc.dilate(vertical, vertical, verticalStructure, new Point(-1, -1), 1);
    kernel = Imgproc.getStructuringElement(Imgproc.MORPH_DILATE, new Size(3, 3));
    Imgproc.dilate(vertical, vertical, kernel, new Point(-1, -1), 1);

    //Is the correct way to do this?
    // delete lines from binary image
    Core.subtract(bw, horizontal, bw);
    Core.subtract(bw, vertical, bw);

然后使用findContours函数我得到单词边界：

    ArrayList<MatOfPoint> contours = new ArrayList<MatOfPoint>();
    Mat hierarchy = new Mat();
    Imgproc.findContours(bw, contours, hierarchy, Imgproc.RETR_LIST, Imgproc.CHAIN_APPROX_SIMPLE);

中间和最终结果显示在图像中：

Inv binary image with no lines and final result

问题在于无法识别带圈数字，我无法检测并移除表格底部数字周围的圆圈。我尝试过使用 Hough Circles Transform 和fitEllipse方法，结果不佳。尝试通过将椭圆与椭圆相匹配来删除圆圈是最好的方法吗？

有人能建议一个有效的程序来实现这个目标吗？

Opencv检测文本周围的椭圆

0 个答案: