Package com.itextpdf.pdfocr.onnx.util

Class OpenCvUtil

java.lang.Object
com.itextpdf.pdfocr.onnx.util.OpenCvUtil
public final class OpenCvUtil extends Object
Static class with OpenCV utility functions.

  • Method Summary

    Modifier and Type
    Method
    Description
    static org.bytedeco.opencv.opencv_core.Mat
    binarizeMdArray(FloatBufferMdArray hwMdArray, float threshold)
    Takes a two-dimensional MD-array and returns a binarized version of it as an OpenCV Mat.
    static void
    fillPolyAtOffset(org.bytedeco.opencv.opencv_core.Mat bitmap, org.bytedeco.opencv.opencv_core.Mat poly, org.bytedeco.opencv.opencv_core.Scalar color, int xOffset, int yOffset)
    Fill the polygon on the bitmap at a specific offset.
    static org.bytedeco.opencv.opencv_core.Mat
    minAreaRectBoxPoints(org.bytedeco.opencv.opencv_core.Mat points)
    Equivalent to calling OpenCV minAreaRect, followed by boxPoints, but with resource handling taken care of.
    static org.bytedeco.opencv.opencv_core.Mat
    minAreaRectBoxPoly(org.bytedeco.opencv.opencv_core.Mat points)
    Creates an OpenCV polygon, based on the results of a minAreaRectBoxPoints(points) call, but with resource handling taken care of.
    static org.bytedeco.opencv.opencv_core.RotatedRect
    normalizedMinAreaRect(org.bytedeco.opencv.opencv_core.Mat points)
    OpenCV minAreaRect, but returns the normalized rectangle immediately.
    static org.bytedeco.opencv.opencv_core.RotatedRect
    normalizeRotatedRect(org.bytedeco.opencv.opencv_core.RotatedRect rect)
    Normalizes RotatedRect, so that its angle is in the [-45; 45) range.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • binarizeMdArray

      public static org.bytedeco.opencv.opencv_core.Mat binarizeMdArray (FloatBufferMdArray hwMdArray, float threshold)
      Takes a two-dimensional MD-array and returns a binarized version of it as an OpenCV Mat.
      Parameters:
      hwMdArray - MD-array to binarize
      threshold - Threshold for a value to be 0xFF instead of 0x00
      Returns:
      binarized version of the MD-array as an OpenCV Mat

    • normalizedMinAreaRect

      public static org.bytedeco.opencv.opencv_core.RotatedRect normalizedMinAreaRect (org.bytedeco.opencv.opencv_core.Mat points)
      OpenCV minAreaRect, but returns the normalized rectangle immediately. Equivalent to normalizeRotatedRect(opencv_imgproc.minAreaRect(x)).
      Parameters:
      points - vector of 2D points
      Returns:
      normalized min area rect

    • normalizeRotatedRect

      public static org.bytedeco.opencv.opencv_core.RotatedRect normalizeRotatedRect (org.bytedeco.opencv.opencv_core.RotatedRect rect)
      Normalizes RotatedRect, so that its angle is in the [-45; 45) range.

      We want our boxes to have the point order, so that it matches input image orientation. Otherwise, the orientation detection model will get a different box, which is already pre-rotated in some way. Here we will alter the rectangle, so that points would output the expected order.

      This will make box have points in the following order, relative to the page: BL, TL, TR, BR. Bottom as in bottom of the image, not the lowest Y coordinate.

      Parameters:
      rect - RotatedRect to normalize
      Returns:
      normalized RotatedRect

    • minAreaRectBoxPoints

      public static org.bytedeco.opencv.opencv_core.Mat minAreaRectBoxPoints (org.bytedeco.opencv.opencv_core.Mat points)
      Equivalent to calling OpenCV minAreaRect, followed by boxPoints, but with resource handling taken care of.
      Parameters:
      points - points to get the rectangle for
      Returns:
      min area rectangle points

    • minAreaRectBoxPoly

      public static org.bytedeco.opencv.opencv_core.Mat minAreaRectBoxPoly (org.bytedeco.opencv.opencv_core.Mat points)
      Creates an OpenCV polygon, based on the results of a minAreaRectBoxPoints(points) call, but with resource handling taken care of.
      Parameters:
      points - points to get the rectangle for
      Returns:
      min area rectangle polygon

    • fillPolyAtOffset

      public static void fillPolyAtOffset (org.bytedeco.opencv.opencv_core.Mat bitmap, org.bytedeco.opencv.opencv_core.Mat poly, org.bytedeco.opencv.opencv_core.Scalar color, int xOffset, int yOffset)
      Fill the polygon on the bitmap at a specific offset.
      Parameters:
      bitmap - bitmap to fill the polygon on
      poly - polygon to fill
      color - color to fill the polygon with
      xOffset - x offset for the polygon
      yOffset - y offset for the polygon