Skew and tilt

skew.md

Given an image containing a rotated block of text at an unknown angle, we need to correct the text skew by:

1. Detecting the block of text in the image.
2. Computing the angle of the rotated text.
3. Rotating the image to correct for the skew.

Mat correctSkew()
{
    Mat warpMat = Imgproc.getAffineTransform( new MatOfPoint2f(srcTri), new MatOfPoint2f(dstTri) );
    Mat warpDst = Mat.zeros( src.rows(), src.cols(), src.type() );
    Imgproc.warpAffine( src, warpDst, warpMat, warpDst.size() );
    Point center = new Point(warpDst.cols() / 2, warpDst.rows() / 2);
    double angle = -50.0;
    double scale = 0.6;
    
    // Rotate matrix Opencv Function
    Mat rotMat = ##Imgproc.getRotationMatrix2D( center, angle, scale );
    
    Mat warpRotateDst = new Mat();
    Imgproc.warpAffine( warpDst, warpRotateDst, rotMat, warpDst.size() );
    
    return warpRotateDst;
}