class function DetectSkewAngle(points: CPointList; width: integer; height: integer): float; overload;

class function DetectSkewAngle(bitmap: BitmapBW): float; overload; This method detects a skew angle of the given points using Hough transform. Angle detection range is restricted by -45..45 degrees. 

Returns estimated skew angle in radians. 

Hough transform