function Out = RunLengthF(I)
% Input:     - I: A 2D image
%
%
% Output:    - Out: A (1x44) vector containing 44 metrics calculated based
%              on run length of image structures
%
% Note: This function calls grayrlmatrix.m and grayrlprops.m, which are
%       also included in ImFEATbox and have been implemented by:
%       Xunkai Wei <xunkai.wei@gmail.com>, Beijing Aeronautical Technology 
%       Research Center
%
% ************************************************************************
% Implemented for MRI feature extraction by the Department of Diagnostic 
% and Interventional Radiology, University Hospital of Tuebingen, Germany 
% and the Institute of Signal Processing and System Theory University of 
% Stuttgart, Germany. Last modified: December 2016
%
% This implementation is part of ImFEATbox, a toolbox for image feature
% extraction and analysis. Available online at:
% https://github.com/annikaliebgott/ImFEATbox
%
% Contact: annika.liebgott@iss.uni-stuttgart.de
% ************************************************************************

% grayrlmatrix.m can not process complex values
I = double(real(I)); 

[GLRLMS,~] = grayrlmatrix(I,'NumLevels',255,'G',[min(I(:)) max(I(:))]);
VectorDegree = grayrlprops(GLRLMS);
Out(1,:) = [VectorDegree(1,:) VectorDegree(2,:) VectorDegree(3,:) VectorDegree(4,:)];

end