1. A method for describing image outlines ( 100 ), the method comprising: receiving a parametric equation of a closed planar curve ( 101 ); choosing nodes on the closed planar curve with equal intervals ( 102 ); generating a continuous scale space of the nodes on the closed planar curve by successively convolving the closed planar curve with a Gaussian filter and down-sampling it after each octave ( 103 ); calculating a plurality of orientation vectors and an orientation angle values for each sampled point at each interval of each octave ( 104 ); creating an orientation scale space (OSS) which is a matrix obtained from stacking each orientation angle value on top of each other ( 105 ); and representing the outline with a. descriptor including all the orientation vectors and their respective parameters position and scale ( 106 ).