System and Method for Identifying Scale Invariant Features of Object Outlines on Images

A method for identifying scale invariant features of image outlines (100) characterized by the steps of;

• 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 curve by successively convolving the planar curve with a Gaussian filter and down-sampling it after each octave (103),
• calculating a value representing the amount of curvature at that point for every node on the closed curve for every scale in every octave (104),
• finding curvature differences between plurality of adjacent scales and forming curvature difference groups (105),
• comparing each curvature difference value with curvature differences belonging to the same and adjacent groups;
• and choosing the nodes with a minimum or maximum curvature difference as feature points (106),
• representing the outline with a descriptor as radial arrays in which radial distance from the center represent the scale value of difference groups, rotation around this center represents the outline curve parameter and the value at each point represents the feature orientation and the radial array is encoded on a two dimensional color image and the two dimensional vectors representing the feature's orientations are encoded with the color of the placed point (107).