A novel approach for developing symmetry-based shape representations is presented. Annular operators are used to identify symmetric relationships existing between sets of edge elements. Operators are applied at multiple scales to edge data which has been extracted at multiple scales from a grey level image. Symmetric structures make it possible to identify where objects are positioned within an image, and may be used as a basis for constructing course descriptors for the projected shape of the objects in the scene. The advantages of this method over previous ones are: (1) it can be applied directly to images with no prior segmentation of objects from ground, (2) it allows for the isolation and interpretation of image structure based upon scale, and (3) it is an entirely parallel process. Preliminary results are demonstrated for two grey-level images.
Michael F. Kelly,
Martin D. Levine,
"Analysis of shape using annular symmetry operators", Proc. SPIE 2239, Visual Information Processing III, (24 June 1994); doi: 10.1117/12.179276; https://doi.org/10.1117/12.179276