Robust detectors of rotationally symmetric shapes based on novel semi-shape signatures

•Solid theoretical foundation of a novel semi-shape concept for analyzing the rotationally symmetric attributes of a shape.•Two new projection-based signatures of a shape based on the correlation between its semi-shapes.•A meaningful measure for semi-shape profiles to determine a perfect level of rotational symmetry.•Robust detectors for rotationally symmetric shapes based on LIPs/Rs-signature correspondingly.•A novel dataset, named HCMUTE-RotaShape, including single/compound shapes with challenging rotation properties.•Comprehensive evaluations have verified that the proposed detectors executed well in comparison with state of the art.