Improved moment invariants for shape discrimination

Moment invariants have been frequently used as features for shape recognition. They are computed based on the information provided by both the shape boundary and its interior region. Although several fast algorithms for computing traditional moment invariants have been proposed, none has ever shown the theoretical results of moment invariants computed based on the shape boundary only. This paper proposes improved moment invariants computed using the shape boundary only, which tremendously reduces computations. The new moment invariants, called improved moment invariants are mathematically proved to be invariant to scaling, translation, and rotation. Graphical plots of the first two improved moment invariants for six country maps and four industrial tools using improved moment invariants are also given. The results suggest that improved moment invariants can be used as effective features for shape discrimination or recognition. Improved moment invariants Traditional moment invariants Shape feature extraction Shape recognition