In this paper, exact behavior of Complex Zernike Moments is analyzed. Zernike Moments contain two parameters: magnitude and orientation. In literature, mostly magnitude is considered to recognize the shape, because magnitude is orientation invariant. On the other hand, orientation of an image has its own significance in case of sign language. This work is dedicated to the study of the capability of Zernike Moments to recognize shape and orientation of Indian Sign Language gestures.
Database of total 720 images of five signs (C, I, L, T, V) is used here. Test sets are designed such that they are shape specific, orientation variant and orientation invariant. Experiments are performed on these test sets for magnitude, phase and their combination. High accuracy is achieved even at lower order of Zernike Moments when both magnitude and phase are used as a feature set.