Hand Gesture Shape Descriptor Based on Energy-Ratio and Normalized Fourier Transform Coefficients

The hand gesture shape is the most remarkable feature for gesture recognition system. Since hand gesture is diversity, polysemy, complex deformation and spatio-temporal difference, the hand gesture shape descriptor is a challenging problem for gesture recognition. This paper presents a hand gesture shape describing method based on energy-ratio and normalized Fourier descriptors. Firstly, the hand gesture contour of the input image is extracted by YCb'Cr' ellipse skin color model. Secondly, the Fourier coefficients of the contour are calculated to transform the point sequence of the contour to frequency domain. Then the Fourier coefficients are normalized to meet the rotation, translation, scaling and curve origin point invariance. Finally, the items of normalized Fourier coefficients are selected by calculating energy-ratio information as the hand shape descriptors. For validating the shape descriptors performance, the hand gestures 1-10 are recognized with the template matching method and the shape descriptor method, respectively. The experiment results show that the method can well describe the hand shape information and are higher recognition rate.