The application of fractional wavelet transform in image enhancement
Chunhua Guo · International Journal of Computers and Applications · 2019
The fractional wavelet transform is a generalized extension of the wavelet multi-resolution analysis in time-fractional frequency domain. It can characterize signal features in time domain and fractional frequency domain. Based on the multi-resolution analysis of fractional wavelet, the process of decomposition and reconstruction of discrete fractional wavelet transform is derived, and it is extended to two dimensions. According to the characteristic that the subband energy of fractional wavelet transform varies with the order P, a novel image enhancement method is proposed. All the fractional wavelet coefficients at large scale and low resolution are retained, and a nonlinear adaptive gain method is used for the high-resolution subband coefficients. The experimental results show that the performance of this method is better than the traditional wavelet enhancement method both in vision effect and contrast improvement index.