Paired Directional Transform Based Methods of Image Enhancement

摘要

In this paper, an effective realization of the α-rooting method of image enhancement by splitting-signals is proposed. The splitting-signals completely determine the image and split its spectrum by disjoint subsets of frequencies. Image enhancement is reduced to processing separate splitting-signals. We focus on processing only one specified splitting-signal, to achieve effective image enhancement that in many cases exceeds the enhancement by known α-rooting and wavelet methods. An effective realization of enhancement of image (N x N) is achieved by using one coefficient, instead of N/2 such coefficients for splitting-signals in the split α-rooting and N x N in traditional α-rooting. The proposed method does not require Fourier transforms, its realization is performed with N multiplications. The processing of the splitting-signal leads to the change of the image along the parallel lines by N different values, which leads to the concept of directional images and their application in enhancing the image along directions. A novel method of combining paired transform (pre-step of SMEME (spectral spatial maximum exclusive mean) filter) by wavelet transforms is proposed. While denoising directional clutters, the most corrupted splitting-signal is estimated and found, depending on the angle of long-waves.