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Riesz-Laplace Wavelet Transform and PCNN Based Image Fusion

Sun Shuifa, Tang Yongheng, Mei Zhoujunshen, Yang Min, Tang Tinglong, Wu Yirong

Machine Graphics and Vision

2023

Vol. 32, No. 1

73--84

Important information perceived by human vision comes from the low-level features of the image, which can be extracted by the Riesz transform. In this study, we propose a Riesz transform based approach to image fusion. The image to be fused is first decomposed using the Riesz transform. Then the image sequence obtained in the Riesz transform domain is subjected to the Laplacian wavelet transform based on the fractional Laplacian operators and the multi-harmonic splines. After Laplacian wavelet transform, the image representations have directional and multi-resolution characteristics. Finally, image fusion is performed, leveraging Riesz-Laplace wavelet analysis and the global coupling characteristics of pulse coupled neural network (PCNN). The proposed approach has been tested in several application scenarios, such as multi-focus imaging, medical imaging, remote sensing full-color imaging, and multi-spectral imaging. Compared with conventional methods, the proposed approach demonstrates superior performance on visual effects, contrast, clarity, and the overall efficiency.

Inequalities for second-order Riesz transforms associated with Bessel expansions

Osękowski Adam

Bulletin of the Polish Academy of Sciences. Mathematics

2020

Vol. 68, no. 1

75--88

The paper contains the proofs of Lp, logarithmic and weak-type estimates for the second-order Riesz transforms arising in the context of multidimensional Bessel expansions. Using a novel probabilistic approach, which rests on martingale methods and the representation of Riesz transforms via associated Bessel-heat processes, we show that these estimates hold with constants independent of the dimension.

Seminormal systems of operators in Clifford environments

Mircea M.

Opuscula Mathematica

2017

Vol. 37, no. 1

81--107

The primary goal of our article is to implement some standard spin geometry techniques related to the study of Dirac and Laplace operators on Dirac vector bundles into the multidimensional theory of Hilbert space operators. The transition from spin geometry to operator theory relies on the use of Clifford environments, which essentially are Clifford algebra augmentations of unital complex C*-algebras that enable one to set up counterparts of the geometric Bochner-Weitzenbock and Bochner-Kodaira-Nakano curvature identities for systems of elements of a C*-algebra. The so derived self-commutator identities in conjunction with Bochner’s method provide a natural motivation for the definitions of several types of seminormal systems of operators. As part of their study, we single out certain spectral properties, introduce and analyze a singular integral model that involves Riesz transforms, and prove some self-commutator inequalities.