Title: Generalised homomorphic and root filtering in 2D-nonseparable discrete linear canonical transform domains in the image enhancement applications

Authors: Shobha Sharma; Tarun Varma

Addresses: Department of Electronics and Communication, Malaviya National Institute of Technology (MNIT), JLN Marg, Jaipur, India ' Department of Electronics and Communication, Malaviya National Institute of Technology (MNIT), JLN Marg, Jaipur, India

Abstract: In this paper, the generalised homomorphic filtering (HF) and root filtering (RF) techniques are extended to 2D-nonseparable discrete linear canonical transform (2D-NsDLCT) domains in the low light image enhancement applications. The objective is to improve the visual appearance for the benefit of further processing. The input image is first transformed into 2D-NsDLCT domains in the proposed methodology, and then HF or RF is applied to it. The filtered image is inverse transformed to the spatial domain. The advantage of the proposed technique is based on the fact that the 2D-NsDLCT domains provide many free parameters that can be varied to improve the visual quality of the given images. We have compared the simulation results of the proposed methods with the special cases of 2D-NsDLCT and state-of-the-art methods. The computed quality metrics reveal that the output images of the proposed methods have better quality than the competing techniques.

Keywords: NsLCT; homomorphic filtering; root filtering; image enhancement.

DOI: 10.1504/IJCVR.2023.129437

International Journal of Computational Vision and Robotics, 2023 Vol.13 No.2, pp.152 - 173

Received: 31 Jul 2021
Accepted: 05 Oct 2021
Published online: 09 Mar 2023 *

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