Poisson inequality for the Radon transform is a key tool in signal analysis and processing. An analogue of the Hardy-Littlewood-Poisson inequality for the Radon transform of infinitely differentiable functions is proved. The result is related to a paper of Luan and Vieira (J. Inequal. Appl. 2017:12, 2017) and to a previous paper by Yang and Ren (Proc. Indian Acad. Sci. Math. Sci. 124(2):175-178, 2014).
Keywords: Infinitely differentiable functions; Poisson inequality; Radon transform.