2.2.1. The finite radon transform The FRAT was first introduced in Ref. [29] as the finite analogue of integration in the continuous Radon transform (CRT), with origins in the field of combinatorics. The mathematical representation of an injective form of the FRAT to ensure invertibility when applied on finite Euclidian planes has been presented in Ref. [30]. It is worth mentioning that the FRAT is not a discredited version of the RT, but a discrete finite version. Consider a cyclic group Zp denoted by Zp=(0,1,...,p−1) such that p is a prime number. Let the finite grid Z2 p be defined as the Cartesian product of Zp ×Zp. This finite grid has (p+1) non-trivial subgroups, given