Square to hexagonal lattice conversion in the frequency domain

Currently, hexagonal image processing is mainly based on simulated data generated by square lattice conversions. For the evaluation of the conversion quality, this paper presents a method for ideal square to hexagonal lattice conversion. Based on the square lattice discrete-time Fourier transform (DTFT), the method first determines the values of the hexagonal discrete Fourier transform (HDFT), and performs the inverse HDFT to obtain the ideal conversion. This method provides a benchmark for evaluating other practical conversions and such evaluation is presented in this paper.