A two crossed Ronchi-gratings quantitative model of Moiré fringe patterns

Moiré fringe technology has been widely used in the fields of measurements due to the good amplification characteristics and imaging characteristics. For the more generic case where the two crossed-gratings have different line spacing and the angle between the gratings is non-zero, the calculation for the Moiré fringe pattern tends to be rather complex. In this paper, a quantitative model of Moiré fringe patterns based on two crossed Ronchi-gratings is deduced. This is further propelled by the fact that the characteristics of Moiré fringe patterns tend to be simplified provided the pitch widths of two crossed-gratings are integral multiples. Numerical simulations and experimental setup have been carried out to ascertain the effectiveness and relevance of the proposed quantitative model. Results indicate that this model is satisfactorily justifiable and can be effectively applied especially when two gratings are integral multiples of each other.