We present an algorithm that uses a square grid in a Ronchi test. We assume that the point coordinates of this pattern (termed a bironchigram) are affected by Gaussian errors. To calculate the optical path difference, we apply only one nonlinear least-squares fit to the dot coordinates. The relevant equations are deduced, and experimental results are shown.
© 2001 Optical Society of America
Alberto Cordero-Dávila, Juan Manuel Nuũez-Alfonso, Esteban Luna-Aguilar, and Carlos Ignacio Robledo-Sánchez, "Only One Fitting for Bironchigrams," Appl. Opt. 40, 5600-5609 (2001)