RT Journal Article
T1 Automatic processing in Moiré deflectometry by local fringe direction calculation
A1 Canabal Boutureira, Héctor Alfonso
A1 Quiroga Mellado, Juan Antonio
A1 Bernabéu Martínez, Eusebio
AB An algorithm for accurately extracting the local fringe direction is presented. The algorithm estimates, in the neighborhood of n × n points, the direction of the gradient that points normal to the local fringe direction. The performance of four different derivative kernels is also compared. Since this method is sensitive to noise and variations in background and amplitude, a preprocessing step is used to limit these error sources. The method has been applied to the moiré deflectogram of a spherical and a progressive addition ophthalmic lens, resulting in a map of the refractive power of these lenses. The results are compared with the data obtained with a commercial focimeter. This technique is useful for analyzing the fringe patterns where the fringe direction is variable and must be obtained locally.
PB The Optical Society of America
SN 0003-6935
YR 1998
FD 1998-09-01
LK https://hdl.handle.net/20.500.14352/58796
UL https://hdl.handle.net/20.500.14352/58796
LA eng
DS Docta Complutense
RD 4 abr 2025