Tesis doctoral de Esther Oteo Lozano
This phd dissertation describes a new method for misalignment calculation in optical systems. the need to quantify the misalignments in optical systems arise from a project developed at the center for sensors, instruments and systems of the technical university of catalonia under private contract. This project required to know the misalignment status of two cylindrical lenses of a cinema camera anamorphic attachment. we studied the possibility of calculating the state of misalignment from the analysis of the psf on axis and field positions of the optical system, obtaining a shape behavior pattern by simulation, developing the calculation from the position and shape of the psf. However, beyond the project, we saw the possibility of performing the calculation for any optical system if instead of the psf we used the wavefront at the output of the optical system. This thesis includes the development and study of this last method. the method developed in the doctoral thesis establishes a relationship between the wavefront at the output of the optical system and the misalignment values of the system elements. This relationship is modeled by a transformation function with internal parameters values that are unique for each optical system. The transformation function, whose internal parameters are adjusted by simulation, is used to calculate the misalignments of the elements from the values of the zernike coefficients representing wavefront. throughout the development of the thesis we have studied three different transformation functions that have been set for the particular case of a cooke triplet with a misaligned lens. The transformation functions studied are: a system of linear equations, a system of cubic equations and an artificial neural network. Special attention has been paid to the latter for its great calculation potential. each transformation function has been applied by simulation to calculate the misalignment values of tilt and decenter for 500 randomly generated misalignment states for the second lens of the cooke triplet. To evaluate the result, the calculated value is compared with the expected value. transformation functions based in linear equations system and third degree system have not provided satisfactory results for the case when of both tilt and decenter misalignments are present. However, satisfactory results have been obtained for the case of having only tilt or only decenter values. applying the method by the transformation function based in neural networks, we have obtained satisfactory results, with a theoretical error below 0.03% of the maximum misalignment value, when the lens has both tilt and decenter misalignments. afterwards, the method has been generalized for calculating misalignments for more than one element, using the wavefront in field and axis positions for the same optical system. We have studied the behavior of the zernike coefficients values against misalignments, leading to the conclusion that in order to solve the large number of misalignment variables for the two lenses, it is needed to expand the number of wavefronts. So the wavefronts for different field positions have been obtained by simulation and hence the corresponding zernike coefficients. The transformation function based in neural networks has been applied with the on-axis and field zernike coefficients for the misalignments calculation of the two lenses, obtaining theoretical errors below 0.16% of the maximum misalignment value for the two lenses of the cooke triplet.
Datos académicos de la tesis doctoral «Método de cálculo de desalineamientos en sistemas ópticos. aplicación mediante redes neuronales.«
- Título de la tesis: Método de cálculo de desalineamientos en sistemas ópticos. aplicación mediante redes neuronales.
- Autor: Esther Oteo Lozano
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 27/09/2013
Dirección y tribunal
- Director de la tesis
- Josep Arasa Martí
- Tribunal
- Presidente del tribunal: jaume Pujol ramo
- Santiago Miguel Olaizola izquierdo (vocal)
- (vocal)
- (vocal)