2024-03-28T23:00:38Zhttp://diposit.ub.edu/dspace-oai/requestoai:diposit.ub.edu:2445/1047982024-03-12T17:02:13Zcom_2445_8480com_2445_7181col_2445_104796
Is wavefront coding an alternative to adaptive optics for retinal imaging?
Acosta, Eva
Arines, J.
Almaguer-Gómez, C.
Bosch i Puig, Salvador
Vallmitjana i Rico, Santiago
Òptica
Retina
Processament d'imatges
Optics
Retina
Image processing
In this work we explore the use of the wavefront coding technique for obtaining high resolution images of the retina of human eyes. The numerical analysis pretends to show the robustness of the technique under changes in pupil diameter and wavefront shape including intersubject and intrasubject variability, using always the same restoration filter or image decoder. The results show that it is possible to obtain high resolution images under different ocular aberrations and pupil diameters with the same decoder, opening the possibility of real time high resolution images with this low-cost and robust technique.
2016-12-16T12:01:40Z
2016-12-16T12:01:40Z
2016-07
info:eu-repo/semantics/conferenceObject
http://hdl.handle.net/2445/104798
eng
Comunicació presentada a: 15th Workshop on Informatio Optics (WIO). Universitat de Barcelona. Barcelona, 15-15 July 2016
(c) Acosta, E. et al., 2016
info:eu-repo/semantics/openAccess
3 p.
application/pdf
Comunicacions a congressos (Física Aplicada)
oai:diposit.ub.edu:2445/1195762024-03-12T17:02:13Zcom_2445_8480com_2445_7181col_2445_104796
Characterization of VGA liquid crystal panels with partial phase-only modulation: application to pattern recognition
Vallmitjana i Rico, Santiago
Labastida i Juan, Ignasi, 1970-
Martín Badosa, Estela
Carnicer González, Arturo
Juvells Prades, Ignacio
Cristalls líquids
Òptica
Modulació (Electrònica)
Liquid crystals
Optics
Modulation (Electronics)
The inclusion of optoelectronic displays has enabled optical correlators to improve radically and maintain the competitive edge of optical processors among information processing fields. In this work, an optical correlator has been implemented by using two VGA liquid crystal displays as spatial light modulators, both at the input and Fourier planes. These devices have been removed from a commercial videoprojector and have been characterized in order to operate in different configurations. This characterization is based on an interferometric procedure which includes amplitude and phase modulation measurements. For a phase-only modulation we have compared the use of linearly and elliptically polarized light. In this latter case we have found an operating curve with phase-only modulation which takes values from 0 to π radians. This is a limitation when a pure phase filter is required as in data security and encryption, in wavelet-based systems, and in optical pattern recognition, among others. An application in this latter field is presented in our work as a solution to overcome this limited phase depth. We propose a modification of the classical phase-only filter based on the use of the absolute value of the phase. Experimental correlation results using the optical setup and the modified filter have been obtained.
2018-02-05T11:19:09Z
2018-02-05T11:19:09Z
1999
info:eu-repo/semantics/conferenceObject
http://hdl.handle.net/2445/119576
eng
Reproducció del document publicat a http://dx.doi.org/10.1117/12.365915
Congrès: Euro-American Workshop on Optoelectronic Information Processing, 1999, Colmar, France
Proc. of SPIE Vol. 10296 (Vol. CR74), 1029605 (1999) 2017
http://dx.doi.org/10.1117/12.365915
(c) SPIE, 2017
info:eu-repo/semantics/openAccess
21 p.
application/pdf
SPIE
Comunicacions a congressos (Física Aplicada)