The assessment of phase only filters in imaging systems by the classical optical merit functions

Spatial light modulators (SLM) have found a wide range of applications in many fields of optical imaging and measurement systems. We implement different phase only filters in the pupil plane of an imaging system. The phase only filter is divided in five equally spaced annuli. Each annulus has a diff...

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Guardado en:
Detalles Bibliográficos
Publicado: 2008
Materias:
Diffractive optics
Optical imaging theory
Optical merit functions
Optical system design
Photon management
Spatial light modulators
Computer graphics
Digital arithmetic
Digital image storage
Functions
Image processing
Image quality
Imaging systems
Imaging techniques
Lead
Light modulation
Light modulators
Liquid membranes
Modulation
Optical data processing
Optical filters
Optical systems
Optical transfer function
Optoelectronic devices
Transfer functions
Wave filters
Alternating phase
Digital image processing
Image intensities
Image planes
Line-spread function (LSF)
Measurement systems
Merit functions
Modulation Transfer Function (MTF)
Optical (PET) (OPET)
Optical imaging
Phase transmission
Phase-only filtering
Point Spread Function (PSF)
Pupil planes
Side lobes
Spatial light modulators (SLM)
Wide-range
Three dimensional
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_0277786X_v7000_n_p_Hild
http://hdl.handle.net/20.500.12110/paper_0277786X_v7000_n_p_Hild
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
Descripción
Sumario:Spatial light modulators (SLM) have found a wide range of applications in many fields of optical imaging and measurement systems. We implement different phase only filters in the pupil plane of an imaging system. The phase only filter is divided in five equally spaced annuli. Each annulus has a different phase transmission and inside each annulus the phase is constant. We analyse first the influence of linear decreasing or increasing phase, second we use one phase annulus with a phase shift of π in different positions over the pupil and finally an alternating phase between 0 and π over the pupil. Merit functions of the different filters are calculated. The radial and axial point spread function (PSF) or the 3D line spread function show that in some cases these phase only filters will shift the best image plane. The experimental results show the close correlation to the calculated shift of the best image plane. The strong side lobes that appear in the merit functions lead to the conclusion that the image quality will be influenced as well. This can be confirmed by the calculation and the measurement of the image intensity. So in order to get more information about the expected image it is necessary to study the 3D modulation transfer function (MTF). With the MTF one can see that the contrast decreases for the image obtained with each filter in comparison with the image obtained with the clear pupil. The conclusion of our work is, that it is necessary to study the influence of all merit functions in order to design an optimum filter for a given application.

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