Image enhancement by spatial frequency post-processing of images obtained with pupil filters

The use of apodizing or superresolving filters improves the performance of an optical system in different frequency bands. This improvement can be seen as an increase in the OTF value compared to the OTF for the clear aperture. In this paper we propose a method to enhance the contrast of an image in...

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Autores principales: Iemmi, Claudio César, Ledesma, Silvia Adriana
Publicado: 2016
Materias:
Apodization
Diffraction
Image enhancement
Resolution
Frequency bands
Inverse problems
Inverse transforms
Optical resolving power
Optical systems
Optical transfer function
Apodizations
Apodizing filters
Contrast improvements
Different frequency
High frequency HF
Pass-band filters
Spatial frequency
Transmission filters
Bandpass filters
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00304018_v380_n_p21_Estevez
http://hdl.handle.net/20.500.12110/paper_00304018_v380_n_p21_Estevez
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_00304018_v380_n_p21_Estevez
record_format dspace
spelling paper:paper_00304018_v380_n_p21_Estevez2023-06-08T14:56:07Z Image enhancement by spatial frequency post-processing of images obtained with pupil filters Iemmi, Claudio César Ledesma, Silvia Adriana Apodization Diffraction Image enhancement Resolution Diffraction Frequency bands Image enhancement Inverse problems Inverse transforms Optical resolving power Optical systems Optical transfer function Apodizations Apodizing filters Contrast improvements Different frequency High frequency HF Pass-band filters Spatial frequency Transmission filters Bandpass filters The use of apodizing or superresolving filters improves the performance of an optical system in different frequency bands. This improvement can be seen as an increase in the OTF value compared to the OTF for the clear aperture. In this paper we propose a method to enhance the contrast of an image in both its low and its high frequencies. The method is based on the generation of a synthetic Optical Transfer Function, by multiplexing the OTFs given by the use of different non-uniform transmission filters on the pupil. We propose to capture three images, one obtained with a clear pupil, one obtained with an apodizing filter that enhances the low frequencies and another one taken with a superresolving filter that improves the high frequencies. In the Fourier domain the three spectra are combined by using smoothed passband filters, and then the inverse transform is performed. We show that we can create an enhanced image better than the image obtained with the clear aperture. To evaluate the performance of the method, bar tests (sinusoidal tests) with different frequency content are used. The results show that a contrast improvement in the high and low frequencies is obtained. © 2016 Fil:Iemmi, C. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Ledesma, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2016 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00304018_v380_n_p21_Estevez http://hdl.handle.net/20.500.12110/paper_00304018_v380_n_p21_Estevez
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Apodization
Diffraction
Image enhancement
Resolution
Diffraction
Frequency bands
Image enhancement
Inverse problems
Inverse transforms
Optical resolving power
Optical systems
Optical transfer function
Apodizations
Apodizing filters
Contrast improvements
Different frequency
High frequency HF
Pass-band filters
Spatial frequency
Transmission filters
Bandpass filters
spellingShingle Apodization
Diffraction
Image enhancement
Resolution
Diffraction
Frequency bands
Image enhancement
Inverse problems
Inverse transforms
Optical resolving power
Optical systems
Optical transfer function
Apodizations
Apodizing filters
Contrast improvements
Different frequency
High frequency HF
Pass-band filters
Spatial frequency
Transmission filters
Bandpass filters
Iemmi, Claudio César
Ledesma, Silvia Adriana
Image enhancement by spatial frequency post-processing of images obtained with pupil filters
topic_facet Apodization
Diffraction
Image enhancement
Resolution
Diffraction
Frequency bands
Image enhancement
Inverse problems
Inverse transforms
Optical resolving power
Optical systems
Optical transfer function
Apodizations
Apodizing filters
Contrast improvements
Different frequency
High frequency HF
Pass-band filters
Spatial frequency
Transmission filters
Bandpass filters
description The use of apodizing or superresolving filters improves the performance of an optical system in different frequency bands. This improvement can be seen as an increase in the OTF value compared to the OTF for the clear aperture. In this paper we propose a method to enhance the contrast of an image in both its low and its high frequencies. The method is based on the generation of a synthetic Optical Transfer Function, by multiplexing the OTFs given by the use of different non-uniform transmission filters on the pupil. We propose to capture three images, one obtained with a clear pupil, one obtained with an apodizing filter that enhances the low frequencies and another one taken with a superresolving filter that improves the high frequencies. In the Fourier domain the three spectra are combined by using smoothed passband filters, and then the inverse transform is performed. We show that we can create an enhanced image better than the image obtained with the clear aperture. To evaluate the performance of the method, bar tests (sinusoidal tests) with different frequency content are used. The results show that a contrast improvement in the high and low frequencies is obtained. © 2016
author Iemmi, Claudio César
Ledesma, Silvia Adriana
author_facet Iemmi, Claudio César
Ledesma, Silvia Adriana
author_sort Iemmi, Claudio César
title Image enhancement by spatial frequency post-processing of images obtained with pupil filters
title_short Image enhancement by spatial frequency post-processing of images obtained with pupil filters
title_full Image enhancement by spatial frequency post-processing of images obtained with pupil filters
title_fullStr Image enhancement by spatial frequency post-processing of images obtained with pupil filters
title_full_unstemmed Image enhancement by spatial frequency post-processing of images obtained with pupil filters
title_sort image enhancement by spatial frequency post-processing of images obtained with pupil filters
publishDate 2016
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00304018_v380_n_p21_Estevez
http://hdl.handle.net/20.500.12110/paper_00304018_v380_n_p21_Estevez
work_keys_str_mv AT iemmiclaudiocesar imageenhancementbyspatialfrequencypostprocessingofimagesobtainedwithpupilfilters
AT ledesmasilviaadriana imageenhancementbyspatialfrequencypostprocessingofimagesobtainedwithpupilfilters
_version_ 1768542975864864768

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