Blur Unblurred—A Mini Tutorial
Optical blur from defocus is quite frequently considered as equivalent to low-pass filtering. Yet that belief, although not entirely wrong, is inaccurate. Here, we wish to disentangle the concepts of dioptric blur, caused by myopia or mis-accommodation, from blur due to low-pass filtering when convo...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
SAGE Publishing
2018-04-01
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| Series: | i-Perception |
| Online Access: | https://doi.org/10.1177/2041669518765850 |
| _version_ | 1818841883159298048 |
|---|---|
| author | Hans Strasburger Michael Bach Sven P. Heinrich |
| author_facet | Hans Strasburger Michael Bach Sven P. Heinrich |
| author_sort | Hans Strasburger |
| collection | DOAJ |
| description | Optical blur from defocus is quite frequently considered as equivalent to low-pass filtering. Yet that belief, although not entirely wrong, is inaccurate. Here, we wish to disentangle the concepts of dioptric blur, caused by myopia or mis-accommodation, from blur due to low-pass filtering when convolving with a Gaussian kernel. Perhaps surprisingly—if well known in optometry—the representation of a blur kernel (or point-spread function) for dioptric blur is, to a good approximation and disregarding diffraction, simply a cylinder. Its projection onto the retina is classically referred to as a blur circle , the diameter of which can easily be deduced from a light-ray model. We further give the derivation of the relationship between the blur-disk’s diameter and the extent of blur in diopters, as well as the diameter’s relation to the near or far point, and finally its relationship to visual acuity. |
| first_indexed | 2024-12-19T04:33:09Z |
| format | Article |
| id | doaj.art-ee18add3770f4cc0a3c405e9d6d51bee |
| institution | Directory Open Access Journal |
| issn | 2041-6695 |
| language | English |
| last_indexed | 2024-12-19T04:33:09Z |
| publishDate | 2018-04-01 |
| publisher | SAGE Publishing |
| record_format | Article |
| series | i-Perception |
| spelling | doaj.art-ee18add3770f4cc0a3c405e9d6d51bee2022-12-21T20:35:50ZengSAGE Publishingi-Perception2041-66952018-04-01910.1177/2041669518765850Blur Unblurred—A Mini TutorialHans StrasburgerMichael BachSven P. HeinrichOptical blur from defocus is quite frequently considered as equivalent to low-pass filtering. Yet that belief, although not entirely wrong, is inaccurate. Here, we wish to disentangle the concepts of dioptric blur, caused by myopia or mis-accommodation, from blur due to low-pass filtering when convolving with a Gaussian kernel. Perhaps surprisingly—if well known in optometry—the representation of a blur kernel (or point-spread function) for dioptric blur is, to a good approximation and disregarding diffraction, simply a cylinder. Its projection onto the retina is classically referred to as a blur circle , the diameter of which can easily be deduced from a light-ray model. We further give the derivation of the relationship between the blur-disk’s diameter and the extent of blur in diopters, as well as the diameter’s relation to the near or far point, and finally its relationship to visual acuity.https://doi.org/10.1177/2041669518765850 |
| spellingShingle | Hans Strasburger Michael Bach Sven P. Heinrich Blur Unblurred—A Mini Tutorial i-Perception |
| title | Blur Unblurred—A Mini Tutorial |
| title_full | Blur Unblurred—A Mini Tutorial |
| title_fullStr | Blur Unblurred—A Mini Tutorial |
| title_full_unstemmed | Blur Unblurred—A Mini Tutorial |
| title_short | Blur Unblurred—A Mini Tutorial |
| title_sort | blur unblurred a mini tutorial |
| url | https://doi.org/10.1177/2041669518765850 |
| work_keys_str_mv | AT hansstrasburger blurunblurredaminitutorial AT michaelbach blurunblurredaminitutorial AT svenpheinrich blurunblurredaminitutorial |