Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1982-8-14
pubmed:abstractText
With the increasing popularity of periodic gratings in vision research, the effects of ocular defocus, such as spurious resolution and the presence of more than one maximum in the contrast - defocus level function, are very important. Optical transfer function theory is used to develop graphs and formulae that can be used to predict the presence of spurious resolution for given levels of defocus and spatial frequency in aberration-free optical system. Geometrical optical approximations are used extensively, as these lead to very simple formulae. These general equations, applying to any optical system, are extended to the particular case of ocular defocus. Formulae are presented that can be used to predict the presence of spurious resolution, in terms of such variables as pupil size and longitudinal focus error. Conditions for the observation of spuriously resolved gratings are also discussed. An example is presented for observing spurious resolution and contrast reversal and this example can be presented as a "pseudo" visual illusion.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:issn
0275-5408
pubmed:author
pubmed:issnType
Print
pubmed:volume
2
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5-23
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1982
pubmed:articleTitle
Ocular defocus, spurious resolution and contrast reversal.
pubmed:publicationType
Journal Article