27. A ging and the eye’s optics

Charman, W. N.

doi:10.1201/9781315373034-28

Cited by 4 publications

(4 citation statements)

References 116 publications

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“…Therefore, in terms of visual recognition, it is necessary to present a limit that does not feel a decrease in the image quality compared to the image quality at the depth of . Although various methods may be considered for this criterion, the range of aberration due to defocusing in the eye lens may be determined as the DOF range by applying Rayleigh’s quarter-wavelength rule, which is commonly used optically 50 , 51 . In this case, the coefficient in Eq.…”

Section: Resultsmentioning

confidence: 99%

Extended depth of field in augmented reality

Kim

Kwon

Yoon

2023

Sci Rep

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The 3D display device shows an image with depth information. Conventional 3D display devices based on binocular parallax can focus accurately only on the depth of a specific screen. Because the human eye has a narrow depth of field (DOF) under normal circumstances, 3D displays that provide a relatively wide range of virtual depth areas have limitations on the DOF where clear 3D images are seen. To resolve this problem, it is necessary to find the optical conditions to extend the DOF and analyze the phenomena related to it. For this, by using the Rayleigh criterion and the Strehl ratio, a criterion for this extension of the DOF is suggested. A practical optical structure that can effectively extend the DOF is devised using a flat panel display. This optical structure could be applied to AR, VR, and MR in the field of near-eye displays. From the results of this research, the fundamental optical conditions and standards are proposed for 3D displays that will provide 3D images with extended DOF in the future. Furthermore, it is also expected that these conditions and criteria can be applied to optical designs for the required performance in the development of 3D displays in various fields.

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Section: Resultsmentioning

confidence: 99%

Extended depth of field in augmented reality

Kim

Kwon

Yoon

2023

Sci Rep

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“…Certainly, there is a preponderance of transparent nictitating membranes in birds which forage aquatically. Under water, the cornea and nictitating membrane contribute little to refraction of light entering the eye as the cornea is thin and the refractive indices of water and aqueous humour in the anterior chamber of the eye are similar [31]. Birds protect their eyes during sleep and preening by raising the lower eyelids, which are often quite flimsy.…”

Section: Discussionmentioning

confidence: 99%

The Various Ways in Which Birds Blink

Morris,

Parsons

2023

Animals

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There has, to date, been no systematic study of the various ways in which birds blink. Digital video recordings were made, and studied using still frames, of 524 bird species, mainly in zoos but also in the wild. Videos on 106 species from various sites on the internet were studied, some of which we had also videoed, giving a total of 591 (out of a possible 10,000) species from all 43 orders and 125 (out of a possible 249) families. Digital video recordings were also made of 15 (out of a possible 24) species of crocodile. Three types of blink were observed in birds: (1) Nictitating membrane blinks were rapid and brief (phasic) and occurred mainly on head movement. (2) Upper lid blinks were seen in parrots, owls, pigeons and some others. These were also rapid and brief and accompanied nictitating membrane blinks. (3) Lower lid blinks were slow and sustained (tonic) and occurred with drowsiness and preening. Nictitating membrane blinks and lower lid blinks were seen in crocodiles but not upper lid blinks. Globe retraction, where the eyeball is pulled into the orbit of the skull during a blink, was seen in crocodiles but not birds. Phasic blinks remove debris and moisten the cornea, essential for allowing oxygen to diffuse into the cornea, which has no blood supply. Tonic blinks are probably mainly protective. The orders of birds which have upper lid blinking are not closely related and this feature is probably the result of convergent evolution.

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“…The task of quantifying such image changes arises on many occasions. It has been studied extensively to help identify the best lens power in an autonomous refractive procedure, 1,2 ; there is a need for it in specifying the eye's depth of focus, that is, how rapidly the image quality deteriorates with changing object distance, 3 and it is relevant when estimating expected performance with the new kinds of optical corrections that modern optical technology is beginning to make available, 4 often frankly intended to enhance the range of object distances for which some acuity decrement is accepted at the expense of optimal image quality.…”

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confidence: 99%

Objective Measures of Retinal Image Degradation Due to Refractive Corrections

Westheimer

2021

Optom Vis Sci

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SIGNIFICANCE:There is a need for a measure, as simple and yet as informative as possible, to describe objectively the retinal image quality when a patient views targets at various distances through spectacle, contact, or intraocular corrections with optics more elaborate than single vision. PURPOSE:The purposes of this study are to examine the current status of quantitative descriptions of retinal image blur and find optimal characterization of image degradation. METHODS: A variety of indexes of image degradation are computed for a typical eye and polychromatic light, in and out of focus, and as exemplars of sophisticated wave shaping, when the pupil transmission has been modified to a truncated Bessel amplitude function and to a "fractal" phase function. RESULTS: Figures are shown for the optical transfer, point-and edge-spread functions, and Koenig bar and optotype letter blur for the various imaging and defocus conditions, and the relative values of several blur indexes are compared graphically and in a correlation table.CONCLUSIONS: No single index captures the many ways in which the image can deviate from the diffraction-limited ideal. Among the incomplete descriptors of image degradation, the light distribution at a sharp edge stands out as optimally informative and economical, and, when condensed to just two values, one representing central image sharpness and the other outlying light spread, allows for a quick survey of the imaging deficit.

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27. A ging and the eye’s optics

Cited by 4 publications

References 116 publications

Extended depth of field in augmented reality

Extended depth of field in augmented reality

The Various Ways in Which Birds Blink

Objective Measures of Retinal Image Degradation Due to Refractive Corrections

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