Zuhair Ahmed, Diako Mardanbegi, Dan Witzner Hansen · IT University Of Copenhagen (IT University of Copenhagen) · 2016
We investigate the gaze estimation error induced by pupil size changes using simulated data. We investigate the influence of pupil diameter changes on estimated gaze point error obtained by two gaze estimation models. Simulation data show that at wider viewing angles and at small eye-camera distances, error increases with increasing pupil sizes. The maximum error recorded for refracted pupil images is 2.4° of visual angle and 1.5° for non-refracted pupil projections.
Cited by 3Open access
Massoumian, Farnaz · OpenGrey (Institut de l'Information Scientifique et Technique) · 2003
Cited by 0
Joseph C. Stevens, Lawrence E. Marks · Perception & Psychophysics · 1972
Cited by 5Open access
Kyulim Kim, Jeongsoo Kim, Seungri Song et al. · Optics Express · 2022
Adversarial attacks inject imperceptible noise to images to deteriorate the performance of deep image classification models. However, most of the existing studies consider attacks in the digital (pixel) domain where an image acquired by an image sensor with sampling and quantization is recorded. This paper, for the first time, introduces a scheme for optical adversarial attack, which physically alters the light field information arriving at the image sensor so that the classification model yields misclassification. We modulate the phase of the light in the Fourier domain using a spatial light modulator placed in the photographic system. The operative parameters of the modulator for adversarial attack are obtained by gradient-based optimization to maximize cross-entropy and minimize distortion. Experiments based on both simulation and a real optical system demonstrate the feasibility of the proposed optical attack. We show that our attack can conceal perturbations in the image more effectively than the existing pixel-domain attack. It is also verified that the proposed attack is completely different from common optical aberrations such as spherical aberration, defocus, and astigmatism in terms of both perturbation patterns and classification results.
Cited by 6Open access
P. Shailaja, D S Naga Malleswara Rao, Shan Rao · IOSR Journal of Applied Physics · 2024
The point spread function of a complex three-zone pupil function is analyzed in the presence of primary spherical aberration and defocus. The second zone is phase-shifted by -π/5, and the third zone by +π/7. Apodization is applied using three filters: a Bartlett amplitude filter for the inner zone, a shaded amplitude filter for the second zone, and a Hanning amplitude filter for the third zone. The primary goal is to enhance the central maximum's intensity, eliminate side lobes, and reduce the radius of the first dark ring. A notable increase in the central maximum occurs when the apodization parameter is set to β = 1.0, and minimized the first dark ring's radius under high spherical aberration and defocus
Cited by 0Open access
Matthew R. Foreman, Claudiu Giusca, Péter Török et al. · Journal of Microscopy · 2013
This work reports on the retrieval of the pupil function and coherent transfer function of a coherent reflection type confocal microscope from simulated measurements of the intensity point spread function. Two phase retrieval algorithms are presented in this vein, which incorporate the multiple pupil dependence of image formation in confocal microscopy. Verification of the algorithms follows by numerical simulations.
Cited by 13
Tatsuto Takeuchi (348602), Théodore Puntous (348603), Anup Tuladhar (348604) et al. · Figshare · 2015
<p>(A) Each function represents the averaged pupil diameter of 12 subjects during the conduction of the visual conjunction search task. The data in each trial was normalized relative to the pupil size during the cross fixation period immediately preceding the trial. Different functions denote the different training day: 1<sup>st</sup>, 3<sup>rd</sup>, 5<sup>th</sup>, and 10<sup>th</sup> day, respectively. (B) Each function represents the averaged pupil diameter of 12 subjects conducting the passive viewing task. In passive condition subjects observed the visual search display, but no task was imposed. The data in each trial was normalized relative to the pupil size during the cross fixation period immediately preceding the trial. Different functions denote the different experimental day: 1<sup>st</sup>, 3<sup>rd</sup>, 5<sup>th</sup>, and 10<sup>th</sup> day, respectively.</p>
Cited by 0Open access
José A. Díaz, Rafael Navarro · Optik · 2023
We have studied several pupil sampling patterns for calculating the optical transfer function corresponding to actual non-diffraction limited optical imaging systems, in the low range of spatial frequencies, i.e., where the geometric approach is valid, by means of the Fourier Transform of the spot diagram. Then, we have compared the diffraction and the geometric optical transfer functions to ascertain if there is a sampling pattern that accurately calculates the latter within a 5% of difference, and having less number of sampling points. The results show that, overall, the non redundant spiral pupil sampling provides the best choice. This could be valuable when optimizing or characterizing optical imaging systems in the non-diffraction limited range by harnessing raytracing.
Cited by 3Open access
Bei Zhang · Optics & Laser Technology · 2020
Cited by 1
Lisa M. Fenk (358108), Karin Heidlmayr (358109), Philipp Lindner (358110) et al. · Figshare · 2015
<p>(A) The mean pupil diameters of the PM and AM eyes for a 7-month-old spider as a function of the time after ecdysis. The data were fitted using <i>d</i> = <i>d<sub>f</sub></i> –<i>a</i>/(1+exp((<i>t</i>–<i>t<sub>0</sub></i>)/<i>b</i>)), where <i>d</i> is the pupil diameter and <i>d<sub>f</sub></i> is its asymptotic value for large times <i>t</i>. PM eyes (r<sup>2</sup> = 0.9993): <i>d<sub>f</sub></i> = 817 µm, <i>a</i> = 600 µm, <i>t<sub>0</sub></i> = 32 h, <i>b</i> = 69 h. AM eyes (r<sup>2</sup> = 0.9997): <i>d<sub>f</sub></i> = 626 µm, <i>a</i> = 400 µm, <i>t<sub>0</sub></i> = 61 h, <i>b</i> = 60 h. (B) The pupil-to-lens ratios of the PM eyes of <i>Cupiennius salei</i>, for three different age groups as a function of the time after ecdysis.</p>
Cited by 0Open access
Tom N. Cornsweet · Noninvasive Assessment of the Visual System · 1991
A large proportion of pathologies that affect the retina and visual pathways reduce a patient's sensitivity to light in one eye relative to the other. The swinging flashlight test, first described by Levatin (Arch. Ophthal. 62:768,1959) is a clinically useful way to detect such imbalances. The examiner shines a flashlight into one eye for a few seconds, then shifts abruptly to the other for a few seconds, and continues swinging back and forth while watching whichever eye is being illuminated. As reported by Levatin, when this test is performed on a normal visual system the pupils show little or no reaction because signals from each retina drive both pupils and shifting the same light from one retina to the other, then, should cause no change in the drive to either pupil. However, if the test is performed on a patient whose left retina, for example, is less sensitive than the right, then both pupils will constrict each time the right eye is illuminated and both will dilate each time the light shifts to the left eye. Such a result is called a Relative Afferent Pupillary Defect (RAPD). (It is relative because it will only appear if the sensitivities of the two eyes differ; it is afferent because, at least when considering a simplified model of the anatomy, it must result from an imbalance somewhere before the signals from the two eyes converge to drive both pupils.)
Cited by 0
Joseph N. Mait · Journal of the Optical Society of America A · 1987
A procedure for designing pupil functions for four-channel, three-channel, and two-channel syntheses of complex incoherent point-spread functions is presented. This procedure is then generalized for synthesis of multiple bipolar point-spread functions. Examples of pupil-function design for complex syntheses are also presented.
Cited by 15
Bei Zhang, Suejit Pechprasarn, Jing Zhang et al. · Optics Express · 2012
Surface Plasmon microscopy can measure local changes of refractive index on the micron scale. Interferometric plasmon imaging delivers quantitative high spatial resolution sensitive to refractive index. In addition the so called V(z) method allows image contrast to be controlled by varying the sample defocus without substantially degrading spatial resolution. Here, we show how a confocal system provides a simpler and more stable alternative. This system, however, places greater demands on the dynamic range of the system. We therefore use a spatial light modulator to engineer the microscope pupil function to suppress light that does not contribute to the signal.
Cited by 37Open access
Sudhakar Prasad · Optics Letters · 2013
A simple approach based on the use of a properly designed pupil-phase profile can yield a 3D point-spread function (PSF) that rotates with changing defocus, while keeping its transverse shape approximately invariant over ±3-4 waves of defocus. Unlike Gauss-Laguerre mode-based approaches, it generalizes readily for encoding spherical aberration too via PSF rotation.
Cited by 84
Rafael G. González-Acuña · Journal of the Optical Society of America A · 2021
Here we present a method to design a stigmatic lens with a user-defined apodization pupil function. The motive is that the apodization pupil function is required by Richards-Wolf diffraction integrals to compute non-paraxial diffraction patterns. Then, the user-defined apodization pupil function can be chosen such that the focus spot obtained by the stigmatic lens is smaller. The mentioned method is based on numerically solving a non-linear differential equation.
Cited by 5
Shinji Shirakawa, Satoshi ISHIKAWA · PubMed · 1992
Pupil is richly innervated by autonomic nerves. Therefore, its size or movement well reflects the autonomic nervous function. By analyzing dynamics of pupil movement for light stimulus followed by infrared video-pupillography, the abnormality of autonomic nervous system can be expressed in a quantitative manner. Clinical applications of pupillography and pharmacological examination to Horner syndrome, Adie syndrome, diabetes mellitus, pupillary involvement of Behçet disease, pupil of brain death and patients with chemical sensitivity have been described. Segmental spasm of iris in Horner and Aide syndrome, especially, nasal side of iridoplegia was seen in early stage of Aide syndrome from pupillary dynamics to light stimulus. An involvement of sympathetic nerve subserving iris dilator muscle was confirmed from pupillography, drug reaction to topically applied l-epinephrine in the diabetics. An involvement of cholinergic nerve which subserve the iris sphincter muscle was seen in Behçet disease when there was no manifest eye involvement. Mild mydriasis in brain death patients was seen under denervation of central nervous system. Dysfunction of sympathetic nerve from pupillary light reflex in chemically sensitive patients for cholinated hydrocarbon pesticides.
Cited by 5
Ali Abd Almisreb, Nooritawati Md Tahir, Mustaffa Samad · 2010
Iris recognition system is one of the most reliable identification systems. However these systems are still uncommon because of many drawbacks for instance unreal time processing and inefficient identification methods. One of the critical tasks in iris recognition is detection of pupil. Pupil boundary detection method depended on the circular or elliptic shape of the pupil which could lead to inaccurate results of boundary detection. Thus, this can affect on the next step of iris recognition systems. Therefore, in this paper, we proposed a new method for pupil boundary detection. This method is based on thresholding the eye image by using the negative function. Next, the Four Neighbors method is used to detect the pupil boundary. Our method was tested on all CASIA V1.0 eye images and we attained 100% pupil boundary detection accuracy with acceptable computational time that can be implemented for real time processing.
Cited by 3
Simon B. Laughlin · Ophthalmic and Physiological Optics · 1992
Cited by 83
Simon B. Laughlin · Ophthalmic and Physiological Optics · 1992
Cited by 2
Hisao Ishigaki, Masaru Miyao, Sin'ya Ishihara · PubMed · 1991
Exercise was found to dilate the pupil area while the exercise took place, while the area showed constriction following the exercise period. Exercise-induced change in the size of the pupil was minimal. Pupillary dilation was greatest under conditions of maximal exercise. In exercise under a consistent load, pupillary dilation increased as the exercise time was prolonged. With lower lighting, there was virtually no dilation with exercise.
Cited by 23