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- 2018
- Image processing
- Infrared camera
- Eye movement
- Non-contact switch
- Optoelectronic Information Science and Engineering
- Gunma University
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Eye safe emission in Tm3+/Ho3+ and Yb3+/Tm3+ co-doped optical fibers fabricated using MCVD-CDS system
摘要： The RE-co-doped silica optical fibers emitting in the eye-safe spectral range are still attractive for new applications like LIDAR, pollution monitoring, navigation, and free-space optical communication. High gain and beam quality of fiber sources based on large mode area (LMA) active fibers can be fabricated by the well-known Modified Chemical Vapor Deposition (MCVD) technology improved by the chelate doping system. Considering silica matrix, the most interesting co-dopants in the region above 1400 nm are thulium and holmium. In the paper Tm3t/Ho3t and Yb3t/Tm3t co-doped silica optical fibers (refractive index and rare earth distribution profile, luminescence) are presented. Their respective emission spectra has been measured over the range 1550–2150 nm for Tm3t/Ho3t (exc. at 796 nm) and 1600–2100 nm for Yb3t/Tm3t (exc. at 976 nm). A wide luminescent spectrum has been recorded from RE co-doping of silica glass during the MCVD process and we were able to achieve the appropriate and uniform concentration for getting the conditions of energy transfer. The fabrication and characterization of Tm3t/Ho3t and Yb3t/Tm3t co-doped optical fibres are presented. The analysis of luminescence spectrum changes vs. fibre length has shown that there is Amplified Spontaneous Emission (ASE) at 1960 nm in Yb3t/Tm3t co-doped optical fibre. The possibilities of obtaining novel constructions of RE co-doped optical fibers for eye-safe emission region will be also shown.
关键词： Modified chemical vapor deposition (MCVD),Optical fibers,Lanthanides,Eye-safe emission
更新于2025-09-23 15:19:57
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Optical Mouse Sensor for Eye Blink Detection and Pupil Tracking: Application in a Low-Cost Eye-Controlled Pointing Device
摘要： In this paper, a new application of the optical mouse sensor is presented. The optical mouse is used as a main low-cost infrared vision system of a new proposal of a head-mounted human-computer interaction (HCI) device controlled by eye movements. The default optical mouse sensor lens and illumination source are replaced in order to improve its ?eld of view and capture entire eye images. A complementary 8-bit microcontroller is used to acquire and process these images with two optimized algorithms to detect forced eye blinks and pupil displacements which are translated to computer pointer actions. This proposal introduces an inexpensive and approachable plug and play (PnP) device for people with severe disability in the upper extremities, neck, and head. The presented pointing device performs standard computer mouse actions with no extra software required. It uses the human interface device (HID) standard class of the universal serial bus (USB) increasing its compatibility for most computer platforms. This new device approach is aimed at improving comfortability and portability of the current commercial devices with simple installation and calibration. Several performance tests were done with di?erent volunteer users obtaining an average pupil detection error of 0.34 pixels with a successful detection in 82.6% of all mouse events requested by means of pupil tracking.
关键词： human-computer interaction,low-cost device,optical mouse sensor,pupil tracking,eye blink detection
更新于2025-09-23 15:19:57
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Evaluation of patients with diffuse unilateral subacute neuroretinitis by spectral domain optical coherence tomography with enhanced depth imaging
摘要： Background: The purpose of this study was to determine the value of spectral domain optical coherence tomography (SD-OCT) in assessing patients with diffuse unilateral subacute neuroretinitis (DUSN). Methods: This was an observational case series with clinical imaging correlation performed at the Retina and Vitreous Institute of Londrina and State University of Londrina, Paraná, Brazil. The series comprised ten consecutive patients with a confirmed diagnosis of DUSN, ie, seven patients with late-stage disease and three with early-stage disease, who were assessed by SD-OCT for mean macular, retinal nerve fiber layer, and choroidal thickness using enhanced depth imaging software. Results: Comparing the affected eye with the healthy fellow eye, significant diffuse atrophy of the retinal layers with a decrease in mean macular (P=0.004) and retinal nerve fiber layer (P=0.002) thickness was found in all cases. There was no difference in choroidal thickness (P=0.262). Conclusion: The correlation of SD-OCT results with central vision and funduscopic findings may explain the profound loss of visual function in patients with DUSN.
关键词： enhanced depth imaging,diffuse unilateral subacute neuroretinitis,optical coherence tomography,eye infections,parasitic,retinitis
更新于2025-09-19 17:15:36
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A novel 1,8-naphthalimide as highly selective naked-eye and ratiometric fluorescent sensor for detection of Hg2+ ions
摘要： A novel colorimetric and ratiometric fluorescent chemosensor, 2-(2-mercaptophenyl)-1H-benzo[de]isoquinoline-1,3-(2H)-dione (L3) is reported for Hg2+ ions. The selective binding of Hg2+ to L3 afforded new absorbance and fluorescence peaks at 438 nm and 480 nm, in addition to the existing bands of L3 at 332 nm and 376 nm. It also showed apparent colour change from colourless to yellowish green and weak fluorescent to bright yellowish green strong fluorescent due to selective binding of Hg2+ ion. The sensor forms a 1:1 stoichiometry with high binding constants (3.89 × 10^4 mol^-1 L) and limit of detection 1.74 × 10^-8 M with high selectivity and sensitivity towards Hg2+ in the presence of other interfering metal ions. More importantly, it has good practicability in environmental water sample. The outcome of photo-physical experiment has also been in good accordance with the time-resolved fluorescence life decays and the density functional theory (DFT) estimations. Moreover, the L3-Hg2+ solution displayed high colorimetric and fluorimetric reversibility via the addition of KI. This reversibility in fluorescence showed potential applicability of chemosensor L3 as 'on–off–on' naked eye sensor.
关键词： Molecular logic gate,Red-shift,DFT,Off–on–off Hg2+ chemosensor,Naked eye detection,Ratiometric fluorescence
更新于2025-09-19 17:15:36
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[ACM Press the 2018 ACM Symposium - Warsaw, Poland (2018.06.14-2018.06.17)] Proceedings of the 2018 ACM Symposium on Eye Tracking Research & Applications - ETRA '18 - Training operational monitoring in future ATCOs using eye tracking
摘要： Improved technological possibilities continue to increase the significance of operational monitoring in air traffic control (ATC). The role of the air traffic controller (ATCO) will change in that they will have to monitor the operations of an automated system for failures. In order to take over control when automation fails, future ATCOs will need to be trained. While current ATC training is mainly based on performance indicators, this study will focus on the benefit of using eye tracking in future ATC training. Utilizing a low-fidelity operational monitoring task, a model of how attention should be allocated in case of malfunction will be derived. Based on this model, one group of ATC novices will receive training on how to allocate their attention appropriately (treatment). The other group will receive no training (control). Eye movements will be recorded to investigate how attention is allocated and if the training is successful. Performance measures will be used to evaluate the effectiveness of the training.
关键词： air traffic control,Monitoring,aviation,eye movements,training,automation
更新于2025-09-19 17:15:36
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Color Doppler imaging in thyroid eye disease and its correlation to disease activity
摘要： Purpose: To evaluate alterations in orbital color Doppler imaging (CDI) parameters and their correlation to disease activity and severity in patients with thyroid eye disease (TED). Methods: Seventy-six orbits of 45 TED patients and 40 orbits of 40 normal controls were enrolled in this cross-sectional study. According to clinical activity score (CAS), patients were categorized to active (CAS ≥ 3) or inactive disease (CAS < 3). Patients were also classified as having mild, moderate or severe disease. Peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI) in ophthalmic artery and central retinal artery, and maximum and minimum velocity in superior ophthalmic vein and central retinal vein were determined in all subjects. Results: There was a significant difference in maximum velocity of superior ophthalmic vein and EDV and RI of ophthalmic artery between patients with TED and normal subjects. Superior ophthalmic vein maximum and minimum velocity and ophthalmic artery RI were significantly higher in patients with active disease than inactive cases. Disease severity did not affect the blood flow parameters independently. A cutoff point of 3.99 cm/s in superior ophthalmic vein maximum velocity yielded a sensitivity of 91.2% and specificity of 81.2% in detecting active disease. Conclusion: Retrobulbar blood flow is altered in TED and is related to disease activity. Superior ophthalmic vein maximum velocity could be helpful in differentiation of active and inactive cases.
关键词： Clinical activity score,color Doppler imaging,thyroid eye disease
更新于2025-09-19 17:15:36
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Studies on pelletized lithium magnesium borate TL material for eye lens dosimetry
摘要： Recent epidemiological studies in various cohorts confirm that radiation induced cataract may occur at a threshold dose as low as 0.5 Gy. ICRP has recognized the higher radiosensitivity of eye lens and recommended to reduce annual eye lens dose limit from 150 mSv to 20 mSv. Present dosimetry for eye lens is largely based on LiF based dosimeters. The present work is an attempt towards using near tissue equivalent lithium borate material namely lithium magnesium borate doped with terbium (LMB:Tb) in eye lens dosimetry. The material in powder form was synthesized using solid state sintering method and pelletized using poly tetra fluoro ethylene (PTFE) as binding agent. It was observed that 130 mg of 1mm thick LMB:Tb pellet bound with PTFE showed stable glow curve structure and attractive dosimetric features in terms of sensitivity, fading, linearity, reusability etc. A proposal of 1.5 mm Teflon encapsulation corresponding to tissue equivalent thickness of 3 mm was put forward for an ideal dosimeter for the measurement in terms of Hp(3). Energy and angular dependence studies based on FLUKA simulations suggest a flat response for the prototype design. In addition to PTFE, various tissue equivalent encapsulations such as polyimide, polyamide 6 and PMMA were also evaluated using FLUKA code.
关键词： thermoluminescence,Eye lens dosimetry,lithium borate phosphor
更新于2025-09-19 17:15:36
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Evaluation of tear meniscus dimensions using anterior segment optical coherence tomography in video terminal display workers
摘要： Background: To evaluate tear meniscus height and tear meniscus area measured by optical coherence tomography (OCT) and to determine the prevalence of dry eye disease in video display terminal (VDT) users. Methods: This was a case–control study performed on VDT users. The case group consisted of 53 subjects who vocationally use VDT more than six hours per day and the control group consisted of 49 subjects who used VDT not more than one hour per day. The pre-vocational and post-vocational tear meniscus height and tear meniscus area measurements were performed twice in one day using OCT. Tear-film break-up time, Schirmer’s test, Ocular Surface Disease Index score and corneal staining score measurements were performed in all subjects. Results: The mean age was 38.9 (cid:1) 5.5 years in VDT users and 37.8 (cid:1) 5.8 years in the control group (p = 0.426). Twenty patients (37.7 per cent) had dry eye disease in VDT users and five patients (10.2 per cent) had dry eye disease in the control group (p = 0.001). The mean tear meniscus height and tear meniscus area values (pre-vocational and post-vocational) were significantly lower in VDT users than in the control group (p < 0.001, p < 0.001, p = 0.024 and p < 0.001, respectively). The Schirmer’s test results, Ocular Surface Disease Index scores, corneal staining scores and tear-film break-up time values revealed significant differences between VDT users and control subjects (p = 0.002, p = 0.006, p < 0.001 and p < 0.001, respectively). In addition, significant correlations were demonstrated between Schirmer’s test results, Ocular Surface Disease Index scores, corneal staining scores, tear-film break-up time measurements, tear meniscus height results and tear meniscus area values. Conclusion: Tear meniscus evaluation using OCT is an effective, non-invasive and sensitive method for detection of dry eye disease in VDT users.
关键词： dry eye disease,tear meniscus height,video display terminal,optical coherence tomography,tear meniscus area
更新于2025-09-19 17:15:36
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Predictive remapping of visual features beyond saccadic targets
摘要： Visual stability is thought to be mediated by predictive remapping of the relevant object information from its current, presaccadic location to its future, postsaccadic location on the retina. However, it is heavily debated whether and what feature information is predictively remapped during the presaccadic interval. Here we examined the spatial and featural properties of predictive remapping in a set of three psychophysical studies. We made use of an orientation-adaptation paradigm, in which we induced a tilt aftereffect by prolonged exposure to an oriented adaptor stimulus. Following this adaptation phase, a test stimulus was presented shortly before saccade onset. We found strong evidence for predictive remapping of the features of this test stimulus presented shortly before saccade onset, evidenced by a large tilt aftereffect elicited when the adaptor was positioned at the postsaccadic retinal location of the test stimulus. Conversely, the adaptation state itself, caused by the exposure to the adaptor stimulus, was not predictively remapped. Furthermore, we establish that predictive remapping also occurs for stimuli that are not saccade targets, pointing toward a forward remapping process operating across the whole visual field. Together, our findings suggest that predictive feature remapping of object information plays an important role in mediating visual stability.
关键词： feature remapping,visual stability,adaptation,eye movements
更新于2025-09-19 17:15:36
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Real-time naked-eye recognizable temperature monitoring based on Ho <sup>3+</sup> (or Tm <sup>3+</sup> )-activated NaYF <sub/>4</sub> upconversion nanowires <i>via</i> visual multicolor alteration
摘要： Non-contact thermometry for real-time temperature monitoring is a challenging research topic. Advances in microelectronics and biotechnology demand precise temperature monitoring with novel materials and approaches, where conventional thermometers are burdensome because of employing expensive additional equipment (e.g. spectrometers) and further data processing. Lanthanide-doped upconversion nanomaterials that can convert single near-infrared excitation into multicolor visible emissions open the door for a novel strategy to thermometry. Herein, a real-time naked-eye recognizable color change was achieved based on Ho3+ (or Tm3+)-activated NaYF4 upconversion nanowires, depending on the different spectral sensitivities of the blue, green and red upconversion emissions to temperature. Furthermore, the luminescence color can be also directly modulated by only using 975 nm laser radiation, which extended their application scope. These desirable properties make upconversion nanomaterials promising for temperature monitoring, anti-counterfeiting, and multicolor temperature probing applications with the advantages of being simple, convenient and unreplicable.
关键词： nanowires,naked-eye recognizable,upconversion,temperature monitoring,multicolor alteration
更新于2025-09-19 17:15:36