Types Of Blinking Research Articles

Performance Improvement of 3D-CNN for Blink Types Classification by Data Augmentation

Performance Improvement of 3D-CNN for Blink Types Classification by Data Augmentation

Conversion of Photoluminescence Blinking Types in Single Colloidal Quantum Dots.

Almost all colloidal quantum dots (QDs) exhibit undesired photoluminescence (PL) blinking, which poses a significant obstacle to their use in numerous luminescence applications. An in-depth study of the blinking behavior, along with the associated mechanisms, can provide critical opportunities for fabricating high-quality QDs for diverse applications. Here the blinking of a large series of colloidal QDs is investigated with different surface ligands, particle sizes, shell thicknesses, and compositions. It is found that the blinking behavior of single alloyed CdSe/ZnS QDs with a shell thickness of up to 2nm undergoes an irreversible conversion from Auger-blinking to band-edge carrier blinking (BC-blinking). Contrastingly, single perovskite QDs with particle sizes smaller than their Bohr diameters exhibit reversible conversion between BC-blinking and more pronounced Auger-blinking. Changes in the effective trapping sites under different excitation conditions are found to be responsible for the blinking type conversions. Additionally, changes in shell thickness and particle size of QDs have a significant effect on the blinking type conversions due to altered wavefunction overlap between excitons and effective trapping sites. This study elucidates the discrepancies in the blinking behavior of various QD samples observed in previous reports and provides deeper understanding of the mechanisms underlying diverse types of blinking.

Detailed Analysis of Blink Types Classification Using a 3D Convolutional Neural Network

Detailed Analysis of Blink Types Classification Using a 3D Convolutional Neural Network

Blinking and upper eyelid morphology

PurposeTo explore blinking patterns and sagittal eyelid misalignment in the East Asian eye. MethodsForty-four participants (22 females; age 26 ± 5 years; 52% of East Asian ethnicity) were enrolled in this pilot study and subdivided, based on upper eyelid crease presence and extent, into single (n = 10), partial (n = 11) or double (n = 23) eyelid crease groups. Blinking was filmed surreptitiously with high-speed video simultaneously from an inferior temporal and frontal view. Spontaneous blink rate and type (incomplete, almost complete, or complete) were assessed over a 30 s period. Sagittal misalignment of the lids on closure was graded during complete spontaneous blinks, voluntary lid closure and voluntary maximal lid contraction (squeezing). A 0.15 µL drop of lissamine green was placed on the central lower lid margin and the number and type of blinks required to eliminate the drop informed complete palpebral apposition during blinking. ResultsMean ± SD blink rates averaged 16.9 ± 10.5 blinks/minute. The proportion of incomplete blinks was 83 ± 22% in single, 58 ± 35% in partial and 59 ± 30% in double eyelid crease groups. The sagittal misalignment of the lid margins during blinking was limited to approximately one-third of the lid margin width; this was similar for all lid morphologies and blink types. The lissamine green drop was eliminated only by voluntary maximal lid contraction, and was similar in all groups (p = 0.97). ConclusionsIncomplete blinking and sagittal lid misalignment of the central eyelid margin predominate in habitual blinking, irrespective of lid morphology.

Detection of the spontaneous blinking pattern of dry eye patients using the machine learning method

Objective: To establish a method to record the spontaneous blink pattern with a machine learning model, and to clarify the spontaneous blink pattern in patients with dry eye. Methods: It was a cross-setional study.We selected 357 dry eye patients (102 males and 255 females), aged (46.2±13.3) years, who visited corneal specialist clinics of Beijing Tongren Eye Center in 2019, as the dry eye group. The control group enrolled 152 normal controls, including 32 males and 120 females, aged (48.1±13.9) years. All participants completed the Ocular Surface Disease Index questionnaire, blink video capture, lipid layer thickness measurement, tear break-up time measurement, corneal fluorescein staining, and Schirmer Ⅱ test. Based on the assembled model built using UNet image segmentation algorithm and ResNet image classification algorithm, single frames of the blink video were analyzed, and then the palpebral opening height of each frame was obtained in order to establish a spontaneous blink wave. Finally, the characteristics of spontaneous blinks in dry eye patients were analyzed based on different types of complete blinks (types A, B and C) and partial blinks (types Ⅰ, Ⅱ and Ⅲ). Independent sample t test and Wilcoxon rank-sum test were used to judge if there was significant difference between the dry eye group and the normal group. Results: The accuracy of the segmentation model and the classification model was 96.3% and 96.0%, respectively, and the consistency with the manual analysis was 97.9%. In dry eye patients, the number of blinks was 30 (18, 42)/min, which was higher than that in normal controls [20 (9, 46)/min] (U=18 132.50, P=0.002). The number of complete blinks in dry eye cases was significantly lower than that in normal controls [6 (3, 24)/min vs. 12 (3,33)/min; U=12 361.00, P=0.016], and the number of partial blinks was significantly higher than that in normal controls [15 (6, 27)/min vs. 3 (0, 10)/min; U=22 839.00, P<0.001]. In complete blinks, the proportion of type A blinks in dry eye patients was significantly higher than that in normal controls [53.7% (2 796/5 177) vs. 39.3% (633/1 698); χ²=101.83, P<0.001]; in partial blinks, the proportion of type Ⅱ blinks in dry eye patients was significantly higher than that in normal controls [36.0%(2 334/6 477) vs. 29.6%(126/426); χ²=6.99, P=0.007]. The average interblink interval of dry eye patients was 1.2 s, which was not significantly different from that of normal controls (1.1 s; U=15 230.00, P=0.093). The eyelid closed phase of dry eye patients was 0.8 s, which was significantly shorter than that of normal controls (1.3 s; U=16 291.50, P=0.006). There were no significant differences in eyelid closing phase, early opening phase and late opening phase between the two groups (all P>0.05). Conclusions: In dry eye patients, the number of partial blinks increased, the number of complete blinks decreased, and the duration of eyelid closed phase shortened significantly. The main blink patterns of dry eye patients included type Ⅱ partial blinks with a reduced closure amplitude and type A complete blinks with a shortened closure time.

Chronologic Analysis of Tear Dynamics on Blinking Using Quantitative Manometry in Healthy Humans.

To analyze the tear dynamics during blinking by measuring the inner pressure of the upper lacrimal drainage system. This observational study involved 11 healthy bi- or tricenarian volunteers. Direct manometry was performed using a fiber optic pressure sensor inserted into the conjunctival sac, upper/lower canaliculus (5 mm from punctum), and inferior lacrimal sac (15 mm from punctum) during both involuntary and intentional tight blinking. Pressure was measured 200 times/second during 3 separate blinks and then chronologically analyzed. In all subjects of all locations during both types of blinking, the inner pressures during the stationary eyelid closing/opening were positive/approximately zero, while a positive/negative pressure spike was observed during the eyelid closing/opening movement. The averages of the maximum pressure in the spike during the intentional tight blinking (tPmax: mm Hg) in the conjunctival sac, upper/lower canaliculus, and lacrimal sac were 8.00, 12.39/12.93, and 10.59, respectively, while for the minimum (tPmin: mm Hg), the pressures were -3.18, -3.91/-3.43, and -3.31, respectively. The tPmax and tPmin in the lacrimal duct were positively correlated with that of the conjunctival sac, which suggested synchronism of the drainage system. However, the tPmax in the canaliculus was significantly higher than that of the conjunctival sac, which suggested that tears do not flow from the conjunctival sac into the lacrimal duct during eyelid closure. The upper lacrimal drainage system functions as one united lumen in the lacrimal pump. The positive /negative pressure spike is essential for the lacrimal pump to efficiently eject/aspirate the tear from the lacrimal/conjunctival sac.

Ultrafast intraband Auger process in self-doped colloidal quantum dots

Summary Investigating the separate dynamics of electrons and holes has been challenging, although it is critical for the fundamental understanding of semiconducting nanomaterials. n-Type self-doped colloidal quantum dots (CQDs) with excess electrons occupying the low-lying state in the conduction band (CB) have attracted a great deal of attention because of not only their potential applications to infrared optoelectronics but also their intrinsic system that offers a platform for investigating electron dynamics without elusive contributions from holes in the valence band. Here, we show an unprecedented ultrafast intraband Auger process, electron relaxation between spin-orbit coupling states, and exciton-to-ligand vibrational energy transfer process that all occur exclusively in the CB of the self-doped β-HgS CQDs. The electron dynamics obtained by femtosecond mid-infrared spectroscopy will pave the way for further understanding of the blinking phenomenon, disproportionate charging in light-emitting diodes, and hot electron dynamics in higher quantum states coupled to surface states of CQDs.

Blink input interface enabling multiple candidate selection through sound feedback

Several input interfaces that employ eye-blinking detection have been proposed. These input interfaces can detect operating intentions indicated by eye-blink actions. In this study, we propose a new blink input interface with the aim of increasing the classifiable blink types in addition to the regular voluntary blink. The proposed interface employs a sound feedback that facilitates multiple candidate selection. The feedback sound represents each input candidate and is generated while switching over time. This interface enables the user to input their operating intentions by controlling the timing of eye opening. We developed a prototype with the proposed interface and evaluated the system. The results indicated that a total classification rate of 96.5% is achieved for four types of voluntary blinks with 10 subjects. This classification rate is in accordance that of our previous report for two types of voluntary blinks. Thus, we concluded that our proposed method is reliable.

Comparative analysis of spontaneous blinking and the corneal reflex.

Ocular surface health, the cognitive status, psychological health or human neurological disorders, among others, can be assessed by studying eye blinking, which can be differentiated in spontaneous, reflex and voluntary. Its diagnostic potential has provided a great number of works that evaluate their characteristics and variations depending on the subject's condition (sex, tiredness, health, …). The objective of this study was to analyse the differences in blinking kinematics of spontaneous and reflex blinks, distinguishing between direct and consensual reflexes, using a self-developed, non-invasive and image processing-based method. A video-oculography system is proposed using an air jet driven by a syringe to induce reflex and a high-speed camera to record the blinking of both eyes. The light intensity diffused by the eye changes during blinking and peaks when the eyelid closes. Sixty-second sequences were recorded of 25 subjects blinking. Intensity curves were off-line fitted to an exponentially modified Gaussian (EMG) function, whose σ, μ and τ parameters were analysed. A two-way analysis of variance (ANOVA) of these parameters was conducted to test the influence of the subject, the eye and blink type. In the closing phase, direct and consensual corneal reflexes are faster than spontaneous blinking, but there was no significant difference between them, nor between right and left eyes. In the opening phase, the direct corneal reflex was the slowest and significant differences appeared between right and left eyes.

Subjective and Objective Evaluation of the Effect of Blink Type on Tear-film Breakup Time and Its Estimation.

While evaluating the tear-film breakup time, a careful set of precise instructions should be given to the subjects regarding the blink type because it substantially impacts the assessment of tear-film surface quality. The purpose of this study was to determine to what extent the type of blink affects the tear-film breakup time and its assessment using two types of videokeratoscopes and the fluorescein test. Thirty-three volunteers were assessed considering two different types of blinks: natural (short) and forced (unnaturally prolonged). Objective noninvasive breakup time estimation was performed using Oculus Keratograph 5M and Medmont E300, both equipped with tear-film analysis modules, followed by the fluorescein test. In addition, while overviewing videokeratoscopy recordings, noninvasive breakup time was assessed subjectively by one experienced observer marking the first noticeable distortion in the Placido-disk pattern. Statistical analyses included two-way ANOVA and paired-sample t test. The agreement between blinking and measuring modalities was assessed using Bland-Altman plots. Forced blink significantly shortened the tear-film breakup time in all measuring modalities (two-way ANOVA, P = .003). The mean difference between breakup time after natural and forced blink was 3.2 (P = .002), 2.4 (P = .005), and 2.1 seconds (P = .002), for Keratograph 5M, E300, and fluorescein test, respectively. The group median of differences between objective and subjective noninvasive breakup time was less than 1 second with both videokeratoscopes. The objective noninvasive breakup time measured with Keratograph 5M was significantly longer than those with E300 and fluorescein test (both P < .001). No statistically significant difference was found between E300 objective assessment and fluorescein test (P = .19). Forced blinks affect the assessment of tear-film stability. Hence, attention should be given in instructing the subjects before tear-film breakup time evaluation irrespectively to the method of measurement.

Ictal lid movements - Blinks and lid saccades

Two types of lid movements, lid saccades and blinks, have discrete kinematic properties and physiology. These differences are reflected in distinct phenomenology of disorders affecting their neural substrate. Proof of this principle was seen in two cases, one with parietal eyefield epileptiform discharges and the other with temporal lobe seizures. The lid movements in the patient with epileptiform discharges in the eyefield were rhythmic, yoked, and had rapid upward component that instantaneously followed slow downward drift. These cyclic movements strikingly resembled nystagmus, but unlike typical eye nystagmus, the rapid upward component was pathological and seemed to involve saccadic mechanism. We suggest terms “ictal lid saccade” or “ictal lid nystagmus” to describe such phenomenology. In contrast, the patient with temporal lobe seizures had ipsilateral lid movements with rapid downward trajectories resembling reflex or spontaneous blinks. The term “ictal blink” is appropriate for this phenomenology. Schematic organization of the underlying neural circuit for lid saccade (A) and blink (B). The caricature of trajectory of lid saccade (C) and blink (D). In the caricature of the lid saccade caricature, vertical lid position is schematized in blue color, while corresponding lid velocity is schematized in brown color. The bottom row schematized EMG activity from levator palpebrae (LP, green color) and orbicularis oculi (OO, light brown color). In schematic in panel C, D, the x-axis always represents time, and schematized EMG activity is temporally matched with schematized lid position and lid velocity.

Advanced eye-gaze input system with two types of voluntary blinks

Recently, several eye-gaze input systems have been developed. Some of these systems consider the eye-blinking action to be additional input information. A main purpose of eye-gaze input systems is to serve as a communication aid for the severely disabled. The input system, which employs eye blinks as command inputs, needs to identify voluntary (conscious) blinks. In the past, we developed an eye-gaze input system for the creation of Japanese text. Our previous system employed an indicator selection method for command inputs. This system was able to identify two types of voluntary blinks. These two types of voluntary blinks work as functions governing indicator selection and error correction, respectively. In the evaluation experiment of the previous system, errors were occasionally observed in the estimation of the number of indicators at which the user was gazing. In this study, we propose a new input system that employs a selection method based on a novel indicator estimation algorithm. We conducted an experiment to evaluate the performance of Japanese text creation using our new input system. This study reports that using our new input system improves the speed of text input. In addition, we demonstrate a comparison of the various related eye-gaze input systems.

Organic–Inorganic FAPbBr3 Perovskite Quantum Dots as a Quantum Light Source: Single-Photon Emission and Blinking Behaviors

In the past decade, lead halide perovskite nanocrystals or quantum dots (QDs) have attracted keen interest due to their potential applications in many optoelectronic systems. In addition, all-inorganic (CsPbX3) perovskite QDs are suggested to be efficient single photon emitting centers. Herein, we study the photon emission properties of recently synthesized organic–inorganic FAPbBr3 QDs. Our results show that individual FAPbBr3 QDs can act as good single-photon sources with very low multiphoton emission probability achieved by extremely fast nonradiative Auger recombination. However, they exhibit photodegradation and fluorescence intensity intermittency, called blinking. By analyzing the ON(OFF) duration time distribution, particularly the OFF duration times, we suggest that two types of blinking (type-A and type-B) simultaneously contribute to the blinking behavior of FAPbBr3 QDs. In type-A and type-B blinking, the ON/OFF periods are attributed to charged/discharged states and to activation/deactivation of fast nonradiative recombination centers, respectively. By analyzing the ON/OFF duration cutoff time as a function of the excitation intensity, we verify that type-A blinking is caused mainly by diffusion-controlled electron transfer, partially accompanied by Auger ionization processes.

Real-time eye blink and wink detection for object selection in HCI systems

This paper presents an approach for real-time detection of three types of eye blinks: eye blink (blinking both eyes simultaneously), left and right winks. The process of blink detection has been divided into four parts viz. face localization in facial images acquired through a video camera, eye pair localization, pixels’ motion analysis using optical flow technique, and classification of eye blinks. Blink detection has been performed using a video camera and MATLAB software with image processing and computer vision toolbox. The algorithm takes about 60 ms time for processing a frame and 250 ms time for confirmation and classification of the detected blink. An experiment was conducted to evaluate the performance of the proposed approach in which 10 users voluntarily participated. The performance of the proposed method has been tested under two lighting conditions: natural lighting conditions and controlled lighting conditions. Also, the performance has been tested by varying the distance of the user from the camera. Here, it is observed that the system gives best performance when used under controlled lighting conditions and the user sitting at a distance of about 0.5 m. Accuracy of the proposed approach has been found to be 96, 92 and 88% for detection of eye blink, left wink and right wink, respectively. The proposed method has also been tested on ZJU dataset where it has given precision, detection accuracy and false alarm rate of values 94.11, 91.2 and 1.54%, respectively. The proposed system has been used and evaluated for performing various mouse analogous functions using eye blinks and winks. It has given an accuracy of 90, 80 and 90% in performing left click, double click, and right click operations, respectively.

An Automatic Classification Method for Involuntary and Two Types of Voluntary Blinks

SUMMARYInput systems using eye blinks have been proposed. A main purpose of these systems is communication aid for the severely disabled. For employing eye blinks as a command input, these input systems need to detect voluntary (conscious) blinks. We developed a measurement method for variation in pixels of open‐eye area from an image sequence. This measurement method enables us to extract blinking waver patterns. We previously proposed an automatic classification method between one type of voluntary blinks and involuntary (unconscious) blinks. If the type of classifiable voluntary blinks increase, we can assign an individual command to each type. Applying this blink type classification to a human–computer interface will improve the efficiency when inputting commands. In this paper, we introduce a new type of voluntary blinks to increase classifiable blink type. In addition, our classification method is extended for automatic classification between two types of voluntary blinks and involuntary blinks. This new classification method is realized by two blink type determinations based on wave pattern parameters that we employ. We clarify proper parameter combinations for the new classification method. Using these proper parameter combinations, we achieved approximately 95% classification rates for 10 subjects.

"Supertrap" at Work: Extremely Efficient Nonradiative Recombination Channels in MAPbI3 Perovskites Revealed by Luminescence Super-Resolution Imaging and Spectroscopy.

Organo-metal halide perovskites are some of the most promising materials for the new generation of low-cost photovoltaic and light-emitting devices. Their solution processability is a beneficial trait, although it leads to a spatial inhomogeneity of perovskite films with a variation of the trap state density at the nanoscale. Comprehending their properties using traditional spectroscopy therefore becomes difficult, calling for a combination with microscopy in order to see beyond the ensemble-averaged response. We studied photoluminescence (PL) blinking of micrometer-sized individual methylammonium lead iodide (MAPbI3) perovskite polycrystals, as well as monocrystalline microrods up to 10 μm long. We correlated their PL dynamics with structure employing scanning electron and optical super-resolution microscopy. Combining super-resolution localization imaging and super-resolution optical fluctuation imaging (SOFI), we could detect and quantify preferential emitting regions in polycrystals exhibiting different types of blinking. We propose that blinking in MAPbI3 occurs by the activation/passivation of a "supertrap" which presumably is a donor-acceptor pair able to trap both electrons and holes. As such, nonradiative recombination via supertraps, in spite being present at a rather low concentrations (1012-1015 cm-3), is much more efficient than via all other defect states present in the material at higher concentrations (1016-1018 cm-3). We speculate that activation/deactivation of a supertrap occurs by its temporary dissociation into free donor and acceptor impurities. We found that supertraps are most efficient in structurally homogeneous and large MAPbI3 crystals where carrier diffusion is efficient, which may therefore pose limitations on the efficiency of perovskite-based devices.

A Calibration Method for Blink Type Classification

SUMMARYHuman–computer interaction systems that use eye blinks have been reported. One purpose of these systems is as a communication aid for persons with severe physical disabilities such as amyotrophic lateral sclerosis (ALS). Some of these systems classify the user's voluntary (conscious) blinks. If the voluntary blinks can be distinguished automatically, the usability of the input interface will be improved. We have proposed an eye blink extraction method that utilizes split interlaced images of the eye. These split images are odd‐ and even‐field images and are generated from interlaced images. The proposed method yields a time resolution that is double that of the 1080i Hi‐Vision format. We refer to this approach as a “frame splitting method”. We realized a method for automatic eye blink extraction using the frame splitting method. Based on this extraction method, we also proposed a blink type classification method in which a threshold is set within the duration of an eye blink. Our classification method requires a calibration process before measurement. In this paper, we clarify the required minimum number of eye blinks for calibration. We also discuss the performance of blink type classification using this calibration.

2種類の随意性瞬目と自発性瞬目の自動識別法

2種類の随意性瞬目と自発性瞬目の自動識別法

Neuromagnetic brain responses to other person's eye blinks seen on video.

Eye blinks, typically occurring 15–20 times per minute, rarely capture attention during face-to-face interaction. To determine the extent to which eye blinks affect the viewer's brain activity, we recorded magnetoencephalographic brain responses to natural blinks, and to the same blinks slowed down to 38% of the original speed. The stimuli were presented on video once every 2.3–6.2 s. As a control, we presented two horizontal black bars moving with the same time courses and the same extent as the eyelids in the blink video. Both types of blinks and bars elicited clear responses peaking at about 200 ms in the occipital areas, with no systematic differences between hemispheres. For the bars, these main responses were (as expected) weaker (by 24%) and later (by 33 ms) to slow-motion than normal-speed stimuli. For blinks, however, the responses to both normal-speed and slow-motion stimuli were of the same amplitude and latency. Our results demonstrate that the brain not only responds to other persons' eye blinks, but that the responses are as fast and of equal size even when the blinks are considerably slowed down. We interpret this finding to reflect the increased social salience of the slowed-down blinks that counteracted the general tendency of the brain to react more weakly and more slowly to slowly- vs. quickly-changing stimuli. This finding may relate to the social importance of facial gestures, including eye blinks.

FMRI Cortical Correlates of Spontaneous Eye Blinks in the Nonhuman Primate

Eyeblinks are defined as a rapid closing and opening of the eyelid. Three types of blinks are defined: spontaneous, reflexive, and voluntary. Here, we focus on the cortical correlates of spontaneous blinks, using functional magnetic resonance imaging (fMRI) in the nonhuman primate. Our observations reveal an ensemble of cortical regions processing the somatosensory, proprioceptive, peripheral visual, and possibly nociceptive consequences of blinks. These observations indicate that spontaneous blinks have consequences on the brain beyond the visual cortex, possibly contaminating fMRI protocols that generate in the participants heterogeneous blink behaviors. This is especially the case when these protocols induce (nonunusual) eye fatigue and corneal dryness due to demanding fixation requirements, as is the case here. Importantly, no blink related activations were observed in the prefrontal and parietal blinks motor command areas nor in the prefrontal, parietal, and medial temporal blink suppression areas. This indicates that the absence of activation in these areas is not a signature of the absence of blink contamination in the data. While these observations increase our understanding of the neural bases of spontaneous blinks, they also strongly call for new criteria to identify whether fMRI recordings are contaminated by a heterogeneous blink behavior or not.