Visual Angle Research Articles

Trans-saccadic integration for object recognition peters out with pre-saccadic object eccentricity as target-directed saccades become more saliency-driven

Bringing objects from peripheral locations to fovea via saccades facilitates their recognition. Human observers integrate pre- and post-saccadic information for recognition. This integration has only been investigated using instructed saccades to prescribed locations. Typically, the target has a fixed pre-saccadic location in an uncluttered scene and is viewed by a pre-determined post-saccadic duration. Consequently, whether trans-saccadic integration is limited or absent when the pre-saccadic target eccentricity is too large in cluttered scenes in unknown. Our study revealed this limit during visual exploration, when observers decided themselves when and to where to make their saccades. We asked thirty observers (400 trials each) to find and report as quickly as possible a target amongst 404 non-targets in an image spanning 57.3°×33.8° in visual angle. We measured the target’s pre-saccadic eccentricity e, the duration Tpre of the fixation before the saccade, and the post-saccadic foveal viewing duration Tpost. This Tpost increased with e before starting to saturate around eccentricity ep=10°−20°. Meanwhile, Tpre increased much more slowly with e and started decreasing before ep. These observations imply the following at sufficiently large pre-saccadic eccentricities: the trans-saccadic integration ceases, target recognition relies exclusively on post-saccadic foveal vision, decision to saccade to the target relies exclusively on target saliency rather than identification. These implications should be applicable to general behavior, although ep should depend on object and scene properties. They are consistent with the Central-peripheral Dichotomy that central and peripheral vision are specialized for seeing and looking, respectively.

Directed motion of cognitive active agents in a crowded three-way intersection

Understanding the navigation through semi-dense crowds at intersections poses a significant challenge in pedestrian dynamics, with implications for facility design and insights into emergent collective behavior. To tackle this problem, a system of cognitive active agents at a crowded three-way intersection is studied using Langevin simulations of intelligent active Brownian particles (iABPs) with directed visual perception (resulting in non-reciprocal interactions) and self-steering avoidance—without volume exclusion. We find that the emergent self-organization depends on agent maneuverability, goal fixation, and vision angle, and identify several forms of collective behavior, including localized flocking, jamming and percolation, and self-organized rotational flows. Additionally, we demonstrate that the motion of individual agents can be characterized by fractional Brownian motion and Lévy walk models across different parameter regimes. Moreover, despite the rich variety of collective behavior, the fundamental flow diagram shows a universal curve for different vision angles. Our research highlights the impact of collision avoidance, goal following, and vision angle on the individual and collective dynamics of interacting pedestrians.

Trans-retinal predictive signals of visual features are precise, saccade-specific and operate over a wide range of spatial frequencies.

Saccadic eye movements successively project the saccade target on two retinal locations: a peripheral one before the saccade, and the fovea after the saccade. Typically, performance in discriminating stimulus features changes between these two projections is very poor. However, a short (~ 200 ms) blanking of the target upon saccade onset drastically improves performance, demonstrating that a precise signal of the peripheral projection is retained during the saccade. While little is known about the nature of that transsaccadic signal, previous reports conjectured that it relies on information processed by the magnocellular system. Across two experiments, we investigated the feature blanking effect for a wide range of spatial frequencies (0.5 to 8 cycles per degree of visual angle, dva), stimulus sizes (1 to 4 dva) and eccentricities (6 to 10 dva). In each trial, participants executed a saccade to a high-contrast grating presented either left or right of fixation. During the saccade, the grating changed orientation (clockwise or counter-clockwise) either instantaneously or after a 200 ms blank, and participants reported the change's direction. We contrasted this saccade condition with a trans-retinal fixation condition mimicking the peripheral-then-foveal sequence of the target stimulus occurring across a saccade. Remarkably, blanking improved performance reliably for each spatial frequency, stimulus size, and eccentricity, but only in the saccade condition. Performance with blanking in saccade trials systematically exceeded performance in the fixation condition. Our results demonstrate a robust feature blanking effect across saccades, suggesting that transsaccadic processes involve low-level visual features beyond those processed in the magnocellular system.

Wide-angle simulated artificial vision enhances spatial navigation and object interaction in a naturalistic environment

Objective. Vision restoration approaches, such as prosthetics and optogenetics, provide visual perception to blind individuals in clinical settings. Yet their effectiveness in daily life remains a challenge. Stereotyped quantitative tests used in clinical trials often fail to translate into practical, everyday applications. On the one hand, assessing real-life benefits during clinical trials is complicated by environmental complexity, reproducibility issues, and safety concerns. On the other hand, predicting behavioral benefits of restorative therapies in naturalistic environments may be a crucial step before starting clinical trials to minimize patient discomfort and unmet expectations.Approach. To address this, we leverage advancements in virtual reality technology to conduct a fully immersive and ecologically valid task within a physical artificial street environment. As a case study, we assess the impact of the visual field size in simulated artificial vision for common outdoor tasks.Main results. We show that a wide visual angle (45°) enhances participants' ability to navigate and solve tasks more effectively, safely, and efficiently. Moreover, it promotes their learning and generalization capability. Concurrently, it changes the visual exploration behavior and facilitates a more accurate mental representation of the environment. Further increasing the visual angle beyond this value does not yield significant additional improvements in most metrics.Significance. We present a methodology combining augmented reality with a naturalistic environment, enabling participants to perceive the world as patients with retinal implants would and to interact physically with it. Combining augmented reality in naturalistic environments is a valuable framework for low vision and vision restoration research.

Correlation of angle kappa and angle alpha on visual outcomes in eyes implanted with three types of multifocal intraocular lenses.

To evaluate the correlation between preoperative, postoperative, and change in angle kappa and alpha to visual outcomes following implantation of three multifocal intraocular lenses. This is a retrospective study which included 122 eyes of 61 patients. There were 38 eyes in the Synergy (Johnson & Johnson, USA) group and 42 eyes each from both the Panoptix (Alcon Laboratories, USA) and FineVision (Physiol BVI, Belgium) groups. Visual outcome parameters (uncorrected distance, intermediate, near vision, halo and starburst) and angle kappa and alpha were recorded preoperatively and at three months postoperatively. The preoperative, postoperative and the amount of change in angle kappa and alpha were correlated to visual outcomes and photic phenomena among the three different diffractive trifocal IOLs. There were no significant differences in the preoperative and postoperative magnitude of angle kappa and alpha among the Synergy, Panoptix, and FineVision groups. There was no significant correlation between the preoperative and postoperative magnitude, and change in angle kappa and alpha with the postoperative uncorrected distance, intermediate and near visual acuity, and halo and starburst scores of the three different diffractive IOLs. The frequency of eyes with greater than 0.5mm angle kappa and alpha values were low. Visual outcomes can be good even in eyes in which the angle kappa and alpha were greater than 0.5mm. The newer diffractive multifocal IOLs were observed to be more tolerant to low and intermediate levels of angle kappa and alpha.

Comparative visual performance of ultraviolet light-filtering and violet light-filtering monofocal intraocular lenses of the same material and basic design

We compared the visual performance of ZCB00 ultraviolet light-filtering and ZCB00V violet light-filtering monofocal intraocular lenses (IOLs) (both Johnson & Johnson Surgical Vision) with the same materials and basic design in cataract patients treated from 2011 to 2020. The evaluations were performed 10 weeks after the last surgery for implantation of bilateral lenses ≤ 3 months apart. The ZCB00 and ZCB00V groups included 904 eyes from 452 patients (age 72.3 ± 6.8 y; women/men, 268/184) and 1374 eyes from 687 patients (age 73.0 ± 7.4 y; women/men, 415/272), respectively. Statistical validity was confirmed using a linear mixed-effects model with binocular data and adjustments for age, sex, subjective refraction cylinder, subjective refraction spherical equivalent, corneal astigmatism, axial length, pupil diameter, and corneal higher-order aberrations. ZCB00 showed slightly but significantly better results (p < 0.05, Wald) for uncorrected intermediate/near visual acuity, corrected near visual acuity, and components of the 25-item Visual Function Questionnaire (VFQ-25) (Role_Limitation, Mental_Health, Social_Function, Distance_Vision, Color_Vision). Additionally, ZCB00V showed significantly better contrast sensitivity with glare (visual angle of target: 6.3°/4.0°/0.7°; p < 0.00068, Wald); slightly but significantly better contrast sensitivity without glare (4.0°/2.5°/1.6°) and with glare (2.5°/1.6°/1.0°), VFQ-25 General_Health scores, and near spectacle independence; and slightly but significantly smaller higher-order aberrations (internal, scaled to a 6-mm pupil; Wavefront_6_post_I_Trefoil) (p < 0.05, Wald).

Prediction of visual outcomes using virtual implantation of a trifocal intraocular lens in presbyopic lens exchange patients.

To assess the reliability of a novel virtual IOL implantation device to predict the outcomes of a trifocal IOL. Clinical sites in Spain and Germany. Prospective multicenter study. Preoperative measurements obtained by the virtual implantation of AT LISA tri 839MP IOL (Carl Zeiss Meditec AG, Jena, Germany) with VirtIOL device (10Lens S.L.U., Terrassa, Spain) were compared to postoperative (month 3) outcomes following the IOL implantation. Evaluated metrics were defocus curve, contrast sensitivity (both in photopic conditions), and visual phenomena (visual angle size of burst and annular pattern) in mesopic conditions. The study included 45 presbyopic non-cataract patients (mean age 56.16±5.03 years). VirtIOL device reasonably predicted the shape of the defocus curve, especially in the intermediate vision range, but underestimated postoperative visual acuities mainly at the defocus range between +1.0D and -3.5D. The difference between predicted and achieved visual acuity was -0.11±0.13 logMAR (p<0.001) for 0.0D defocus and -0.16±0.15D logMAR (p<0.001) for -2.50D defocus. The shape of the contrast sensitivity curve was almost identical for predicted and achieved measurements, but the device underestimated the values by ≈0.3 logCS units for each spatial frequency. Visual phenomena were similar between the predicted and achieved outcome (predicted vs. achieved: burst pattern 2.65±0.97° vs. 2.74°±0.95°, p=0.63; annular pattern: 0.88±0.42° vs. 0.93±0.49°, p=0.59). The device reasonably predicted the pattern of measured variables. Visual acuity/contrast sensitivity reduction might be attributed to viewing the objects through a more complex optical system and would need to be accounted for in clinical studies.

The impact of camera-monitor system viewing angles on drivers’ distance perception: A simulated driving study

Camera-monitor systems (CMS) are increasingly used in driving. CMS separates the driver's sight line from the camera view, due to the lack of mirror reflection, only changing the camera's visual axis angle may affect the driver's rear view perception. While previous research has explored camera height and field of view, the effects of horizontal and vertical viewing angles alone remain unclear. This study aimed to evaluate how the horizontal viewing angle and vertical viewing angle of CMS camera affect distance estimation and car-following tasks. By changing the horizontal and vertical viewing angle, different self-vehicle references and horizon positions were formed in the image. Two experiments were conducted with the CMS around the steering wheel (Experiment 1) and at the bottom of the A-pillar (Experiment 2). Independent variables were the horizontal viewing angle (reference scale: 1/4, 1/3, 1/2) and vertical viewing angle (horizon position: 1/2, 1/3). Dependent variables included distance estimation error ratio and following distance. Experiment 1 demonstrated a significant interaction effect: a smaller reference scale and higher horizon position reduced distance underestimation. Additionally, a smaller reference scale for the participants' self-vehicle resulted in shorter following distances. In Experiment 2, the distance estimation outcomes on the left display aligned with those of Experiment 1; however, the influence of the viewing angle was diminished on the right display. The study suggests CMS design should balance vehicle reference inclusion with environmental cues, enhancing distance perception and driving safety. The consistency between CMS design and driver familiarity also needs to be considered.

Bifocal system of two reflect arrays

A technique has been developed for accurately solving the problem of geometric-optical synthesis of a bifocal system of two flat reflect arrays, based on the sequential determination of the distribution of the eikonal introduced by different sections of the arrays, with its assignment at the initial section of one of the arrays, while the introduced eikonal at the initial section of the other array is found as a result of synthesis of the output flat front for the central position of the feed. The technique ensures the continuity of functions describing the distributions of introduced eikonals, as well as their first and second derivatives (along one coordinate) at the boundaries of sections. The dependence of the value of the mean square eikonal aberration at the system output on the arrays parameters has been studied. As an example of the application of the developed technique, the bifocal systems for visual angles of 40°and 65°were synthesized and optimized. A study of the radiation characteristics of an antenna based on synthesized and optimized bifocal systems was carried out.

Affordable ultra-widefield smartphone PedCam for comprehensive pediatric retinal examination.

Widefield fundus photography is critical for the detection, documentation, and management of pediatric eye diseases. Existing clinical pediatric fundus cameras offer a limited field of view (FOV) and suboptimal image contrast, hindering comprehensive peripheral retina examination. Additionally, the high cost and lack of portability of commercial devices restrict their use in resource-limited settings. We introduce a cost-effective smartphone-based pediatric camera (PedCam) that provides a 180° eye angle (126° visual angle) snapshot FOV. Utilizing trans-pars planar illumination, the device enables nonmydriatic imaging by allocating the pupil exclusively for imaging, eliminating the need for pharmacological pupillary dilation. By adjusting the optical axis of the PedCam relative to the ocular axis, the effective FOV can be expanded up to 240° eye angle (180° visual angle), enabling complete retinal evaluation. This innovative smartphone PedCam represents a significant advancement in affordable telemedicine for the screening, monitoring, and management of retinopathy of prematurity and other pediatric eye conditions.

BCS-Based Encoding Schemes for Monoview and Multiview Visual Configurations in WVSN Data Gathering: A Survey

Wireless Visual Sensor Network (WVSN) has become a valuable tool in addressing the evolving needs of modern monitoring systems. Encoding in WVSNs is a multifaceted process that involves compressing visual data, optimizing energy consumption, ensuring error resilience, and adapting to various network and application requirements. The associated lightweight encoders and the demand for less storage space make block compressive sensing (BCS) techniques suitable for WVSN applications where energy, bandwidth, and storage resources are limited. Based on the number of visual perspectives or camera angles available within a network for data capture, there are two primary congurations: monoview and multiview. This paper provides a comprehensive survey of dierent BCS-based encoding schemes used for data-gathering in both monoview and multiview scenarios within WVSNs. A comparative study of these algorithms based on compression level, computational complexity, relative gain in encoder energy, and reconstruction quality is performed. A BCS-based joint encoding scheme for multiview conguration that ensures a relatively high compression level is also proposed in this paper.

Perceptual-Cognitive Skills of Basketball Referees: On-The-Court Visual Search Behavior.

Perceptual-cognitive skills are crucial in successfully managing information and decision-making in sports, particularly in high-pressure environments. We examined 16 basketball referees' on-the-court visual search behavior by comparing referees of different experience levels (experienced, n = 8; and novice, n = 8) and different court positions. Participants' visual search behavior was analyzed during 20 live gameplay situations using eye-tracking technology. Dependent variables were the number of eye fixations, mean fixation time, and total fixation time on selected areas of interest; and independent variables were the referees' experience and visual angles (lead and trail referee positions). Experienced referees exhibited significantly lower total fixation time than novice referees (p = .009). Referees in the trail position showed more fixations of shorter duration and a greater focus on the basket than those in the lead position. Our findings suggest that the visual search behavior of basketball referees varies with their court position and experience. These data provide valuable insights into referees' complex visual search patterns in the real-game context, and they highlight the importance of considering viewing angle and experience in future research.

Biometry study of foveal isoplanatic patch variation for adaptive optics retinal imaging.

The change in ocular wavefront aberrations with visual angle determines the isoplanatic patch, defined as the largest field of view over which diffraction-limited retinal imaging can be achieved. Here, we study how the isoplanatic patch at the foveal center varies across 32 schematic eyes, each individualized with optical biometry estimates of corneal and crystalline lens surface topography, assuming a homogeneous refractive index for the crystalline lens. The foveal isoplanatic patches were calculated using real ray tracing through 2, 4, 6 and 8 mm pupil diameters for wavelengths of 400-1200 nm, simulating five adaptive optics (AO) strategies. Three of these strategies, used in flood illumination, point-scanning, and line-scanning ophthalmoscopes, apply the same wavefront correction across the entire field of view, resulting in almost identical isoplanatic patches. Two time-division multiplexing (TDM) strategies are proposed to increase the isoplanatic patch of AO scanning ophthalmoscopes through field-varying wavefront correction. Results revealed substantial variation in isoplanatic patch size across eyes (40-500%), indicating that the field of view in AO ophthalmoscopes should be adjusted for each eye. The median isoplanatic patch size decreases with increasing pupil diameter, coarsely following a power law. No statistically significant correlations were found between isoplanatic patch size and axial length. The foveal isoplanatic patch increases linearly with wavelength, primarily due to its wavelength-dependent definition (wavefront root-mean-squared, RMS <λ/14), rather than aberration chromatism. Additionally, ray tracing reveals that in strongly ametropic eyes, induced aberrations can result in wavefront RMS errors as large as λ/3 for an 8-mm pupil, with implications for wavefront sensing, open-loop ophthalmic AO, spectacle prescription and refractive surgery.

High refresh rate display for natural monocular viewing in AOSLO psychophysics experiments.

By combining an external display operating at 360 frames per second with an adaptive optics scanning laser ophthalmoscope (AOSLO) for human foveal imaging, we demonstrate color stimulus delivery at high spatial and temporal resolution in AOSLO psychophysics experiments. A custom pupil relay enables viewing of the stimulus through a 3-mm effective pupil diameter and provides refractive error correction from -8 to +4 diopters. Performance of the assembled and aligned pupil relay was validated by measuring the wavefront error across the field of view and correction range, and the as-built Strehl ratio was 0.64 or better. High-acuity stimuli were rendered on the external display and imaged through the pupil relay to demonstrate that spatial frequencies up to 54 cycles per degree, corresponding to 20/11 visual acuity, are resolved. The completed external display was then used to render fixation markers across the field of view of the monitor, and a continuous retinal montage spanning 9.4 by 5.4 degrees of visual angle was acquired with the AOSLO. We conducted eye-tracking experiments during free-viewing and high-acuity tasks with polychromatic images presented on the external display. Sub-arcminute eye position uncertainty was achieved over a 1.5 by 1.5-degree trackable range, enabling precise localization of the line of sight on the stimulus while simultaneously imaging the fine structure of the human central fovea. This high refresh rate display overcomes the temporal, spectral, and field of view limitations of AOSLO-based stimulus presentation, enabling natural monocular viewing of stimuli in psychophysics experiments conducted with AOSLO.

Lightweight safflower cluster detection based on YOLOv5

The effective detection of safflower in the field is crucial for implementing automated visual navigation and harvesting systems. Due to the small physical size of safflower clusters, their dense spatial distribution, and the complexity of field scenes, current target detection technologies face several challenges in safflower detection, such as insufficient accuracy and high computational demands. Therefore, this paper introduces an improved safflower target detection model based on YOLOv5, termed Safflower-YOLO (SF-YOLO). This model employs Ghost_conv to replace traditional convolution blocks in the backbone network, significantly enhancing computational efficiency. Furthermore, the CBAM attention mechanism is integrated into the backbone network, and a combined LCIOU+NWD\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$L_{CIOU + NWD}$$\\end{document} loss function is introduced to allow for more precise feature extraction, enhanced adaptive fusion capabilities, and accelerated loss convergence. Anchor boxes, updated through K-means clustering, are used to replace the original anchors, enabling the model to better adapt to the multi-scale information of safflowers in the field. Data augmentation techniques such as Gaussian blur, noise addition, sharpening, and channel shuffling are applied to the dataset to maintain robustness against variations in lighting, noise, and visual angles. Experimental results demonstrate that SF-YOLO surpasses the original YOLOv5s model, with reductions in GFlops and Params from 15.8 to 13.2 G and 7.013 to 5.34 M, respectively, representing decreases of 16.6% and 23.9%. Concurrently, SF-YOLO’s mAP0.5 increases by 1.3%, reaching 95.3%. This work enhances the accuracy of safflower detection in complex agricultural environments, providing a reference for subsequent autonomous visual navigation and automated non-destructive harvesting technologies in safflower operations.

LHFFNet: A hybrid feature fusion method for lane detection

Lane line images have the essential attribute of large-scale variation and complex scene information, and the similarity between adjacent lane lines is high, which can easily cause classification errors. And remote lane lines are difficult to recognize due to visual angle changes in width. To address this issue, this paper proposes an effective lane detection framework, which is a hybrid feature fusion network that enhances multiple spatial features and distinguishes key features throughout the entire lane line segment. It enhances and fuses lane line features at multiscale to enhance the feature representation of lane line images, especially at the far end. Firstly, in order to enhance the correlation of multiscale lane features, a multi-head self attention is used to construct a multi-space attention enhancement module for feature enhancement in multispace. Secondly, a spatial separable convolutional branch is designed for the jumping layer structure connecting multiscale lane line features. While retaining feature information of different scales, important lane areas in multiscale feature information are emphasized through the allocation of spatial attention weights. Finally, considering that lane lines are elongated areas in the image, and the background information in the image is much more abundant than lane line information, the flexibility of traditional pooling operations in capturing widely existing anisotropic contexts in actual environments is limited. Therefore, before embedding feature output branches, strip pooling is introduced to refine the representation of lane line information and optimize model performance. The experimental results show that the accuracy on the TuSimple dataset reaches 96.84%, and the F1 score on the CULane dataset reaches 75.9%.

Interacting with the farthest neighbor promotes cohesion and polarization in collective motion

The collective behavior generated from self-organization is one of the most prominent characteristics of animal populations. Typically, it is assumed that the interactions between individuals are average and synchronous. However, recent empirical studies have shown that interactions between individuals are selective and update their positions and directions asynchronously. Especially the feature factor of distance is widely used in theoretical modeling, but there is no detailed analysis and discussion on it in pairwise interaction. In this work, the effect of pairwise interactions on group motion is investigated under three distance features: nearest, medium, and farthest, based on a self-propelled particle model and combined with an asynchronous update scheme. The research results indicate that simple pairwise interaction can achieve group-level cohesion, especially by selecting the farthest neighbor instead of only interacting with the nearest neighbor, and the proportion of topological neighbors required to achieve cohesion is independent of the group size. In addition, we found that there is a visual angle range that is conducive to achieving cohesion and consistent movement in the group. This study provides insight into selective interaction, especially the great significance of the distance factor in pairwise interaction.

Comparison of endoscopic multiport approaches to the petrous apex: contralateral transmaxillary versus contralateral medial transorbital corridor.

Accessing the petrous apex (PA) via an endoscopic endonasal approach (EEA) is challenging due to its posterior and lateral anatomical relationship with the paraclival carotid artery. Typically, the EEA requires the mobilization or compression of the vessel and the use of angled-lens endoscopes and instruments. A sublabial contralateral transmaxillary (CTM) corridor has been used to overcome these challenges. Still, it requires extensive osteo-meatal disruption and drilling of the medial pterygoid process, which risks the vidian nerve and increases nasal morbidity. Furthermore, the CTM corridor positions the endoscope in the same horizontal plane as the instruments passing through the nostrils, leading to fencing. The authors propose a novel minimally invasive route to the PA, the precaruncular contralateral medial transorbital (cMTO) corridor, to address these issues. This anatomical study compares the EEA+CTM and EEA+cMTO corridors in accessing the PA. The authors dissected 14 fresh, preinjected cadaveric specimens (28 sides) using neuronavigation to complete EEA, cMTO, and CTM on each side. In addition to qualitative analysis, they measured and compared the working distance between the entry point (nose, orbit, maxilla) and the petrosal process of the sphenoid bone (PPSB), superomedial PA, and foramen lacerum (FL); angle of attack (AoA); area of surgical freedom; endoscope-instrument fencing angle; and visual angle for each approach. The cMTO corridor provided the shortest working distance to the petroclival region (PA = 67.4 ± 4.47 mm, PPSB = 67.57 ± 4.33 mm, and FL = 66.30 ± 4.77 mm) compared to the CTM (PA = 75.85 ± 3.63 mm, PPSB = 76 ± 3.96 mm, and FL = 74.52 ± 4.26 mm) and to the EEA (PA = 85.16 ± 3.16 mm, PPSB = 84.55 ± 3.02 mm, and FL = 83.42 ± 3.21 mm, p < 0.001). Both CTM and cMTO corridors had a similar visual angle to the PA (20.72° ± 2.16° and 21.63° ± 1.84°, respectively), offering a similar but significantly better visualization than EEA alone (44.71° ± 3.24°, p < 0.001). The cMTO corridor provided better instrument maneuverability than the CTM, as evidenced by a significantly greater fencing angle (30.9° ± 4.9°) than with the CTM (21.7° ± 4.02°, p < 0.001). The vertical AoAs for the EEA, cMTO, and CTM corridors were 9.79° ± 1.75°, 10.65° ± 0.82°, and 9.82° ± 1.43°, respectively (p = 0.009), whereas in the horizontal plane, these were 9.29° ± 1.51°, 9.10° ± 0.73°, and 10.49° ± 1.43° (p < 0.001), respectively. Both the CTM and cMTO corridors offered similar areas of surgical freedom (678.06 ± 99.5 mm2 and 673.59 ± 104.8 mm2, p = 0.986), but they were more significant than that provided by the EEA 487.29 ± 112.9 mm2 (p < 0.001). The EEA+cMTO multiport technique may be a better alternative than the EEA+CTM multiport approach for targeting the petroclival region. However, clinical validation is required to confirm these laboratory findings.

How interchange spacing effects drivers’ visual performance in high-density interchange groups − a naturalistic driving study

The aim of this study was to evaluate the effects of interchange spacing on the visual characteristics and visual load of drivers in the exit zone of the urban expressway. A naturalistic driving experiment was conducted in a high-density interchange group on the North Ring Expressway in Chongqing, China. Eye-movement data from 47 participants were collected to assess the pattern of visual performance, seven indicators were selected to characterize drivers’ visual characteristics, and the entropy weighting method was used to assess the drivers’ visual loads under different interchange spacing and driving zones. The results show that insufficient spacing of the interchange affects drivers’ visual behavior and increases their visual load level. The fixation duration for drivers is significantly affected by interchange spacing, with longer fixation duration in the diversion and ramp zones of small-spacing interchanging(SSI). The mean horizontal visual angle of drivers was mainly distributed in the middle of the field of view, and there was a tendency for the overall left side to be shifted under the conditions of SSI, and the mean vertical visual angle was mainly distributed in the nearer part in front of the lanes. In the ramp zone of SSI, the driver’s attention to the vehicle dashboard had a significant increase. In normal-spacing interchange(NSI), drivers’ horizontal saccade amplitude and speed were higher than those in SSI, and the difference was most significant in the diversion zone. Vertical saccade amplitude and speed of the driver were found to be significantly affected by interchange spacing only in the ramp zone. Drivers’ visual load had the highest correlation with pupil variation, and the visual load scores of drivers at SSI were 39.65% and 17.7% higher than at NSI in the diversion and ramp zones, respectively. This study provides valuable insights into the effects of the high-density interchange group on the visual performance of drivers on urban expressways, and the results provide a theoretical basis for the spacing control of interchanges.

Head motion-corrected eye gaze tracking with the da Vinci surgical system.

To facilitate the integration of point of gaze (POG) as an input modality for robot-assisted surgery, we introduce a robust head movement compensation gaze tracking system for the da Vinci Surgical System. Previous surgical eye gaze trackers require multiple recalibrations and suffer from accuracy loss when users move from the calibrated position. We investigate whether eye corner detection can reduce gaze estimation error in a robotic surgery context. A polynomial regressor is first used to estimate POG after an 8-point calibration, and then, using another regressor, the POG error from head movement is estimated from the shift in 2D eye corner location. Eye corners are computed by first detecting regions of interest using the You Only Look Once (YOLO) object detector trained on 1600 annotated eye images (open dataset included). Contours are then extracted from the bounding boxes and a derivative-based curvature detector refines the eye corner. Through a user study (n = 24), our corner-contingent head compensation algorithm showed an error reduction in degrees of visual angle of 1.20 (p = 0.037) for the left eye and 1.26 (p = 0.079) for the right compared to the previous gold-standard POG error correction method. In addition, the eye corner pipeline showed a root-mean-squared error of 3.57 (SD = 1.92) pixels in detecting eye corners over 201 annotated frames. We introduce an effective method of using eye corners to correct for eye gaze estimation, enabling the practical acquisition of POG in robotic surgery.