Astigmatism and Pseudoaccommodation in Pseudophakic Eyes

noAdvanced IOLs with circumferential zones of different power provide pseudoaccommodation. We investigated the potential for power variation with meridian, namely astigmatism, to provide pseudo-accommodation. With appropriate power and axis orientations, acceptable pseudo-accommodation can be achieved

Using Image Sequences for Long-Term Visual Localization

Estimating the pose of a camera in a known scene, i.e., visual localization, is a core task for applications such as self-driving cars. In many scenarios, image sequences are available and existing work on combining single-image localization with odometry offers to unlock their potential for improving localization performance. Still, the largest part of the literature focuses on single-image localization and ignores the availability of sequence data. The goal of this paper is to demonstrate the potential of image sequences in challenging scenarios, e.g., under day-night or seasonal changes. Combining ideas from the literature, we describe a sequence-based localization pipeline that combines odometry with both a coarse and a fine localization module. Experiments on long-term localization datasets show that combining single-image global localization against a prebuilt map with a visual odometry / SLAM pipeline improves performance to a level where the extended CMU Seasons dataset can be considered solved. We show that SIFT features can perform on par with modern state-of-the-art features in our framework, despite being much weaker and a magnitude faster to compute. Our code is publicly available at github.com/rulllars

Perceptual image quality assessment for various viewing conditions and display systems

From complete darkness to direct sunlight, real-world dis- plays operate in various viewing conditions often resulting in a non-optimal viewing experience. Most existing Image Quality Assessment (IQA) methods, however, assume ideal environments and displays, and thus cannot be used when viewing conditions differ from the standard. In this paper, we investigate the influence of ambient illumination level and display luminance on human perception of image quality. We conduct a psychophysical study to collect a novel dataset of over 10000 image quality preference judgments performed in illumination conditions ranging from 0 lux to 20000 lux. We also propose a perceptual IQA framework that allows most existing image quality metrics (IQM) to accurately predict image quality for a wide range of illumination conditions and display parameters 1 . Our analysis demonstrates strong cor- relation between human IQA and the predictions of our proposed framework combined with multiple prominent IQMs and across a wide range of luminance values

Ocular higher-order aberrations and visual performance

Since adaptive optics was first used to correct the monochromatic aberrations of the eye over a decade ago there has been considerable interest in correcting the ocular aberrations beyond defocus and astigmatism. In order to understand the prospective benefits of correcting these higher-order aberrations it is important to study their effect on visual performance. From a clinical perspective it is important to know how different types of aberration can affect visual performance so that wavefront measurements can be better understood. Visual performance is determined by a combination of optical and neural factors. It is important to consider how degradations in the optical quality of the eye can impact the neural processes involved in visual tasks such as object recognition. In this thesis we present a study of the effects of three types of aberration, defocus, coma and secondary astigmatism, on letter recognition and reading performance. In the course of this work we also characterise the repeatability of the Zywave aberrometer, which we used to measure our subjects' ocular wavefronts. We use stimuli that have these aberrations applied in their rendering to examine the differences between these aberrations and how they differ with respect to the visual task. We find that secondary astigmatism causes the largest impairment to both letter recognition and reading performance, followed by defocus. Coma causes comparatively smaller degradations to performance but its effect is different depending on the visual task. We can predict the reduction in performance based on a simple cross-correlation model of letter confusability. The relationship between these predictions and the experimental results are the same for all three aberrations, in the case of single letter recognition. In reading however, the relationship is different for coma. We suggest that coma causes lateral masking effects and may additionally disrupt the planning of eye movements. Coma slows reading, but does not specifically impair word identification whereas defocus and secondary astigmatism do. We attribute disruptions in word identification to the dramatic effects defocus and secondary astigmatism have on the form of a letter

A practical guide and software for analysing pairwise comparison experiments

Most popular strategies to capture subjective judgments from humans involve the construction of a unidimensional relative measurement scale, representing order preferences or judgments about a set of objects or conditions. This information is generally captured by means of direct scoring, either in the form of a Likert or cardinal scale, or by comparative judgments in pairs or sets. In this sense, the use of pairwise comparisons is becoming increasingly popular because of the simplicity of this experimental procedure. However, this strategy requires non-trivial data analysis to aggregate the comparison ranks into a quality scale and analyse the results, in order to take full advantage of the collected data. This paper explains the process of translating pairwise comparison data into a measurement scale, discusses the benefits and limitations of such scaling methods and introduces a publicly available software in Matlab. We improve on existing scaling methods by introducing outlier analysis, providing methods for computing confidence intervals and statistical testing and introducing a prior, which reduces estimation error when the number of observers is low. Most of our examples focus on image quality assessment.Comment: Code available at https://github.com/mantiuk/pwcm

Biologically Inspired Processing for Lighting Robust Face Recognition

ISBN 978-953-307-489-4, Hard cover, 314 pagesNo abstrac

The Effects of Active Luminous Road Markings Solutions on Simulated Driving Performance: an Experimental Study

openDriving at night or in hazardous weather could be risky if artificial lighting is inadequate or insufficient, especially when engaging curves. Innovative solutions, like Active Luminous Road Markings (ALRMs), might assist drivers and improve road safety. However, international road regulations lack consistent guidelines for ALRMs’ lighting colors and designs. We assessed different ALRMs solutions on 27 young adult drivers negotiating curves in simulated scenarios. We manipulated ALRMs appearance (color: green, red, and unlit), size (width: conventional and wide), and road geometry (curve direction: left and right and radius: 120m and 440m). After the driving simulation, participants completed a video-based perception task rating their perceived levels of risk, speed estimation, valence and arousal. The lateral position was significantly affected by ALRMs features, resulting in changes in the driving trajectory toward the right side of the vehicle’s lane in response to color, width, and curve radius. Green ALRMs showed higher variability for vehicle position, indicating reduced vehicle control. Curve radii also affected driving behavior, with narrower curves leading to reduced speeds. Subjective measures revealed that green ALRMs were perceived as brighter but less comfortable. Furthermore, curve radius significantly influenced arousal and speed estimates, with narrower curves eliciting lower activation and slower speed perception. Our study might offer valuable information that transportation engineers, road designers, and transportation psychologists can use to implement smart road technologies and improve road safety when designing new traffic lighting solutions

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 183

This bibliography lists 273 reports, articles, and other documents introduced into the NASA scientific and technical information system in July 1978

Characteristics of flight simulator visual systems

The physical parameters of the flight simulator visual system that characterize the system and determine its fidelity are identified and defined. The characteristics of visual simulation systems are discussed in terms of the basic categories of spatial, energy, and temporal properties corresponding to the three fundamental quantities of length, mass, and time. Each of these parameters are further addressed in relation to its effect, its appropriate units or descriptors, methods of measurement, and its use or importance to image quality