Gordon E. Legge - US grants

We will measure how reading by observers with normal and low vision depends on the stimulus properties of text. The stimulus properties of text that are necessary for normal observers to read are defined to be the visual requirements of reading. Our research has three primary goals: 1) to measure the visual requirements of reading under conditions that are relevant to low vision; 2) to develop simple tests of visual capacity that can predict reading performance of low-vision observers; and 3) to discover the influence on reading performance of stimulus properties, opthalmic disorder, acuity deficit and field loss for low-vision observers. We will use psychophusical methods in five series of exerpiments. First we will discover the visual requirements of normal reading, with special emphasis on contract and spatial frequency. We will also measure the visual requirements of letter, word, and picture recognition. Secondly, we will seek to develop improved means for measuring contrast sensitivity, based on recognition rather than detection, to quantify the visual capacityes of low-vision observers. Thirdly, we will determine whether recognition tests of contrast sensitivity and knowledge of the visual requirements of normal reading can be used together to predict reading performance of low-vision observers. Fourthly, we will measure effects of several special factors of low-vision reading--glare, contrast reversal, wavelength, and defocus. Finally, we will test hyptheses that attempt to explain psychphysical properties of reading in terms of known properties of pattern vision. The research will be useful in three ways: 1) improved uonderstanding of the sensory constrains of normal reading; 2) the development of systematic techniques for testing low-vision capacity, with the aim of specifying image properties required of an appropriate reading aid; and 3) in establishing necessary stimulusl characteristics for new low-vision reading aids.

Contrast plays a crucial role in pattern vision. Loss of contrast hampers vision in may ways. This proposal deals with the influence of suprathreshold contrast in human vision. The research has three main purposes: to study the spatial properties of visual mechanisms that code contrast, to use what we have learned about contrast coding to enhance images for people with low vision, and to link work on the sensory coding of contrast to perceptual processes of object recognition. We will use psychophysical and image processing methods in four series of experiments. In the first, we will use a new "yoked-contrast" procedure to distinguish between two models of contrast coding. In the second series, we will use a new variant of the simultaneous detection/identification paradigm to study spatial-frequency and orientational selectivity as a function of contrast. In the third series, we will apply principles of contrast coding to the design of image-enhancement algorithms based on gray-scale histogram flattening. We are particularly interested in the potential value of such techniques for those people with low vision who suffer from attenuated retinal contrast (e.g. cataract) or reduced contrast sensitivity (e.g. central-field loss). In the fourth series, we will use the concept of an "ideal observer" from signal-detection theory to measure how efficiently subjects code and use stimulus information to understanding the difficulties experienced by people with low vision on object recognition.

We will measure how reading by observers with normal and low vision depends on the stimulus properties of text. The stimulus properties of text that are necessary for normal observers to read are defined to be the visual requirements of reading. Our research has three primary goals: 1) to measure the visual requirements of reading under conditions that are relevant to low vision; 2) to develop simple tests of visual capacity that can predict reading performance of low-vision observers; and 3) to discover the influence on reading performance of stimulus properties, opthalmic disorder, acuity deficit and field loss for low-vision observers. We will use psychophusical methods in five series of exerpiments. First we will discover the visual requirements of normal reading, with special emphasis on contract and spatial frequency. We will also measure the visual requirements of letter, word, and picture recognition. Secondly, we will seek to develop improved means for measuring contrast sensitivity, based on recognition rather than detection, to quantify the visual capacityes of low-vision observers. Thirdly, we will determine whether recognition tests of contrast sensitivity and knowledge of the visual requirements of normal reading can be used together to predict reading performance of low-vision observers. Fourthly, we will measure effects of several special factors of low-vision reading--glare, contrast reversal, wavelength, and defocus. Finally, we will test hyptheses that attempt to explain psychphysical properties of reading in terms of known properties of pattern vision. The research will be useful in three ways: 1) improved uonderstanding of the sensory constrains of normal reading; 2) the development of systematic techniques for testing low-vision capacity, with the aim of specifying image properties required of an appropriate reading aid; and 3) in establishing necessary stimulusl characteristics for new low-vision reading aids.

We will measure how reading by observers with normal and low vision depends on the stimulus properties of text. The stimulus properties of text that are necessary for normal observers to read are defined to be the visual requirements of reading. Our research has three primary goals: 1) to measure the visual requirements of reading under conditions that are relevant to low vision; 2) to develop simple tests of visual capacity that can predict reading performance of low-vision observers; and 3) to discover the influence on reading performance of stimulus properties, opthalmic disorder, acuity deficit and field loss for low-vision observers. We will use psychophusical methods in five series of exerpiments. First we will discover the visual requirements of normal reading, with special emphasis on contract and spatial frequency. We will also measure the visual requirements of letter, word, and picture recognition. Secondly, we will seek to develop improved means for measuring contrast sensitivity, based on recognition rather than detection, to quantify the visual capacityes of low-vision observers. Thirdly, we will determine whether recognition tests of contrast sensitivity and knowledge of the visual requirements of normal reading can be used together to predict reading performance of low-vision observers. Fourthly, we will measure effects of several special factors of low-vision reading--glare, contrast reversal, wavelength, and defocus. Finally, we will test hyptheses that attempt to explain psychphysical properties of reading in terms of known properties of pattern vision. The research will be useful in three ways: 1) improved uonderstanding of the sensory constrains of normal reading; 2) the development of systematic techniques for testing low-vision capacity, with the aim of specifying image properties required of an appropriate reading aid; and 3) in establishing necessary stimulusl characteristics for new low-vision reading aids.

Contrast plays a crucial role in pattern vision. Loss of contrast hampers vision in may ways. This proposal deals with the influence of suprathreshold contrast in human vision. The research has three main purposes: to study the spatial properties of visual mechanisms that code contrast, to use what we have learned about contrast coding to enhance images for people with low vision, and to link work on the sensory coding of contrast to perceptual processes of object recognition. We will use psychophysical and image processing methods in four series of experiments. In the first, we will use a new "yoked-contrast" procedure to distinguish between two models of contrast coding. In the second series, we will use a new variant of the simultaneous detection/identification paradigm to study spatial-frequency and orientational selectivity as a function of contrast. In the third series, we will apply principles of contrast coding to the design of image-enhancement algorithms based on gray-scale histogram flattening. We are particularly interested in the potential value of such techniques for those people with low vision who suffer from attenuated retinal contrast (e.g. cataract) or reduced contrast sensitivity (e.g. central-field loss). In the fourth series, we will use the concept of an "ideal observer" from signal-detection theory to measure how efficiently subjects code and use stimulus information to understanding the difficulties experienced by people with low vision on object recognition.

Human and other primates have the remarkable ability to use vision to program and control skilled movements directed at objects in their environment. Understanding the processes and representations underlying these skills is a central problem in cognitive science. We propose to develop a focused program for graduate research training in the area of visual perception and motor control. In so doing, we will capitalize on the University of Minnesota's impressive faculty strength in this area. Students in the program will be co-advised by two of the 14 participating faculty, representing behavioral, computational and neuroscience approaches. Students will learn about these three approaches through a required distribution of classes and interdisciplinary seminars. Students will have the opportunity to spend a summer in research at a leading university of industry laboratory that specializes in vision and motor control. The program will form a new topical focus within the Center for research in Leaning, Perception and Cognition. The Center has an excellent record for attracting top students and for supervising them to completion of the Ph.D. The Center is also active in recruiting minority students. Our proposed NSF program will build on the infrastructure already available through the Center.

DESCRIPTION: The first series of experiments seeks to provide data on the role of color in segmentation. The second series of experiments investigates whether illusory contours can add to real contours by adding a contrast edge in the region of an illusory contour and looks at the effect of the illusory contour on its detectability. The third series of experiments investigates how shadows influence judgements of shape and object recognition. The final series of experiments seeks to understand 'object invariance.'

DESCRIPTION (Taken from the applicant's Abstract):There are 3.5 million Americans with low vision. Many have daily problems navigating and recognizing objects around them. These problems can threaten personal independence and quality of life. There has been almost no research on low-vision object recognition or navigation. Theoretical and experimental studies in this proposal have the broad goal of understanding and ameliorating these problems. Most people with low vision contend with either visual-field loss or field restriction form magnifiers. As a result, viewing of objects or environments often requires a piecemeal search of the scene for informative details. People with normal vision use eye movements to explore scenes, especially when visibility is poor. The major theoretical goal is to develop a conceptual framework for describing visual exploration of objects and environments. We will develop Active ideal-observer models of object recognition and navigation. These models will perform optimally in a given visual task, and will serve as benchmarks for interpreting the performance of people with normal and low vision. One of the experimental goals is to study eye-movement exploration and magnifier exploration to recognize objects. What visual features and cognitive strategies guide this exploration? A second experimental goal is to determine whether training on cognitive maps can be a useful navigation aid for people with low vision. (Cognitive maps are memory representations of visual and spatial information about environments.) The team will perform psychophysical experiments in virtual and real buildings. The long-term goal is to develop a computer-based method for imparting information about building layouts to visually disabled people. In this grant, the team will study the impact of impaired vision, esp. field loss, on the formation and use of cognitive maps. Their hypothesis is that cognitive maps, although difficult to learn with visual impairment, will be esp. beneficial to people with low vision.

[unreadable] DESCRIPTION (provided by applicant): [unreadable] This is an application for five years of support for an interdisciplinary training program in cognitive science. The program will integrate biological and behavioral approaches in three focused research domains of greatest strength at the University of Minnesota--perception and action, learning and memory, and emotion and affect. These topics are currently among the most active areas in cognitive science, and all have direct application to human health. Future major advances in these areas are likely to come from researchers who have expertise bridging multiple approaches, thus motivating our plans to provide interdisciplinary training. [unreadable] [unreadable] Each year, the program will train 12 predoctoral and 3 postdoctoral students. Trainees, specializing in one of the three research domains, will receive advanced training in at least two of four major approaches-developmental, behavioral, neurobiological, and computational--and will have co-advisors representing at least two of these approaches. Features of the training program ensuring interdisciplinary breadth include multiple laboratory exposure, weekly multidisciplinary colloquia, journal clubs and seminars, travel to conferences, instruction in the responsible conduct of research, and an annual research symposium. Ultimately, our goal is to provide a multi-lab, and multi-advisor experience that will allow our trainees to move fluidly among topics, instrumentation, and advanced methods, to address challenging problems in cognitive science and human mental health. [unreadable] [unreadable] The training program will be administered through the Center for Cognitive Sciences (CCS), an interdisciplinary, inter-departmental unit with an existing infrastructure of facilities and programs geared to graduate training. The 26 preceptors from nine departments all have strong training and research credentials, and all have active, major laboratories. The Center has the unique opportunity to develop a training program with faculty expertise capable of interweaving our three research domains and four cross-cutting approaches. An important feature of the training program is the strong representation of faculty with interests in translational research. [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Reduced mobility is one of the most debilitating consequences of vision loss for more than three million Americans with low vision. We define visual accessibility as the use of vision to travel efficiently and safely through an environment, o perceive the spatial layout of key features in the environment, and to keep track of one's location in the environment. Our goal is to create tools to enable the design of safe environments for the mobility of low-vision individuals, including those with physical disabilities and to enhance safety for older people and others who may need to operate under low lighting and other visually challenging conditions. We plan to develop a computer-based design tool enabling architectural design professionals to assess the visual accessibility of a wide range of environments (such as a hotel lobby, subway station, or eye-clinic reception area). This tool will simulate such environments with sufficient accuracy to predict the visibility of key landmarks or hazards, such as steps or benches, for different levels and types of low vision, and for spaces varying in lighting, surface properties and geometric arrangement. Our project addresses one of the National Eye Institute's program objectives: Develop a knowledge base of design requirements for architectural structures, open spaces, and parks and the devices necessary for optimizing the execution of navigation and other everyday tasks by people with visual impairments. Our research plan has three specific goals: 1) Empirical: determine factors that influence low-vision accessibility related to hazard detection and navigation in real-world spaces. 2) Computational: develop working models to predict low vision visibility and navigability in real-world spaces. 3) Deployment: translate findings from basic vision science and clinical low vision into much needed industrial usage by producing a set of open source software modules to enhance architectural and lighting design for visual accessibility. The key scientific personnel in our partnership come from three institutions: University of Minnesota -- Gordon Legge and Daniel Kersten; University of Utah -- William Thompson and Sarah Creem-Regehr; and Indiana University -- Robert Shakespeare. This interdisciplinary team has expertise in the necessary areas required for programmatic research on visual accessibility -- empirical studies of normal and low vision (Legge, Kersten, Creem-Regehr, and Thompson), computational modeling of perception (Legge, Kersten, and Thompson), computer graphics and photometrically accurate rendering (Thompson & Shakespeare) and architectural lighting design (Shakespeare). We have collaborative arrangements with additional architectural design professionals who will participate in the translation of our research and development into practice.

DESCRIPTION (provided by applicant): Psychophysics of Reading - Normal and Low Vision Abstract Reading difficulty is one of the most disabling consequences of vision loss for five million Americans with low vision. Difficulty in accessing print imposes obstacles to education, employment, social interaction and recreation. The ongoing transition to the production and distribution of digital documents brings about new opportunities for people with visual impairment. Digital documents on computers and mobile devices permit easy manipulation of print size, contrast polarity, font, page layout and other attributes of text. In short, we now hae unprecedented opportunities to adapt text format to meet the needs of visually impaired readers. In recent years, our laboratory and others in the vision-science community have made major strides in understanding the impact of different forms of low vision on reading, and the dependence of reading performance on key text properties such as character size and contrast. But innovations in reading technology have outstripped our knowledge about low-vision reading. A major gap still exists in translating these laboratory findings into methods for customizing text displays for people with low vision. The broad aim of the current proposal is to apply our knowledge about the impact of vision impairment on reading to provide tools and methods for enhancing reading accessibility in the modern world of digital reading technology. Our research plan has three specific goals: 1) To develop and validate an electronic version of the MNREAD test of reading vision, to extend this technology to important text variables in addition to print size, and to develop methods for customizing the selection of text properties for low-vision readers. MNREAD is the most widely used test of reading in vision research and was originally developed in our laboratory with NIH support. 2) To investigate the ecology of low-vision reading in order to better understand how modern technologies, such as iPad and Kindle are being used by people with low vision. We plan to evaluate the feasibility of using internet methods to survey low-vision individuals concerning their reading behavior and goals, and of collecting approximate measures of visual function over the internet. We also plan to develop an accessibility checker to help low-vision computer users and their families to evaluate the accessibility of specific text displays. 3) To enhance reading accessibility by developing methods for enlarging the visual span (the number of adjacent letters that can be recognized without moving the eyes). A reduced visual span is thought to be a major factor limiting reading in low vision, especially for people with central-field loss from macular degeneration. We have already demonstrated methods for enlarging the visual span in peripheral vision. We plan to develop a more effective perceptual training method for enlarging the visual span, with the goal of improving reading performance for people with central-vision loss.

The human senses provide the information to the brain about the world around us. Deficits in visual, auditory or other sensory inputs have a major impact on quality of life, including education, employment and social engagement, which in turn places a major burden on the US economy. The scale of this problem is large: According to reports by the World Health Organization (WHO) and the National Institutes of Health, there are approximately 5 million Americans with vision impairment and around 36 million Americans with some form of hearing loss. There is broad recognition of the need for interdisciplinary collaboration for translational research on disabilities. Research into the development of more effective assistive technologies and environmental modifications requires interdisciplinary expertise that unites a fundamental understanding of the basic sensory science (vision, audition, motor control, speech and language) with deep technical expertise in engineering, computer science, and other related fields. This National Science Foundation Research Traineeship (NRT) award to the University of Minnesota will enable the formation of an integrated and interdisciplinary training program in sensory science through the joint strengths of the university's Center for Cognitive Sciences and Center for Applied and Translational Sensory Science. The program's goal is to prepare future scientists to combine engineering approaches with scientific knowledge and methods so that they are in a position to develop the next generation of sensory aids that will improve the quality of life for Americans with sensory loss. The program will serve students from computer science, engineering, kinesiology, psychology, and speech-language-hearing disciplines through courses, research opportunities, internships in the medical-devices industry, and public outreach activities. A total of 49 different PhD students will be enrolled in the program over the course of the 5 years, 18 of whom will receive NRT fellowships.

This project creates a new interdisciplinary graduate training program that encompasses the following key aims: 1. Establish an academic program in the form of a graduate minor through which students will receive the focused, multi-disciplinary educational background they will need to address critical challenges in the development of assistive technologies for sensory loss. 2. Advance interdisciplinary research in translational sensory science through the development of structural mechanisms that support the formation of interdisciplinary research teams. 3. Provide extra-curricular training and networking opportunities to the trainees through supplementary mechanisms, including weekly journal clubs, summer and winter workshops, spring and fall research symposia, and an annual fall retreat. Students will also participate in public engagement such as preparation of podcasts on research topics of interest to the stakeholders. 4. Provide practical career development opportunities through personalized contacts with local and national companies. Many trainees will eventually seek employment in industry, and those who continue in academia should seek to engage in collaborative work with industry partners. In an effort to provide students with real-world experience that can inform their research and post-graduation career choices, the program will offer the trainees 8-10 week summer internship opportunities in industry-based applied research.

The NSF Research Traineeship (NRT) Program is designed to encourage the development and implementation of bold, new potentially transformative models for STEM graduate education training. The Traineeship Track is dedicated to effective training of STEM graduate students in high priority interdisciplinary research areas, through comprehensive traineeship models that are innovative, evidence-based, and aligned with changing workforce and research needs.

Project Summary Age-related macular degeneration (AMD) typically produces extensive central vision loss, leading to difficulty in reading, navigating, and other critical tasks. Current assistive devices for vision with central scotomas, while promising, are limited in effectiveness. This proposal aims to fill this gap by advancing understanding of remapping, a method that improves the effectiveness of patients? residual vision by shifting information from inside the central blind spot (scotoma) to intact locations in the visual field. Only a handful of past studies have examined remapping, including just a single study of patients. Our group recently demonstrated the method?s promise, showing that it can improve reading substantially in observers with simulated field loss. Critically, patients differ widely in the shape of their scotomas, and the quality of their vision across the visual field. This variability imposes severe limitations on the ?one size fits all? remapping approaches used in prior work, that simply shift the image away from the scotoma center. If, for example, a patient?s preferred retinal location (used for high acuity tasks) is near the lower left edge of their scotoma, shifting text upward or rightward may not aid reading as much as shifting it downward, as the latter will place the text in regions of best visual acuity. This proposal will test the value of personalized remappings, which shift the image in a way that is optimized for each patient?s residual vision. The remappings are constructed using a novel letter recognition perimetry task, which measures performance across the visual field: The personalized remappings are constructed to shift text to maximize observers? total letter recognition ability. Proposed work will first test the hypothesis that personalized remapping can improve single word recognition. Single word reading will be measured with a variety of scotoma sizes, shapes, and PRL locations. Performance with personalized remapping will be compared to that with traditional remapping and no remapping in both control observers with simulated scotomas and people with macular degeneration. Proposed work will also test the hypothesis that personalized remappings can improve free reading. Reading speed, error rates, and eye movement patterns will be measured in a sentence reading task, and in free reading of natural images containing text. Preliminary data support the value of remapping generally, and the potential of the letter recognition perimetry task for building personalized remappings. Results of this proposal will provide the first thorough testing of remapping, and will also inform models of peripheral reading in patients and controls. The proposed studies will develop and evaluate a novel method for assisting people with low-visions, tailored to their individual residual performance. Personlaized remapping may also be incorporated into practical visual aids to improve daily visual function and quality of life.