Completed

One person looking directly at another person and picking up a cup by the handle, illustrating peripheral stereopsis

Upper Depth Limit Across Visual Field

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Stereopsis is important for tasks of daily living such as eye-hand coordination. It is best in central vision but is also mediated by the periphery. Previously we have shown that individuals with central-field loss who have residual stereopsis in the periphery perform better at an eye-hand-coordination task. Here we sought to determine what sets the limit of stereopsis, defined as the largest disparity that supports the sustained appearance of depth, in the near periphery in healthy individuals.

The dots on the left are moving faster than the dots on the right side of the screen

Motion Perception in Central Field Loss

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The project investigates motion perception in individuals with vision loss due to central retinal lesion, but who retain healthy peripheral retina. Healthy peripheral retina is exquisitely sensitive to fast speeds, however, there is limited and conflicting information about motion processing in residual peripheral retina in patients with central field loss, often due to macular degeneration. We use psychophysical and eye tracking approaches to systematically probe speed and direction sensitivity in this population.

ZoomBoard overview

ZoomBoard: an Affordable, Portable System to Improve Access to Presentations and Lecture Notes for Low Vision Viewers

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The goal of the project is to develop a “ZoomBoard” system that students with low vision can use to better access visual material on a whiteboard or blackboard. The prototype version of the system that we plan to develop in this grant will consist of a dedicated camera system placed by the teacher to capture a view of the board, which wirelessly transmits a video stream that will be displayed on a student’s iPad. The student will use the ZoomBoard app to view this video stream, zoom in on any region of interest using a pinch gesture on the iPad, and apply image enhancements such as contrast…

Graphic of lines of braille with finger trace trajectory superimposed over braille

Regressions in Braille Reading

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This project explores regressions (movements to re-read text) in braille reading. The image on the right plots the braille reading finger movements in blue and regressions in black.

Calibration of Eccentric Power Refractor

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Eccentric power refractors need to be calibrated for accommodation and gaze position for individual participants. Calibration however can be time consuming. We look at different conditions in which calibration is necessary or preferable. This project is now completed. Please see the Publication section for results.

Parafoveal Crowding

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Crowding increases with eccentricity, and is most readily observed in the periphery. During natural, active vision however, central vision plays an important role. Measures of critical distance to estimate crowding are difficult in central vision, as these distances are small. Any overlap of flankers with the target may create an overlay masking confound. The crowding factor method avoids this issue by simultaneously modulating target size and flanker distance and using a ratio to compare crowded to uncrowded conditions. This method was developed and applied in the periphery (Petrov &…

Hands with pen on street map closeup

Audio/Tactile BART Station Maps

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This collaborative project between Smith-Kettlewell and the San Francisco LightHouse applies Smartpen-Based audio/tactile graphics tools to improve orientation and wayfinding by travelers with visual disabilities in and around unfamiliar transit stations.

Sample indoor sign showing automatic detection in yellow

Sign Finder

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This project seeks to develop a computer vision-based system that allows a visually impaired traveler to find and read informational signs, such as signs labeling office doors, streets, restrooms and Exit signs. Link open source code