New PhD Study Enhances Assistive Technology for the Visually Impaired

[Article by Nane Zietsman]

The Faculty would like to congratulate Rynhardt Kruger on successfully defending his PhD: Technical Document Accessibility. Kruger conducted his PhD under Professors Thomas Niesler and Febe de Wet, both at the Digital Signal Processing (DSP) Research Group in the Department of Electrical and Electronic Engineering. His research developed methods that allow blind or visually impaired people to access mathematical content, such as equations, in PDF documents. “Technical diagrams and equations remain largely inaccessible to blind and visually impaired readers because they are predominantly published as untagged PDFs, which do not include the semantic data necessary to be read by a screen reader. In addition, when equations are available in an accessible format, they must be read in a linear fashion since this is how mathematics is expressed in current accessible formats. This hinders blind readers from accessing the visual layout of the equation,” explains Kruger.

His methods address these challenges by enabling blind and visually impaired readers to systematically examine a figure or an equation through sound as well as gestures on a touch screen, and by text-based navigation. Kruger adds that this solution makes the two-dimensional layout of equations accessible, which can provide valuable additional information to a blind reader. When applied, equations are set out as a network of ‘rooms’, interconnected according to the geometric layout of the equation. The reader can examine the equation by ‘walking’ from room to room and investigating the different components. This is sometimes achieved by using synthetic speech, for example with symbols such as ‘x’ and ‘=’. Alternatively, readers can listen to a sound image that describes graphical elements, such as different types of parentheses and root signs. Kruger has recorded the following video demonstrating this function:

Importantly, these methods offer an affordable solution to users since they can be implemented on ordinary computer hardware, such as a tablet.

Kruger credits many of his research insights to his experiences as a blind scholar in STEM, which provided him with intuitive knowledge about the kind of solution that would be useful. He was born with Leber congenital amaurosis (LCA), a rare inherited retinal disease characterised by severely impaired vision or blindness at birth. His academic journey started in 2009, when he joined Stellenbosch University to pursue a Bachelor of Science (BSc). Kruger proceeded to obtain Honours and Master’s degrees in Computer Science, becoming the first blind person at Stellenbosch University to obtain postgraduate degrees in this field.

Commenting on the significance of his work, Kruger believes that academia can benefit from the unique perspectives of people with different life experiences. “I think people with disabilities can make valuable contributions to academic conversations. As technology progresses, the possibility of pursuing further studies, like a PhD, will increase for people in our disabled communities who are often faced with barriers when it comes to access. It is exciting to think that we can play a part in changing the narrative for future scholars,” concludes Kruger.

Photograph: Rynhardt Kruger during a hike in the Oribi Gorge in Kwa-Zulu Natal.