Intuitive tactile zooming for graphics accessed by individuals who are blind and visually impaired

Ravi Rastogi, T. V.Dianne Pawluk, Jessica Ketchum

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


One possibility of providing access to visual graphics for those who are visually impaired is to present them tactually: unfortunately, details easily available to vision need to be magnified to be accessible through touch. For this, we propose an 'intuitive' zooming algorithm to solve potential problems with directly applying visual zooming techniques to haptic displays that sense the current location of a user on a virtual diagram with a position sensor and, then, provide the appropriate local information either through force or tactile feedback. Our technique works by determining and then traversing the levels of an object tree hierarchy of a diagram. In this manner, the zoom steps adjust to the content to be viewed, avoid clipping and do not zoom when no object is present. The algorithm was tested using a small, 'mouse-like' display with tactile feedback on pictures representing houses in a community and boats on a lake. We asked the users to answer questions related to details in the pictures. Comparing our technique to linear and logarithmic step zooming, we found a significant increase in the correctness of the responses (odds ratios of 2.64:1 and 2.31:1, respectively) and usability (differences of 36% and 19%, respectively) using our 'intuitive' zooming technique.

Original languageEnglish (US)
Article number6481453
Pages (from-to)655-663
Number of pages9
JournalIEEE Transactions on Neural Systems and Rehabilitation Engineering
Issue number4
StatePublished - 2013
Externally publishedYes


  • Blind and visually impaired
  • haptics
  • visual diagrams
  • zooming

ASJC Scopus subject areas

  • Internal Medicine
  • Neuroscience(all)
  • Biomedical Engineering


Dive into the research topics of 'Intuitive tactile zooming for graphics accessed by individuals who are blind and visually impaired'. Together they form a unique fingerprint.

Cite this