Effect of Automatic Sign Recognition Performance on the Usability of Video-Based Search Interfaces for Sign Language Dictionaries

Researchers have investigated various methods to help users search for the meaning of an unfamiliar word in American Sign Language (ASL). Some are based on sign-recognition technology, e.g. a user performs a word into a webcam and obtains a list of possible matches in the dictionary. However, developers of such technology report the performance of their systems inconsistently, and prior research has not examined the relationship between the performance of search technology and users' subjective judgements for this task. We conducted two studies using a Wizard-of-Oz prototype of a webcam-based ASL dictionary search system to investigate the relationship between the performance of such a system and user judgements. We found that in addition to the position of the desired word in a list of results, which is what is often reported in literature; the similarity of the other words in the results list also affected users' judgements of the system. We also found that metrics that incorporate the precision of the overall list correlated better with users' judgements than did metrics currently reported in prior ASL dictionary research.