Querying a sign language dictionary with videos using dense vector search

Abstract

To search for an unknown sign in a sign language dictionary, users typically indicate parameters of the query, e.g., hand shape and signing location. Recent advances in sign language recognition enable video-based sign language dictionary search. In such a system, users can record an unknown sign and retrieve a list of signs that look similar, preferably including the queried sign as one of the top results. We have realized such a system by interpreting it as a dense vector search task. First, we learn a mapping (embedding) from sign videos to a vector space. The dictionary can then be searched by looking for the vectors in this space that are closest to the vector corresponding to the query. We present a proof of concept on a subset of the Flemish Sign Language dictionary. Further research is required to scale up our method to the large vocabularies of entire dictionaries.