Multimedia Tools and Applications
https://doi.org/10.1007/s11042-020-08961-z
Understanding vision-based continuous sign language
recognition
Neena Aloysius
1
· M. Geetha
1
Received: 22 August 2019 / Revised: 13 April 2020 / Accepted: 22 April 2020 /
© Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract
Real-time sign language translation systems, that convert continuous sign sequences to
text/speech, will facilitate communication between the deaf-mute community and the
normal hearing majority. A translation system could be vision-based or sensor-based,
depending on the type of input it receives. To date, most of the commercial systems for
this purpose are sensor-based, which are expensive and not user-friendly. Vision-based sign
translation systems are the need of the hour but should overcome many challenges to build
a full-fledged working system. Preliminary investigations in this work have revealed that
the traditional approaches to continuous sign language recognition (CSLR) using HMM,
CRF and DTW, tried to solve the problem of Isolated Sign Language Recognition (ISLR)
and extended the solution to CSLR, leading to reduced performance. The main challenge
of identifying Movement Epenthesis (ME) segments in continuous utterances, were han-
dled explicitly with these traditional methods. With the advent of technologies like Deep
Learning, more feasible solutions for vision-based CSLR are emerging, which has led to
an increase in the research on vision-based approaches. In this paper, a detailed review
of all the works in vision-based CSLR is presented, based on the methods they have fol-
lowed. The challenges posed in continuous sign recognition are also discussed in detail,
followed by a brief on sensor-based systems and benchmark databases. Finally, perfor-
mance evaluation of all the associated methods are performed, which leads to a short
discussion on the overall study and concludes by pointing out future research directions in
the field.
Keywords Continuous sign language · Vision-based · Movement epenthesis · Review
Neena Aloysius
neenaloysius@ymail.com
M. Geetha
geetham@am.amrita.edu
1
Department of Computer Science and Engineering, Amrita School of Engineering,
Amrita Vishwa Vidyapeetham, Amritapuri, India