Article History
Received: 7 March 2021
Accepted: 23 August 2021
First Online: 10 September 2021
Competing interests
: The authors declare the following competing interests: F.W., Z.Z., T.H., and C.L. are inventors on the patent application (pending, Ref: 2021-187, serial no. 10202109596U) submitted by National University of Singapore that covers sign language recognition and communication system.