NSL23 dataset for alphabets of Nepali sign language

Nepali Sign Language (NSL) is used by the Nepali-speaking community in Nepal and in Indian states such as Sikkim, the hilly region of North Bengal, some parts of Uttarakhand, Meghalaya, and Assam. It consists of the International Manual Alphabet (A-Z), Nepali consonants, vowels, conjunct letters, and numbers represented in the form of one-handed fingerspelling or Nepali manual alphabet. The standard gestures for NSL have been published by the Nepal National Federation of the Deaf & Hard of Hearing (NFDH). To learn Nepali Sign Language, the first step is to understand its alphabet set. The use of technology can help ease the learning process. One of the application areas of computer vision is translating sign language gestures to either text or audio to facilitate communication. This is an open research area. However, NSL translation is one of the less explored research areas because there is no dataset available to work on for NSL. This paper introduces the Nepali Sign Language Dataset (NSL23), which is the first of its kind and includes vowels and consonants of the Nepali Sign Language alphabet. The dataset consists of .mov videos performed by 14 volunteers who have demonstrated 36 consonant signs and 13 vowel signs either in one full video or character by character. The dataset has been prepared under various conditions, including normal lighting, dark lighting conditions, prepared environments, unprepared environments, and real-world environments. The volunteers who performed the NSL gesture have been classified as 9 beginners who are using NSL for the first time and 5 experts who have been using NSL for 5 to 25 years. NSL23 contains 630 total videos representing 1205 gestures. The dataset can be used to train machine learning models to classify the alphabet set of NSL and further develop a sign language translator.