Implementing chroma key compositing with a green screen to improve the learning experience of remote students during synchronous hybrid lectures

The synchronous hybrid learning model, which involves simultaneous face-to-face and remote learning, suffers from a disparity in the lesson experience and outcomes provided by the different learning modes. Moreover, the online medium allows little opportunity for teachers to exhibit non-verbal immediacy behaviours to improve cognitive engagement and motivation to learn in remote students, further exacerbating the disparity. This work describes the implementation of chroma key compositing that livestreamed weatherman style composite videos to remote students over the online medium during hybrid lessons at a lecture hall. A green screen was used to perform background removal and the teacher was digitally inserted in front of the course content in real time, visually mimicking classroom teaching for remote students, without requiring an on-site camera crew. This work also presents an implementation mode that unifies the view of both face-to-face and remote students. Aggregate results of student surveys indicate that more than 80% of remote students perceived significant improvement in visibility of lecture delivery, teacher presence and capture of attention, while 91% of face-to-face respondents indicated that their in-person learning experience was not significantly affected. Categorical data analysis on itemised responses indicates that students who only adopted the remote learning mode have at least a 90% likelihood of moderately or strongly favouring the setup and implementation. As a whole, our results indicate strong evidence that our setup and implementation has significantly reduced the disparity in learning experiences.