Exploring Parameters of Virtual Character Lighting Through Perceptual Evaluation and Psychophysical Modelling

This thesis explored the parameters of virtual character lighting and their connections to the perceived emotion and appeal of the character. Our main interest is to empirically evaluate various common practices of setting up these parameters in traditional art forms, such as painting, theatre and cinematography, and their psychological effects on the perception of the character according to artistic conventions. We also aimed to standardise a general guideline for lighting design that will enhance the inner states of virtual avatars for maximum audience engagement. We conducted an extensive set of novel psychophysical experiments attempting to assess the links between the physical properties of lighting and the responses of the audience. The results were discussed in relation to theories found in the literature of visual perception, psychology and anthropology. We adapted classic research methodologies such as the multidimensional scaling analysis, the method of constant stimuli and the method of adjustment to the modern research question of how we perceive virtual characters and what makes them engaging for various applications, for example, self-avatars on social media platforms that drew massive interest from professional developers and casual makers alike. Some of our findings agreed and some disagreed with certain codes in cinematic lighting. Based on these newfound insights, we derived a set of lighting guidelines that can be used to enhance the emotion and appeal of digital characters and demonstrated a use case of a perceptual lighting tool. Moreover, our experiment designs, particularly the method of adjustment with real-time graphics, broke new ground for future research in virtual avatars. In summary, our contributions found applications in both industry practice and academic research