# Camera-Sourced Heart Rate Synchronicity: A Measure of Immersion in Audiovisual Experiences
## 6 Conclusions  
A camera-sourced ISC-HR feature, quantifying the similarity of each participant's heart rate with all other participants in terms of _minute-by-minute_ changes, was found to have a statistically significant correlation with responses to a post-experience immersion questionnaire once two significant outliers were removed. Moreover, the accuracy of this camera-sourced ISC-HR feature was confirmed using an equivalent ground-truth feature obtained from an ECG signal. Based on these results, we conclude that camera-sourced heart rate synchronicity is a viable means of indexing immersion for our chosen stimuli. This is a novel method and a distinct research contribution. Considering the existing research that utilises similar ISC-HR features acquired using an ECG sensor, we expect that the measure may also generalise to other audiovisual stimuli. However, there are concerns regarding the robustness of the camera-based approach to dark-skinned individuals, different cameras, and preferable darker viewing conditions. To confirm these assertions, further research is required. The results of the study suggest that audio presentation alone may not be capable of changing a spectator's feeling of immersion during a film-viewing experience. This is considered to be a research contribution. We now consider that the experiential value of new audio technologies is overstated in this context. In the future, alternative stimuli and a larger sample size should be applied to empirically confirm or deny the hypothetical positive experiential outcomes associated with high-end audio presentation. When discussing the results of future research efforts, we suggest consider how the specific media translates between playback scenarios. Our research should also be supplemented with more exploratory analysis, considering the difference between the two groups and the relationship between alternative physiological features and the self-report scores, using the dataset from this study, which is available upon request. Notably, work should be conducted to explore the ECG data, which are only considered here as a ground truth for comparison with the camera-measured feature. To process these data, the GitHub repository associated with this manuscript should be utilised [67]. Conceptualisation, [PERSON], [PERSON] and J.F. ; methodology, [PERSON], D.M. and J.F. ; software, [PERSON]; validation, [PERSON]; formal analysis, [PERSON]; investigation, [PERSON]; resources, [PERSON]; data curation, [PERSON]; writing--original draft preparation, [PERSON]; writing--review and editing, [PERSON], D.M. and J.F. ; visualisation, [PERSON]; supervision, [PERSON] and J.F. ; project administration, [PERSON] and J.F. ; funding acquisition, [PERSON] All authors have read and agreed to the published version of the manuscript. This work is supported in part by the UK Arts and Humanities Research Council (AHRC) XR Stories Creative Industries Cluster project, grant no. AH/S002839/1; and in part by a University of York-funded PhD studentship, with additional support from Bang & Olufsen. This study was conducted in accordance with the Declaration of Helsinki and approved by the University of York School of Physics, Technology & Engineering ethics committee (protocol code: Williams20230406, date of approval: 25 April 2023). Informed Consent Statement: Informed consent was obtained from all subjects involved in the study. A dataset containing skin segments extracted from the video footage, ECG data, and immersion questionnaire results is available upon request; please email [PERSON] ([EMAIL_ADDRESS]) and [PERSON] ([EMAIL_ADDRESS]). A code repository associated with this publication is publicly available on GitHub [67]. The authors would like to thank [PERSON] for his support in discussing the analytic methods applied in this paper. Acknowledgement is also given to [PERSON], [PERSON], [PERSON], and [PERSON] for their ongoing support in discussing the themes of this project. Author [PERSON] was employed by the company Bang & Olufsen a/s.