Subjective evaluation of stereoscopic images: effects of camera parameters and display duration

Two experiments are presented that were aimed to investigate the effects of stereoscopic filming parameters and display duration on observers´ judgements of naturalness and quality of stereoscopic images. The paper first presents a literature review of temporal factors in stereoscopic vision, with reference to stereoscopic displays. Several studies have indicated an effect of display duration on performance-oriented (criterion based) measures. The experiments reported were performed to extend the study of display duration from performance to appreciation-oriented measures. In addition, the present study aimed to investigate the effects of manipulating camera separation, convergence distance, and focal length on perceived quality and naturalness, In the first experiment, using display durations of both 5 and 10 s, 12 observers rated the naturalness of depth and the quality of depth for stereoscopic still images. The results showed no significant main effect of the display duration. A small yet significant shift between naturalness and quality was found for both duration conditions. This result replicated earlier findings, indicating that this is a reliable effect, albeit content-dependent. The second experiment was performed using display durations ranging from 1 to 15 s. The results of this experiment showed a small yet significant effect of display duration. Whereas longer display durations do not have a negative impact on the appreciative scores of optimally reproduced stereoscopic images, observers do give lower judgements to monoscopic images and stereoscopic images with unnatural disparity values as display duration increases. In addition, the results of both experiments provide support for the argument that stereoscopic camera toe-in should be avoided if possible