Impact of Crowd Density and Camera Perspective on User Sensitivity Towards Impostor Resolution Degradation in Crowd Simulators

Sammanfattning: The entertainment industry and research departments feature many applications of crowd simulation. Typically, it does not suffice to simply generate crowds large in number; they must also be realistic in terms of behaviour and visual fidelity, which is far from an easy or computationally cheap task. Because of this, methods to simulate crowds in a realistic manner while keeping complexity at a manageable level must be explored and implemented. Implementing impostors in crowd simulation is a ubiquitous technique for managing rendering complexity. Impostors, 2D image representations of virtual 3D objects, improve performance due to their relative simplicity, and can be implemented with varying resolution depending on performance needs; the lower the image resolution of impostors, the higher the efficiency. Not all crowds are the same, some are denser, while others are sparse. On the same note, the scenarios, and thus viewing perspectives, in which crowds are found vary as well; some crowds are seen at eye-level, others from a bird’s-eye view. This thesis explores how viewers’ sensitivity towards impostor resolution degradation is affected by crowd density and perspective. This is done by conducting a user study in which participants are shown a number video clip pairs. Each pair features clips showing the same crowd scenario, but with one clip only containing high-resolution impostors, and one clip with a gradually increasing share of low-resolution impostors. For each video clip pair, participants are tasked with identifying the one clip containing low-resolution impostors as quickly as possible. The video clip pairs feature different combinations of crowd density and viewing perspective, and the results from the study show that crowd density has a significant effect on viewers sensitivity towards impostor resolution degradation. Although perspective seems to have an indicative effect, it was not found to be significant.