Perceiving human motion variety

Abstract

Figure 1: The experiment stimuli and their creation -the stimuli as presented to the subject (top) and their creation, with trajectories and characters coloured according to their respective animations (bottom). In the depicted trial, the gold standard is shown on left. Figure 2: Trajectory optimisation -random trajectories result in a large number of intersections (1), causing many collisions (2). Our optimisation approach ensures a collision-free scenario (3, 4). AbstractIn order to simulate plausible groups or crowds of virtual characters, it is important to ensure that the individuals in a crowd do not look, move, behave or sound identical to each other. Such obvious 'cloning' can be disconcerting and reduce the engagement of the viewer with an animated movie, virtual environment or game. In this paper, we focus in particular on the problem of motion cloning, i.e., where the motion from one person is used to animate more than one virtual character model. Using our database of motions captured from 83 actors (45M and 38F), we present an experimental framework for evaluating human motion, which allows both the static (e.g., skeletal structure) and dynamic aspects (e.g., walking style) of an animation to be controlled. This framework enables the creation of crowd scenarios using captured human motions, thereby generating simulations similar to those found in commercial games and movies, while allowing full control over the parameters that affect the perceived variety of the individual motions in a crowd. We use the framework to perform an experiment on the perception of characteristic walking motions in a crowd, and conclude that the minimum number of individual motions needed for a crowd to look varied could be as low as three. While the focus of this paper was on the dynamic aspects of animation, our framework is general enough to be used to explore a much wider range of factors that affect the perception of characteristic human motion.

A Statistical Model for Coupled Human Shape and Motion Synthesis

“…In (Reitsma and 2003), experiments with human observers were conducted to determine the sensitivity of human perception to physical errors in motions and (Hodgins et al, 1998) investigated, which types of anomalies added to the motion disturb human perception the most. In (Pražák and O'Sullivan, 2011) and (McDonnell et al, 2008) human crowd variety was investigated and influence of either motion or shape clones on the whole crowd perception was investigated.…”

Shape up! Perception based body shape variation for data-driven crowds

“…McDonnell et al [1], [5] have studied the effects of different types of appearance and motion variation on the perceptibility of visual clones in crowds, while Pražák et al [2] demonstrated how only three different human motions replicated evenly through a crowd. Hoyet et al [6] evaluated the distinctiveness and attractiveness of different types of human motion and found that average motions were the least distinctive and most attractive, consistent with findings in face perception [7].…”

“…The perception of varied human appearance and motion have previously been studied in this Note: This work was done while all authors were at Disney Research context [1], [2], but to date, body shape variation has received less attention. However, two of the most functionally relevant and visually salient features of any crowd are the shapes and sizes of the people in it, and their relative distributions: i.e., under normal circumstances most people will have shapes close to the median of the population, and there will be decreasing numbers of more atypical bodies present.…”

A Survey of Real‐Time Crowd Rendering

“…Another important aspect to consider when increasing individualism, is the relevance of motion variety. In [PO11] perception studies were carried out to determine how people detect motion clones. Table 1 summarizes the crowd rendering approaches discussed in previous sections, considering the underlying representation and an-imation technique.…”

“…Both approaches thus benefit from matrix compression techniques. It is also possible to reduce the frequency at which animations are updated with no visible artefacts [PO11, MNO07].…”