Effects of animation retargeting on perceived action outcomes

The individual shape of the human body, including the geometry of its articulated structure and the distribution of weight over that structure, influences the kinematics of a person's movements. How sensitive is the visual system to inconsistencies between shape and motion introduced by retargeting motion from one person onto the shape of another? We used optical motion capture to record five pairs of male performers with large differences in body weight, while they pushed, lifted, and threw objects. Based on a set of 67 markers, we estimated both the kinematics of the actions as well as the performer's individual body shape. To obtain consistent and inconsistent stimuli, we created animated avatars by combining the shape and motion estimates from either a single performer or from different performers. In a virtual reality environment, observers rated the perceived weight or thrown distance of the objects. They were also asked to explicitly discriminate between consistent and hybrid stimuli. Observers were unable to accomplish the latter, but hybridization of shape and motion influenced their judgements of action outcome in systematic ways. Inconsistencies between shape and motion were assimilated into an altered perception of the action outcome.

[1]  D. W. Joyce,et al.  Kinematic cues in perceptual weight judgement and their origins in box lifting , 2007, Psychological research.

[2]  Jaeho Shim,et al.  Estimation of Lifted Weight and Produced Effort through Perception of Point-Light Display , 2004, Perception.

[3]  Claudia E. Cohen,et al.  Person categories and social perception: Testing some boundaries of the processing effect of prior knowledge. , 1981 .

[4]  Alberto Menache,et al.  Understanding Motion Capture for Computer Animation and Video Games , 1999 .

[5]  S. Runeson,et al.  Kinematic specification of dynamics as an informational basis for person and action perception: Expe , 1983 .

[6]  Michael J. Black,et al.  Coregistration: Simultaneous Alignment and Modeling of Articulated 3D Shape , 2012, ECCV.

[7]  Nikolaus F. Troje,et al.  Perceived naturalness of human motion depends on internal consistency , 2012 .

[8]  Michael J. Black,et al.  MoSh: motion and shape capture from sparse markers , 2014, ACM Trans. Graph..

[9]  S. Runeson,et al.  Visual perception of lifted weight. , 1981, Journal of experimental psychology. Human perception and performance.

[10]  Carol O'Sullivan,et al.  Clone attack! Perception of crowd variety , 2008, ACM Trans. Graph..

[11]  Bernhard Hommel,et al.  Taking the brain serious: introduction to the special issue on integration in and across perception and action , 2007, Psychological research.

[12]  L G Carlton,et al.  Perception of Kinematic Characteristics in the Motion of Lifted Weight. , 1997, Journal of motor behavior.

[13]  Geoffrey P. Bingham,et al.  Seeing Where the Stone Is Thrown by Observing a Point-Light Thrower: Perceiving the Effect of Action Is Enabled by Information, Not Motor Experience , 2014 .

[14]  G. Mather,et al.  Gender discrimination in biological motion displays based on dynamic cues , 1994, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[15]  Nikolaus F. Troje,et al.  Retrieving Information from Human Movement Patterns , 2008 .

[16]  Alberto Menache.  Motion Capture Primer , 2011 .

[17]  James J. Hoffmann,et al.  An Investigation of the Sled Push Exercise: Quantification of Work, Kinematics, and Related Physical Characteristics , 2014 .

[18]  Nikolaus F Troje,et al.  Gaze patterns during perception of direction and gender from biological motion. , 2010, Journal of vision.

[19]  Geoffrey P. Bingham.  Kinematic Form and Scaling: Further Investigations on the Visual Perception of Lifted Weight , 1987 .

[20]  Geoffrey P. Bingham,et al.  Scaling Judgments of Lifted Weight: Lifter Size and the Role of the Standard , 1993 .

[21]  J. Gibson.  The Ecological Approach to Visual Perception , 1979 .

[22]  Hfd Chang,et al.  Shape-Independent Processing of Biological Motion , 2013 .

[23]  Daniel Jokisch,et al.  Biological motion as a cue for the perception of size. , 2003, Journal of vision.

[24]  Alberto Menache.  Understanding Motion Capture for Computer Animation, Second Edition , 2010 .

[25]  Weidong Geng,et al.  Reuse of Motion Capture Data in Animation: A Review , 2003, ICCSA.

[26]  G. Johansson.  Visual perception of biological motion and a model for its analysis , 1973 .

[27]  Boris M. Velichkovsky,et al.  The perception of egocentric distances in virtual environments - A review , 2013, ACM Comput. Surv..

[28]  Michael Gleicher,et al.  Retargetting motion to new characters , 1998, SIGGRAPH.

[29]  Ernst-Joachim Hossner,et al.  Discriminating throwing distances from point-light displays with masked ball flight , 2010 .

[30]  N. Troje,et al.  Person identification from biological motion: Effects of structural and kinematic cues , 2005, Perception & psychophysics.

[31]  Nikolaus F. Troje,et al.  Internal consistency predicts attractiveness in biological motion walkers , 2016 .

[32]  Sebastian Thrun,et al.  SCAPE: shape completion and animation of people , 2005, SIGGRAPH '05.

[33]  Cord Westhoff,et al.  Kinematic cues for person identification from biological motion , 2007, Perception & psychophysics.

[34]  Nikolaus F. Troje,et al.  What is biological motion?: Definition, stimuli and paradigms , 2012 .

[35]  Mark H Johnson,et al.  Biological Motion: A Perceptual Life Detector? , 2006, Current Biology.

[36]  Ludovic Hoyet,et al.  Eye-tracktive: Measuring Attention to Body Parts when Judging Human Motions , 2015, Eurographics.