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Recognition of tennis serve performed by a digital player: comparison among polygon, shadow, and stick-figure models.

Ida H, Fukuhara K, Ishii M - PLoS ONE (2012)

Bottom Line: As far as the experienced players were concerned, the polygon model decreased the discrimination accuracy as compared with the stick-figure model.This result suggests that the simplified visual information can bias the perception of the motion speed toward slower.It was also shown that the increasing the joint rotation speed increased the perceived swing speed, although the resulting racket velocity had little correlation with this speed sensation.

View Article: PubMed Central - PubMed

Affiliation: Department of Human System Science, Tokyo Institute of Technology, Tokyo, Japan. hiroida@me.com

ABSTRACT
The objective of this study was to assess the cognitive effect of human character models on the observer's ability to extract relevant information from computer graphics animation of tennis serve motions. Three digital human models (polygon, shadow, and stick-figure) were used to display the computationally simulated serve motions, which were perturbed at the racket-arm by modulating the speed (slower or faster) of one of the joint rotations (wrist, elbow, or shoulder). Twenty-one experienced tennis players and 21 novices made discrimination responses about the modulated joint and also specified the perceived swing speeds on a visual analogue scale. The result showed that the discrimination accuracies of the experienced players were both above and below chance level depending on the modulated joint whereas those of the novices mostly remained at chance or guessing levels. As far as the experienced players were concerned, the polygon model decreased the discrimination accuracy as compared with the stick-figure model. This suggests that the complicated pictorial information may have a distracting effect on the recognition of the observed action. On the other hand, the perceived swing speed of the perturbed motion relative to the control was lower for the stick-figure model than for the polygon model regardless of the skill level. This result suggests that the simplified visual information can bias the perception of the motion speed toward slower. It was also shown that the increasing the joint rotation speed increased the perceived swing speed, although the resulting racket velocity had little correlation with this speed sensation. Collectively, observer's recognition of the motion pattern and perception of the motion speed can be affected by the pictorial information of the human model as well as by the perturbation processing applied to the observed motion.

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Discrimination accuracy of modulated joint.Percentage of correct responses (M ± SD) for the experienced group (A) and novice group (B). *: p<.05 in planned two-way ANOVA, †: above chance level (33.3%), and ‡: below chance level.
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pone-0033879-g001: Discrimination accuracy of modulated joint.Percentage of correct responses (M ± SD) for the experienced group (A) and novice group (B). *: p<.05 in planned two-way ANOVA, †: above chance level (33.3%), and ‡: below chance level.

Mentions: The discrimination responses for the three-alternative choice of the modulated joint (wrist, elbow or shoulder) were examined to determine the total accuracy, as well as the individual accuracy for each joint (Figure 1). The discrimination accuracies of the experienced group were significantly above chance level (33.3%) for the wrist modulation in the stick-figure model; for the elbow modulation in all display models; and for the total score in the stick-figure model. On the other hand, the discrimination accuracies for the shoulder modulations in all display models were significantly below chance level in the experienced group. In the novice group, no responses were above chance level, and in the case of the shoulder modulation within the polygon model significantly below chance level.


Recognition of tennis serve performed by a digital player: comparison among polygon, shadow, and stick-figure models.

Ida H, Fukuhara K, Ishii M - PLoS ONE (2012)

Discrimination accuracy of modulated joint.Percentage of correct responses (M ± SD) for the experienced group (A) and novice group (B). *: p<.05 in planned two-way ANOVA, †: above chance level (33.3%), and ‡: below chance level.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3306305&req=5

pone-0033879-g001: Discrimination accuracy of modulated joint.Percentage of correct responses (M ± SD) for the experienced group (A) and novice group (B). *: p<.05 in planned two-way ANOVA, †: above chance level (33.3%), and ‡: below chance level.
Mentions: The discrimination responses for the three-alternative choice of the modulated joint (wrist, elbow or shoulder) were examined to determine the total accuracy, as well as the individual accuracy for each joint (Figure 1). The discrimination accuracies of the experienced group were significantly above chance level (33.3%) for the wrist modulation in the stick-figure model; for the elbow modulation in all display models; and for the total score in the stick-figure model. On the other hand, the discrimination accuracies for the shoulder modulations in all display models were significantly below chance level in the experienced group. In the novice group, no responses were above chance level, and in the case of the shoulder modulation within the polygon model significantly below chance level.

Bottom Line: As far as the experienced players were concerned, the polygon model decreased the discrimination accuracy as compared with the stick-figure model.This result suggests that the simplified visual information can bias the perception of the motion speed toward slower.It was also shown that the increasing the joint rotation speed increased the perceived swing speed, although the resulting racket velocity had little correlation with this speed sensation.

View Article: PubMed Central - PubMed

Affiliation: Department of Human System Science, Tokyo Institute of Technology, Tokyo, Japan. hiroida@me.com

ABSTRACT
The objective of this study was to assess the cognitive effect of human character models on the observer's ability to extract relevant information from computer graphics animation of tennis serve motions. Three digital human models (polygon, shadow, and stick-figure) were used to display the computationally simulated serve motions, which were perturbed at the racket-arm by modulating the speed (slower or faster) of one of the joint rotations (wrist, elbow, or shoulder). Twenty-one experienced tennis players and 21 novices made discrimination responses about the modulated joint and also specified the perceived swing speeds on a visual analogue scale. The result showed that the discrimination accuracies of the experienced players were both above and below chance level depending on the modulated joint whereas those of the novices mostly remained at chance or guessing levels. As far as the experienced players were concerned, the polygon model decreased the discrimination accuracy as compared with the stick-figure model. This suggests that the complicated pictorial information may have a distracting effect on the recognition of the observed action. On the other hand, the perceived swing speed of the perturbed motion relative to the control was lower for the stick-figure model than for the polygon model regardless of the skill level. This result suggests that the simplified visual information can bias the perception of the motion speed toward slower. It was also shown that the increasing the joint rotation speed increased the perceived swing speed, although the resulting racket velocity had little correlation with this speed sensation. Collectively, observer's recognition of the motion pattern and perception of the motion speed can be affected by the pictorial information of the human model as well as by the perturbation processing applied to the observed motion.

Show MeSH
Related in: MedlinePlus