> Motivation
> Example Movie
> Comment
> Conclusion
> Related Experiments
> Setup


Performance Photo

Screenshot

 

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Motivation

If the dancer reproduces a movement in slow motion, we either consider it to be an original movement, or - if we know the original model - we recognize it as the slow motion version of an original. If we know that a movement is intended to be a slow motion without knowing the original, are we able to construct the movement in our minds? How does the imagination differ from a technical reconstruction of the original movement simply achieved by speeding up a video recording? The influence of physics on the body motion in different speeds should be noticeable. We let the dancer move in slow motion and accelerate the overlaid video-playback.

 

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Example Movie

Stage View
Computer Image
Similar to : as the dancer slowly progresses through a movement sequence, short parts of this sequence are played back. Those played back parts show the movement of a few seconds before. As the recorded parts are played back faster than the original tempo they catch up to the current movement and moment in time.

 

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Comment

In the first half of this trial Thomas decided to execute a dance phrase slower than it was choreographed, so that his historical double would be dancing the choreography in its original tempo. The second half is Thomas' exploration (with the sensor) of this moving video body. He examines details like just the legs or torso, how the head moves in counterpoint to the arms. Understanding the kind of slow timing of movements this experiment is demanding Thomas reaches a level of playing and chasing himself.

Then at one moment there appears a third body. A 'bookmarker' holds Thomas' place while he continues the examination that brings him closer and closer to the moving body and the dance that is advancing. During the last minute of the video excerpt, the slowness of Thomas' dance is at times hypnotizing. Then a jump into the replayed material makes one focus again. Soon Thomas finds himself pulled back into the phrase itself only to make a finish of it and wait for his video double to catch up to him.

 

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Conclusion

We did not expect that the accelerated image - even with a speed up factor of four like in the beginning of the sequence - would still result in a believable motion. Of course it is essential, that the dancer's motion is motivated only by internal forces of the body and that it is not superimposed by external factors like gravity or body inertia. But with slow motions the body anyway has to be in balance. It is not surprising that an accelerated motion-playback, which exceeds a reasonable speed looks like one of the pioneer movie recordings.

In terms of perception we guess it would be hard for an untrained spectator to construct the accelerated motion - given the length in the experiment - out of his memory. The overlaid fast replay provides sufficient hints to be able to mentally link the faster motion to his current motion - even if one does not slavishly watch the projection screen.

 

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Related Experiments:

 

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Setup

 


Hardware:

  • Graphics PC with Video Capture Card
  • Projector
  • Polhemus tracking system: 1 Sensor
  • Video Camera



Configuration:

  • The Video Camera is facing the dancer and transmits a live video image to the graphics computer. The graphics computer displays this image on the projection screen. The image is overlaid by a round spot, which shows a time lapsed video playback of the last 15 seconds in 5 second intervals. The computer continuously stores the incoming video frames in a frame queue. A looped internal timer selects one out of these stored images and displays it within the spot.
  • The Sensor controls the position of the spot on screen. In the recording we attached the sensor to the dancer's left hand.

 


Technical Setup

Spatial Setup

Technical Screenshot

Screenshot
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