Action Synopsis: Pose Selection and Illustration

Jackie Assa Yaron Caspi Daniel Cohen-Or

School of Computer Science - Tel Aviv University

(a)	(b)	(c)

Action synopsis analyzes the motion-curve embedded in a low dimensional space (a); super-positioning of carefully selected poses (b) vs. uniform sampling (c)

Abstract:

Illustrating motion in still imagery for the purpose of summary, abstraction and motion description is important for a diverse spectrum of fields, ranging from arts to sciences. In this paper, we introduce a method that produces an action synopsis for presenting motion in still images. The method carefully selects key poses based on an analysis of a skeletal animation sequence, to facilitate expressing complex motions in a single image or a small number of concise views. Our approach is to embed the high-dimensional motion curve in a low-dimensional Euclidean space, where the main characteristics of the skeletal action are kept. The lower complexity of the embedded motion curve allows a simple iterative method which analyzes the curve and locates significant points, associated with the key poses of the original motion. We present methods for illustrating the selected poses in an image as a means to convey the action. We applied our methods to a variety of motions of human actions given either as 3D animation sequences or as video clips, and generated images that depict their synopsis.

Overview of the method:

The input animation sequence (a) is analyzed. Aspects of a single joint (character's elbow) are displayed in (b) as a function of time. Affinity matrices (dissimilarities between poses) of the aspects are computed using all joint data (c). Key-poses (d) are extracted by embedding the motion curve in a low dimensional Euclidean space. Key poses are local extremum points of the motion curve (e). Synopsis views (f) display a superposition of key-poses.

Technical report: (conference version appears in SIGGRAPH 2005 proceedings) (note that this is only a draft at this stage…)
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More examples and work:
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BibTeX entry:
@inproceedings{assa2005,
 author = {Jackie Assa and Yaron Caspi and Daniel Cohen-Or},
 title = {Action Synopsis: Pose Selection and Illustration},
 year = {2005},
 pages = {},
 location = {Los Angeles, California, USA},
 publisher = {ACM Press}
}

SIGGRAPH 2005 presentation:
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An example for an application: motion capture library thumbnails.

Key poses user survey application

Select to download the application. The application requires Microsoft .Net framework (1.1 or above)