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Qualitative sketch optimization

Published online by Cambridge University Press:  27 February 2009

Amitabha Mukerjee
Affiliation:
Department of Mechanical Engineering, Indian Institute of Technology, Kanpur, Kanpur 208016, India
Ram Bhushan Agrawal
Affiliation:
Department of Mechanical Engineering, Indian Institute of Technology, Kanpur, Kanpur 208016, India
Nivedan Tiwari
Affiliation:
Department of Mechanical Engineering, Indian Institute of Technology, Kanpur, Kanpur 208016, India
Nusrat Hasan
Affiliation:
Department of Mechanical Engineering, Indian Institute of Technology, Kanpur, Kanpur 208016, India

Abstract

The “sketch” drawn by a human designer represents a shape class of wider variability than can be captured by traditional CAD models; these typically work with parametrizations based on a nearly finished shape. Traditional Qualitative Reasoning is also unable to model this degree of ambiguity in shape. Cognitively, shapes are often represented in terms of an axial model. In defining 2D contours, such an axial representation is called the Medial Axis Transform or MAT. By perturbing the parameters of the MAT—length, link angle, and the node radius—one can define a shape class. Unlike the contour-to-MAT transform, which is well-known to be unstable, the MAT-to-contour process is an integrative process and is very stable. The variation in these parameters can be controlled by defining a suitable discretization over the parameter space. This leads to a broad class of similar shapes from which an optimized shape can be obtained for a given set of criteria. The optimizing criteria may involve the boundary description for each shape; the axial model is only used for generating the shape class. This Qualitative MAT model has been tested in several design optimization contexts, using Genetic Algorithms, and we show results for Automobile contours, IC engine parts, building profiles, etc.

Type
Articles
Copyright
Copyright © Cambridge University Press 1997

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References

REFERENCES

Biederman, I. (1990). Higher level vision. In Chapter Vision 2, Visual Cognition and Action (Osherson, D.N., et al. , Ed.) pp. 4172. MIT Press, Cambridge, MA.Google Scholar
Cohn, A. (1995). A hierarchical representation of qualitative shape based on connection and convexity. International Conference on Spatial Information Theory COSIT-95.CrossRefGoogle Scholar
Damski, J., & Gero, J. (1994). Artif. Intell. Design Workshop Notes (AID-94), 1620.Google Scholar
Dickinson, S.J., Pentland, A.P., & Rosenfeld, A. (1992). Qualitative 3-D shape reconstruction for 3-D object recognition. IEEE Transactions on Pattern Analysis and Machine Intelligence.Google Scholar
Forbus, K.D., Nielsen, P., & Faltings, B. (1991). Qualitative spatial reasoning: The CLOCK project. Artif. Intell. 51, 417471.CrossRefGoogle Scholar
Fortune, S. (1987). A sweepline algorithm for voronoi diagrams. Algorithmica, 2, 153174.CrossRefGoogle Scholar
Goldberg, D.E. (1989). Genetic algorithms in search, optimization, and machine learning. Addison-Wesley, Reading, MA.Google Scholar
Hernandez, D., Clementini, E., & Di Felice, P. (1995). Qualitative distances. Int. Conf. Spatial Infor. Theory.CrossRefGoogle Scholar
Kautz, H.A., & Ladkin, P.B. (1991). Integrating metric and qualitative temporal reasoning. AAAI-91.Google Scholar
King, J.S. (1991). Inexact visualization: Qualitative shape representation for recognizable reconstruction. Master's Thesis. Department of Computer Science, Texas A and M University.Google Scholar
King, J.S., & Mukerjee, A. (1990). Inexact visualization. Proc. IEEE Conf. Biomed. Visualization, 136143.CrossRefGoogle Scholar
Kuipers, B. (1994). Qualitative reasoning, modeling and simulation with incomplete knowledge. MIT Press, Artificial Intelligence Series, Reading, MA.Google Scholar
Mukerjee, A., Agarwal, M., & Bhatia, P. (1995). A qualitative discretization for 3D contact motions. IJCAI-95, 915921.Google Scholar
Mukerjee, A. (1990). Qualitative geometric design. In Solid Modeling Foundations and CAD/CAM Applications (Rossignac, J.R. and Turner, J., Eds.), Springer Verlag, New York.Google Scholar
Mukerjee, A. (1997). Neat vs Scruffy: A review of computational models for spatial expressions. In Representation and Processing of Spatial Expressions (Olivier, P. and Gapp, K-P., Eds.), Lawrence Erlbaum Associates, Mahwah, NJ.Google Scholar
Requicha, A.A.G. (1980). Representation for rigid solids: Theory, methods, and systems. ACM Computer Surveys.CrossRefGoogle Scholar
Schlieder, C. (1994). Qualitative shape representation. In Spatial Conceptual Models for Geographic Objects with Undetermined Boundaries, (Frank, A., Ed.), Taylor & Francis, London.Google Scholar
Sun, K., & Faltings, B. (1994). Supporting creative mechanical design. In Artificial Intelligence in Design (Gero, J.S. and Sudweeks, F., Eds.), pp. 3956. Kluwer, New York.Google Scholar
Wainwright, S. (1988). Axis and circumference, the cylindrical shape of plants and animals. Harvard University Press, Cambridge, MA.CrossRefGoogle Scholar