Comparing Sky Shape Skeletons for the Analysis of Visual Dynamics along Routes

The motion of an observer in a given space produces a particular perception called motion perspective. This has been defined by Gibson as the gradual changes in the rate of displacements of contour lines in the visual field of the observer. This paper describes a new approach intended for analysing the motion perspective in order to quantify the morphology of urban open spaces along routes. It is based on spherical projections, which provide the shape of the sky boundary around the observer. The projections are studied through their skeletons, which are continuous sets of curves obtained by a progressive thinning down of the shapes around their main saliencies. The proposed method uses these skeletons to follow the variations in the shape of the sky boundary between the successive views. Measures of these variations have been developed and applied in a range of simplified theoretical examples and a real field example in order to show that they succeeded in capturing significant variations in spherical projections.

[1]  Benjamin B. Kimia,et al.  Perceptual organization via the symmetry map and symmetry transforms , 1999, Proceedings. 1999 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (Cat. No PR00149).

[2]  Philip N. Klein,et al.  A tree-edit-distance algorithm for comparing simple, closed shapes , 2000, SODA '00.

[3]  Anil K. Jain,et al.  A modified Hausdorff distance for object matching , 1994, Proceedings of 12th International Conference on Pattern Recognition.

[4]  Mahbub Rashid,et al.  On the Description of Shape and Spatial Configuration inside Buildings: Convex Partitions and Their Local Properties , 1997 .

[5]  Michel Couprie,et al.  Discrete Bisector Function and Euclidean Skeleton , 2005, DGCI.

[6]  Michael Batty,et al.  Encoding Geometric Information in Road Networks Extracted from Binary Images , 2005 .

[7]  Hans-Peter Seidel,et al.  Hyperbolic Hausdorff Distance for Medial Axis Transform , 2001, Graph. Model..

[8]  Carlo Ratti,et al.  Raster Analysis of Urban Form , 2004 .

[9]  Peter Bosselmann,et al.  Representation of Places: Reality and Realism in City Design , 1998 .

[10]  Philip Thiel,et al.  A Sequence-Experience Notation , 1961 .

[11]  M. Benedikt,et al.  To Take Hold of Space: Isovists and Isovist Fields , 1979 .

[12]  Jacques Teller,et al.  Visual Urban Space Assessment from Sky Shape Analysis , 2003, EnviroInfo.

[13]  Alasdair Turner,et al.  Analysing the Visual Dynamics of Spatial Morphology , 2003 .

[14]  Michel Pocchiola,et al.  The visibility complex , 1993, SCG '93.

[15]  Günter Rote,et al.  Computing the Minimum Hausdorff Distance Between Two Point Sets on a Line Under Translation , 1991, Inf. Process. Lett..

[16]  Jacques Teller,et al.  A Spherical Metric for the Field-Oriented Analysis of Complex Urban Open Spaces , 2003 .

[17]  William Rucklidge,et al.  Efficient Visual Recognition Using the Hausdorff Distance , 1996, Lecture Notes in Computer Science.

[18]  J. Koenderink,et al.  The singularities of the visual mapping , 1976, Biological Cybernetics.

[19]  Frédo Durand,et al.  The visibility skeleton: a powerful and efficient multi-purpose global visibility tool , 1997, SIGGRAPH.

[20]  Michael Batty,et al.  Exploring Isovist Fields: Space and Shape in Architectural and Urban Morphology , 2001 .

[21]  R. Hetherington The Perception of the Visual World , 1952 .

[22]  Michael Burt,et al.  A 3-D Visual Method for Comparative Evaluation of Dense Built-up Environments , 2003 .

[23]  Jacques Teller,et al.  Townscope II—A computer system to support solar access decision-making , 2001 .

[24]  Kaleem Siddiqi,et al.  Hamilton-Jacobi Skeletons , 2002, International Journal of Computer Vision.

[25]  A. Turner,et al.  From Isovists to Visibility Graphs: A Methodology for the Analysis of Architectural Space , 2001 .

[26]  Dafna Fisher-Gewirtzman,et al.  View-oriented three-dimensional visual analysis models for the urban environment , 2005 .

[27]  Frédo Durand,et al.  The 3D Visibility Complex: A New Approach to the Problems of Accurate Visibility , 1996, Rendering Techniques.