Note Geon Theory, Visual Perception, Bruce Green Georgeson, 1996, p 222

Object recognition is based on fundamental shapes, geons, which are assembled as the building blocks of an object. Segmentation is along the lines of Hoffman and Richards (1986) - concavitites in segmenting contours reveal parts for recognition. (p220)

"...Pentland (1986a) proposed a more flexible system of volumetric representation than can be achieved with generalised cones. Pentland suggests that most complex natural shapes are comprised of superquadric components and that these might be the basic components that we recover when analysing images of natural objects. Superquadrics include simple shapes such as spheres and wedges, and all kinds of deformations on these shapes that preserve their smoothly varying form and that do not introduce concavities."

"... In Biederman's theory, complex objects are described as spatial arrangements of basic component parts. These parts come from a restricted set of basic shapes such as wedges and cylinders. Biederman calls these shape primitives "geons"... Like Marr and Nishihara, Biederman suggests that the fist stage of object description involves the segmentation of the occluding contour at regions of sharp concavity. this divides the contour into a number of parts, which can then be matches against representations of the primitive object shapes (geons)... The main point of departure of Biederman's theory from Marr and Nishihara's is the suggestion that geons are defined by properties which are invariant over different views... each different kind of geon has its own "key" features in the 2D primal sketch level representation."

"Non accidental properties include collinearity, curviliniarity, symmetry, parallelism, and co-termination..."

Hoffman DD and Richards WA: Parts of Recognition, Cognition, 18, 65-96

Pentland A, Local Shading Analysis. In AP Pentland Ed. From Pixels to Predicates, Norwood New Jersey: Ablex.

Biederman I,

1987a: Recognition by components: 'A Theory of human image understanding' Psychological Review 94, 115-147

1995: etc - see Visual Perception list.

Proposition in the Sentic Hypothesis:

Geons are the same as sentic forms. They aid not only recognition of the object, but how to relate emotionally to it and its parts. The bits with teeth, claws, stings, thorns. The bits which might break. The bits which ask to be fondled. The bits which ask to be sucked. Etc.