Chapter 4: Spontaneous
Morphing
Heather Oh - Ryan Cho - Jennifer Tam
Dorsal Simultanagnosia
What exactly is a part?
-
Transversal Intersection:
-at points where the two objects join
together(intersect)
Concave creases- sharp edges in the surface
that point into the object
Convex creases- sharp edges in the surface
that point out of the object
Rule #14. Rule of concave creases: Divide
shapes into parts along concave creases.
-Any object may be an example.
-Where things seem to join together.
-Where surface degree changes.
Schroder Staircase
-Surface Normals:
-Positive
-Negative
-Zero
MOBIUS STRIP
Main Points:
-Surface normals and its connection to concave and
convex creases. Where do they point?
-Bubble out of water vs. Bubble inside of water
-What do we really pay attention to?
-Example: the mushrooms
Principal Curvatures: Positive, Negative, or zero.
Figure & Ground
If the normals point outward, then the principal curvature is positive.
If the normals point inward, then the principal curvature is negative.
When the crease has been smoothed, the crease turns into a point of
high curvature.
Subjective and Selective Attention
-Rule #15. Minima Rule: Divide shapes into parts at negative
minima, along lines of curvature, of the principle curvatures.
-Examples:
•Fusilli Pasta
•Keys
•The ‘Ripple’
Ripple
Silhouettes
Rule #16. Minima rule for silhouettes: Divide silhouettes into parts
at concave cusps and negative minima of curvature.
•Examples:
Face & Goblet
Similarity
Symmetry vs. Repetition
-Point 1: Repetition should be easier to recognize because
it is the exact same thing (object or image), just repeated. (the
corresponding parts are always equally spaced apart)
-Point 2: According to the minima rule, symmetry is easier
to see because the curves repeat at the same point and the
curvatures of the first object match the second figure.
Rabbit-Duck
The minima rule predicts that you should more easily recognize
the objects on the right than on the left because…
Questions we ask ourselves
-What do we notice more?
-What should we divide?
Example: Cooking
Rule #17: The Salience of a cusp boundary increases with
increasing sharpness of the angle at the cusp.
Rule #18: The salience of a smooth boundary increases with the
magnitude of normalized curvatures at the boundary.
Rule #19. Salient boundaries: Choose figure and ground
so that figure has the more salient part boundaries.
Rule 20: Salient Parts
Choose figure and ground so that figure has the more salient parts.
The recognizable difference between the figure and ground
of objects is crucial for every day survival and decision making.
Without understanding simple tasks such as picking up the
butcher knife by the handle as opposed to the blade, would result
in unpleasant consequences.
Bibliography
Hoffman, Dr. Donald D. Visual Intelligence: How we create what we see. 1998. W.W.
Norton and Company, Inc. United States of America.
Jongen, Hubertus Th., Jonker, Peter, Twilt, Frank. Nonlinear Optimization in Finite
Dimensions: Morse Theory, Chebyshev Approximation, Transversality, Flows,
Parametric Aspects. 2000. Kluwer Academic Publishers. Netherlands.
Also, we used images downloaded from www.google.com and www.yahoo.com