Recognizing 3d figures

• I got mostly right, with top middle as also 3d, not top left.
• There is something going on with multi hederal shapes (shapes having points, where multiple surfaces meet)
• Of course there is ambiguity as for few figures, different people perceive differently

Gibberish Sentences

Why do we think some are grammatically correct and some are not. There are some hidden constraints.

Constraint Propogation Defined

• 3D figure: Note that one could view it as popping out structure (an open box) or popping in (a building top view). both could be valid satisfying all constraints
• The same applies for sentences. In Understanding we used constraints in propositions, assigning allowable values for certain propositions in the example.

From Pixels to 3D

According to Mars theory, the human visual system first understands edges/lines, then surfaces and then as 3D

Constraints Intersections and Edges

In world of tri hedral objects, we could identify above junctions (and they are not only ones)

• A fold is a line where 2 surfaces meet.
• In a Y junction, each line is a fold
• Important property of Y: If one is a fold, then through same reasoning other lines also should be fold
• A blade is a line wherew e cannot infer 2 surfaces are getting connected.
• There could be more formulation for L, but we are keeping simple here.

• In speech, we follow similar constraints.

Quiz

• Note for Y, all 3 angles are within 180 degrees
• For W, one of the 3 angles should be more than 180 degrees
• For T, one of angles is exactly 180 degrees

• Note, the lines named as folds, stand out to make the object look like 3D

Why ambiguity? Complex Ontology

• creates a fold-blade conflict, has 4 lines meeting at a junction as David said.
• answer is, this has a complex ontology, so ambiguity arises.

NLP