week 1: what does it mean to see?
-
plan for the semester:
- what does it mean to see [structure]?
- take 1: symbolic structural descriptions
- interlude: psychophysical and neurobiological findings
- take 2: multidimensional feature spaces
- what it means to see (I think)
-
plan for this week:
- to see is... to perform object recognition
-
beyond recognition: several structure-related tasks [can
you think of any others?]
-
the nature of features
-
main challenges:
- independence
- productivity
- systematicity
- a solution: compositionality
- a price: binding problems
to see is...
...
to know what is where by looking
[David Marr, Vision, 1982, p.3]
in other words, to see is... to do object
recognition!
slide 3
so...
so you think you can tell...
... heaven from hell, blue sky from pain, ...
... where one object ends and another begins?
slide 4
so...
so you think you can tell...
... heaven from hell, blue sky from pain, ...
... where one object ends and another begins?
low-level vision should not be taken for granted
but we shall do it nevertheless, provisionally
slide 5
so...
so you think you can tell...
... heaven from hell, blue sky from pain, ...
... where one object ends and another begins?
low-level vision should not be taken for granted,
but we shall do it nevertheless, provisionally
so, to see is...
...
to know what is where by looking
[David Marr, Vision, 1982, p.3]
in other words, to see is... to do object recognition!
slide 6
is that all?
is object recognition all there is to seeing?
no, it is not; we need to address the issues surrounding
object/scene structure
slide 7
a structure-related task
Given two objects, or an object and a class prototype,
identify their corresponding regions.
The correspondence here may be based on
-
local shape similarity (find the eyes of a face in a Cubist painting),
or
-
similar role played by the regions in the global
structure (find the eyes in a smilie icon).
slide 8
a structure-related task
Given an object and an action, identify a region in the object towards
which the action can be directed.
Similarities between objects vis à vis this task are defined
functionally (as in the parallel that can be drawn between
the handle of a pan and a door handle: both afford grasping).
slide 9
a structure-related task
Given an object, describe its structure.
This explicitly structural task arises in the context of trying to make
sense of an unfamiliar object (as in perceiving a hot-air balloon, upon
seeing it for the first time, as a pear-like shape over a box-like one).
slide 10
challenge: independence
slide 12
challenge: independence
slide 13
challenge: productivity
slide 14
challenge: systematicity
"A cognitive agent, C, exhibits systematicity just in case its cognitive
architecture causally ensures that C has the capacity to be in a
propositional attitude (A) towards proposition aRb if and only if C
has the capacity to be in attitude (A) towards proposition bRa."
R. F. Hadley, 1997; G. Evans, 1982
 |
| aRb | bRa |
slide 15
solution: compositionality
Gottlob
Frege:
the meaning of the whole is a function of the meaning of the
parts
slide 16
(compositional) structural descriptions
slide 17
price: binding problems
- Property binding
- Part binding
- Range binding
- Hierarchical binding
- Conditional binding
- Temporal binding
- Location binding, in which objects are bound
to their current locations. Objects and locations
appear to be separately coded in ventral and dorsal
pathways, respectively, raising what may be the most
basic binding problem: linking `what' to `where.'
slide 18
a person
slide 19
a zoo
slide 20
is it safe?
slide 21
is it safe? will it scale?
slide 22
supplementary material
