Transcript B i g I m a g e s - Kees van Overveld

From Light to
Enlightenment
Edition Honours Class ‘Big Images’ TU/e 2014
Kees van Overveld
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From Light to Enlightenment
Introduction: what is looking?
Exercise1.
• Describe in at most one sentence (<20
words) the essence of what you will see
next.
‘I see …’
Kees van Overveld
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Kees van Overveld
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Kees van Overveld
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From Light to Enlightenment
Introduction: what is ‘looking’?
Anwers:
1.
2.
3.
4.
5.
6.
7.
8.
I see the light of the beamer being reflected from the screen
I see a distribution of light shades in the middle, brownish near the
borders
I see mainly smooth color distributions, granular in the middle and
patches near the borders
I see few light, rounded, symmetric 2D shapes in the middle and a
rounded triangle in the lower left
I see a roughly spherical shape in the middle and few flat, laying 3D
shapes underneath
I see a cup of cappuccino and a newspaper
I see the cup being almost full and the newspaper not (yet) opened
I see the careless beginning of a promising holiday in Italy
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From Light to Enlightenment
Introduction: what is ‘looking’??
Answers:
1.
2.
3.
4.
5.
6.
7.
8.
I see the light of the beamer being reflected from the screen
I see a distribution of shades of grey
I see mainly smooth distributions of grey, granular in places
I see few dark lines, few swirls, blotches and scratches
I see a – presumably – flat surface with some black shapes in it
I see some traces of elementary particles in a bubble chamber
I see a reaction between sub-atomic particles with various charges
and masses, with lacking momentum
I see the first ever empirical evidence of a neutrino
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From Light to Enlightenment
Introduction: what is an ‘image’?
Exercise 2.
• For the images of exercise 1, explain
where they reside.
• Hint: there are at least 10 different
correct answers.
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From Light to Enlightenment
Introduction: what is an ‘image’?
Answers:
•
•
•
•
•
•
•
•
•
•
In the museum and in the bubble chamber at the instance of the
nuclear reaction, respectively
In former downtown lunchroom Peacock (‘Heuvelgalerie’), where I took
the photograph, and the Wikipedia archive, respectively
At the hard disk of my computer
In the beamer
In the space between the beamer and the screen, or between the
screen and your eyes
In your eye
In your retina
In your brain
In your mind
In the sound waves in this room while we are talking about them
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From Light to Enlightenment
Introduction: what is an ‘image’?
We are certain that an image may reside in our head (‘I dream
therefore I see’: immediate access to our internal virtual subjective omnimax theatre)
All other answers
apply only under
certain
circumstances
So: the only thing
that holds with
certainty for each
image, is that it has
a mental, and
therefore subjective
representation.
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From Light to Enlightenment
Introduction: what is an ‘image’?
Two problems:
1.
We don’t know how something looks
in reality
Mutually parallel or
perpendicular lines or
curves?
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From Light to Enlightenment
Introduction: what is an ‘image’?
Two problems:
2. We don’t know what is to be seen in someone else’s private theatre
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From Light to Enlightenment
Introduction: what is an ‘image’?
How could we ever intersubjectively know something
about images???
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From Light to Enlightenment
Introduction: what is an ‘image’?
Answer:
Thanks to the miracle of equivalence and the
tendency of clustering, innate in our brains.
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From Light to Enlightenment
Introduction: what is an ‘image’?
Answer:
Thanks to the miracle of equivalence and the
tendency of clustering, innate in our brains.
These are more
similar …
.. .than these
‘being similar’ ’color’
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From Light to Enlightenment
Introduction: what is an ‘image’?
Answer:
Thanks to the miracle of equivalence and the
tendency of clustering, innate in our brains.
These are more
similar …
… than these
‘being similar’ ’shape’
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From Light to Enlightenment
Introduction: what is an ‘image’?
Answer:
Thanks to the miracle of equivalence and the
tendency of clustering, innate in our brains.
These are
more similar
…
… than these
‘being similar’ size’
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From Light to Enlightenment
Introduction: what is an ‘image’?
Preliminar conclusion:
A visible property
(‘color’, ‘shape’, ‘size’, …)
is the same thing as
‘a way of clustering’
or
an equivalence relation
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From Light to Enlightenment
Introduction: what is an ‘image’?
Q: what is an equivalence relation?
A: a statement about relating two elements in a
set, e.g. : ‘equally heavy’, ‘having the same
father’, ‘is connected to’, …
… where this relation is
Reflective
M(a,a)
Symmetric
M(a,b)  M(b,a)
Transitive
M(a,b) & M(b,c)  M(a,c)
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From Light to Enlightenment
Introduction: what is an ‘image’?
Example (‘same amount’):
~
~
~…
The class of all sets containing three elements,
simply called ‘THREE’
~
~
~…
The class of all sets containing four elements,
simply called ‘FOUR’
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From Light to Enlightenment
Introduction: what is an ‘image’?
So:
Equivalence relations bring forward classes of
elements, where all elements in a class are
mutually equivalent, so called Equivalence
classes.
Equivalence classes are disjoint and covering.
An equivalence class is a convenient way to
define something abstract, such as THREE or
FOUR, being equivalence classes of ‘equally
many’.
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From Light to Enlightenment
Introduction: what is an ‘image’?
Apply to images:
•‘Looks similar to’ is (almost) an equivalence relation.
•‘Looks similar w.r.t. color’ has equivalence classes RED,
GREEN, … etc
•‘Looks similar w.r.t. shape’ has equivalence classes
ROUND, SQUARE, … etc
•‘Looks similar w.r.t. size’ has equivalence classes
LARGE, SMALL, … etc
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From Light to Enlightenment
This is an Inevitable shortcoming of our
brain (and every measuring instrument),
but at the same time an evolutionary
advantage, provided that cluster
boundaries have evolutionary meaningful
interpretations
Introduction: what is an ‘image’?
Apply to images:
•‘Is similar to’ is (almost) an equivalence relation ….
… but not quite: transitivity only holds in approximation.
… does not look
similar to
..similar to.. Similar to
Similar to Similar to
The terminology to argue
about properties of images
Kees van Overveld
… this is also true for
textures, shapes, 3D
surfaces, objects and
relalions and meaning
VARIANTS: the variety
within one equivalence
class
INVARIANTS: that what
distinguishes one
equivalence class from
another
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From Light to Enlightenment
Introduction: what is an ‘image’?
Advantage of this ‘trick’ (=describing visible features in terms of
equivalence relations):
We don’t need to bother about the essential
meaning of ‘red’ (just as we don’t need to bother
about the essential meaning of ‘three’).
In stead, we can concentrate on
•
interpretation of ‘is similar to’: kinds of similarities
•
identifying variants
•
identifying invariants
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From Light to Enlightenment
Introduction: what is an ‘image’?
There are many interpretations of ‘is similar to’
or ‘makes me think of’ (jigSaw!)
Common to all:
Every describable feature of an image is a
<here-this> pair,
Where ‘here’ denotes a location and ‘this’ is
some equivalence class.
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From Light to Enlightenment
Here is
cylindrical
Inleiding: wat is een beeld?
Here is bigger
than
Here is
saxofone
Here is bluewhite stripes
Here is tasteless
cliché (or: here is
recommendation
to buy porcellain
statuette)
Here is blue
Here is
ellipse
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From Light to Enlightenment
Image features in layers
Proposal: let us group ‘this’-s in groups
Groups have an ordering
Properties in group n ‘follow’ (or ‘build on’) properties in
group n-1
… in what sense ‘follow’?
Consider a process of visual communication, and study
coding and decoding
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From Light to Enlightenment
1.Come and
drink coffee
with me
2. Sequence
of characters
typed onto
keyboard
3. Bits en bytes
4A. Electrical
currents in wire
Kees van Overveld
virtual communication III
7.Meaning of the
message
virtual communication II
6. Letters
on a screen
virtual communication I
physical communication
5. Software
4B. Electronic
detectionn
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From Light to Enlightenment
representations:
Difficult to define, but:
•One representation can be converted into another
oen
•Can be replaced by other representations where
lower- and higher layers stay the same (variants!)
•Occur in a sequence of representation conversions,
together fulfilling some purpose (where invariants,
necessary for that purpose, stay the same)
•In images: any representation can be written out as a
series of here-this pairs
In the example:
Variants: color hue, reflectivity, thickness
of the border, …
Kees van Overveld
Invariants: color saturation, shape,
meaning,…
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From Light to Enlightenment
representations in the context of communication:
•1st sequence of representations: sender
•2nd sequence of representations: receiver
•Sender: initiates process with initial communication-impuls or
intention
•Receiver: concludes the process with understanding of (and
perhaps response to) the message
•Sender and receiver are connected with a physical link
•Virtual communications occur between any two intermediate
representations
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From Light to Enlightenment
1.
virtual communication
Representation
conversion
2. R
Representation
conversion
virtual communication
Representation
conversion
3. R’ encodes R
Kees van Overveld
6. R’ decodes R
Representation
conversion
virtual communication
Representation
conversion
4A.
7.
5. R
Representation
conversion
physical communication
4B.
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From Light to Enlightenment
Which layers form a layered communication
model for visual communication?
•Lower most: light rays (physical communication)
•Top most layer: intention and effect
Cause and/or
intentiong
The net effect of visual communication
Meaning and/or
effect
Emitting
light rays
Light rays
Reception of
light raysn
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From Light to Enlightenment
A 2-layer model is too naive:
•We need additional layers to talk about
•Representations in terms of …
•Colors, textures, shapes, surfaces, objects, relations
and meaning
•Representation conversions such as …
•Sending, reflecting and receiving light
•Sampling and discretisation
•Rendering and finding boundaries
•Interpreting 2D as projected 3D
•Understanding, recognizing and classifying objects
and relations among them
Kees van Overveld
•Therefore we propose 8 layers:
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From Light to Enlightenment
meaning
relations
objects
surfaces
shapes
texture
Color distributions
Light rays
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From Light to Enlightenment
Summary of essential concepts:
•Clustering: natural tendency of the brain
•Properties and values: features that cause clusters to occur
•Here-this pairs: an image as a collection of here-this pairs
•Equivalence: way to deal with the intersubjectivity-problem
•Equivalence classes: collection of indistinguishable values for a
given property
•Variants and invariants: what is lost, resp. preserved in
representation conversion
•Coding and decoding: takes place in sender and receiver,
respectively
•Physical and virtual communication
•Layers with representations and representation conversions
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