Ecological optic is concerned with many-times-reflected light in the medium, that is, illumination. Physical optic is concerned with electromagnetic energy, radiation. Ambient light coming to a point in the air is profoundly different from radiant light leaving a point source. The ambient light has structure, makes available information about reflecting surface. The information that can be extracted from ambient light is not the kind of information that is transmitted over a channel. There is no sender outside the head and no receiver inside the head.

1. THE INFORMATION FOR Haptic
PERCEPTION

2. The relationship between
stimulation and stimulus
information
• For visual perception, the information is
obviously light.
• For haptic perception, the information is
force.
• A number of similarities and differences
have been noted in the course of these
observations between active touch and
visual perception.

3. The distinction between Luminous
and Illuminated bodies
• Luminous bodies emit light: Light comes form sources such
as the sun, fire, or lamps.
• In ecological optics a reflecting surface is treated as if it
were a true surface having a texture.
• The distinction between radiation and illumination.
1. Directional radiation from the sun (direction variable with
time of day)
2. Scattering of the sun’s rays by particles in the
atmosphere(amount variable with atmospheric conditions)
3. Scatter reflection of the sun’s rays by the rough surface of
the earth
4. Diffuse illumination in the medium with omnidirectional
light (intensity variable with time of day)

4. The steady state of reverberating
light in an illuminated medium
under the sky

5. The distinction between radiant
light and ambient light.
• Radiation becomes illumination by reverberating between
the earth and the sky and between surface that face one
another.
• Such an omnidirectional flux of light could not exist in
empty space but only in an environment of reflecting
surfaces.
• The illumination reaches an equilibrium, that is, it achieves
what is called a steady state.
• The input of energy from the sun is just balanced by the
absorption of energy at the surface.
• Consider difference between radian light and ambient light:
Radiant light causes illumination, ambient light is the result
of illumination.
• Radiant light diverge from an energy source; ambient light
converges to a point of observation.

6. Radiant light from a point source
and ambient light to a point in
the medium

7. The structure of ambient light
• Ambient light has structure that specifies
the environment.
• The light at the point of observation has to
be different in different directions. (or there
have to be differences in different direction)
in order for it to contain any information.
• The term that will be used to describe
ambient light with structure is an ambient
optic array.

8. The structure of ambient force
the linear line complex (LLC)of an Instantaneous screw
Total Flux of stimulation

9. Stimulation and Stimulus
Information
• The difference between the retina and the eye is the difference between
receptors and a perceptual organ.
• There can be stimulus of a retina by light without any activation of the
eye by stimulus information.
• Receptors are passive, elementary, anatomical components of an eye.
• The traditional conception of sense is that the inputs of the nerves are
supposed to be the data on which the perceptual processes in the brain
operate.
• Actually, the eye is part of a dual organ, one of a pair of mobile eyes,
and they are set in a head that can turn, attached to a body that can
move from place to place.
• These organs make a hierarchy and constitute a perceptual system.
• Stimulus contains no information that brightness sensations are not
elements of perception, and that input of the retina are not sensory
elements on which the brain operates.

10. The concept of optical
information
• The concept of information with which we are
most familiar is derived from our experiences of
communicating with other people and being
communicated with, not from our experience of
perceiving the environment directly.
• We tend to think of information primarily at
being sent and received, and we assume that
some intermediate kind of transmission has to
occur, a “medium” of communication or a
“channel” along the information is said to flow.

11. The semaphore system
• The semaphore concept was invented by Dutch computer
scientist Edsger Dijkstra in 1962 or 1963,and has found
widespread use in a variety of operating systems.
• Then, the electrical telegraph, wireless telegraph, the
telephone, television, internet, and so on at the accelerated
rate of development.
• The ambient stimulus information available in the sea of
energy around us is quite different.
• The information for perception is not transmitted, does not
consist of signals, and does not entail a sender and a
receiver.
• The environment does not communicate with the observers
who inhabit it.
Dijkstra, Edsger W. Over de sequentialiteit van procesbeschrijvingen (EWD-35). E.W.
Dijkstra Archive. Center for American History,University of Texas at
Austin. (original; transcription) (undated, 1962 or 1963)

12. Optical Information
• The world is specified in the structure of the light that
reaches us, but it is entirely up to us to perceive it.
• The secrets of nature are not to be understood by the
breaking of its code.
• The information that can be extracted from a flowing optic
array, is a concept with which we are not at all familiar.
• We cannot explain perception in terms of communication, it
is quite the other way around.
• We cannot convey information about the world to others
unless we have perceived the world.
• And the available information for our perception is radically
different from the information we convey.

13. Summary
• Ecological optic is concerned with many-times-
reflected light in the medium, that is, illumination.
• Physical optic is concerned with electromagnetic
energy, radiation.
• Ambient light coming to a point in the air is
profoundly different from radiant light leaving a
point source. The ambient light has structure, makes
available information about reflecting surface.
• The information that can be extracted from ambient
light is not the kind of information that is
transmitted over a channel. There is no sender
outside the head and no receiver inside the head.