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C00002 00002 COMPUTER VISION AND ITS RELEVANCE TO THE DEFENSE DEPARTMENT
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COMPUTER VISION AND ITS RELEVANCE TO THE DEFENSE DEPARTMENT
It is convenient to divide work in computer vision into
scientific work and work in basic technology. Scientific work is
aimed at getting certain knowledge, and basic technological work is
aimed at getting certain kinds of capability independently of how
this capability may be applied. In the field of computer vision, as
in artificial intelligence generally, these efforts are intertwined,
and it is often not clear which goal dominates in the work of a
particular group.
KNOWLEDGE
In computer vision, the main scientific questions are the
following:
1. What kinds of information about the world are available
through vision? Clearly only partial information about a person is
available from vision when you see him seated behind a desk. When
you see a machine at a distance even less information is available.
2. What information about the world can be assumed and
combined with direct vision information to get information about
three dimensional objects? What rules determine what can be
legitimately inferred or conjectured?
3. What is it reasonable to try to know about an object and
how can this information be represented in the memory of a computer?
Clearly this is different for a machine part whose complete shape is
often determinable and necessary and a tree or head of hair where it
is impossible and unnecessary to determine the location of each
individual hair or leaf. But note that a barber or tree surgeon
while not keeping in mind the location of all hairs or branches,
requires temporary information about particular hairs or branches in
order to do the next step of his work.
4. What information about a scene comes from the different
visual characteristics? What redundancy is there? By what rules
can the different cues be combined legitimately to give information
about a scene? The kinds of information that have been considered
include brightness and brightness edges, color and color edges,
texture and regions grown by combining small regions of homogeneous
texture, the distance as measured by range finders or by the
parallax of two views together with parallax edges. Recently there
as been a lot of work on so-called top-down approaches where a lot
of information about what objects may be presumed to be is used to
interpret lower level information. Thus if an object was presumed
to be a human, two and not more arms must be accounted for.
CAPABILITY
The main capabilities computer vision research is working
towards are the following:
1. The ability to find objects such as persons, vehicles,
or machine parts in a complex environment and to determine the
attitudes of the objects found. Thus we not only need to find the
vehicles in a scene but we also need to know which way they are
going. Machine parts must be located oriented so that manipulators
can pick them up.
2. The ability to give a description of a scene that is
complete with regard to those aspects relevant to a certain task.
APPLICATIONS
Computer vision has many potential applications including
some of special interest to the Department of Defense. Some of them
concern remote control and some concern automation of production.
I. REMOTE CONTROL
Before going into detail, it is necessary to mention one
major embarassment for the computer vision enthusiast. Namely, the
situation is somewhat analogous to early discussions of the
employment of computers for business and inventory purposes. Much
more elementary things than the employment of computers remained to
be done.
For example, at an early conference on possible applications
of computers in libraries, it was pointed out that a very large
improvement could be made without computers by adopting a proposal
made by Joseph Henry in 1859 for a uniform national cataloging
system.
An analogous role with regard to computer vision is played
by remote operation using television. There are still very large
payoffs for ordinary remote operation not involving computers.
However, just as with business and with libraries, there is also a
great potential payoff arising from the use of computers, and it is
not necessary to wait for all potential remote control payoffs to be
realized before beginning the study and even the application of
computer vision.
a. Remotely operated aircraft.
There are two reasons for wanting the ability to control
aircraft by computer as well as the ability to pilot it remotely
using television. First, communication cannot be guaranteed if the
aircraft is flying low or if there is jamming. To the extent that
we rely on remotely controlled aircraft, potential enemies will work
on jamming techniques.
Second, it may be possible to accomplish things with
computer vision that cannot be done by humans, specifically the
computer is potentially much faster than a person.
We see several tasks for vision in remote operation of
aircraft. The first is simply navigation. In particular, it seems
possible to write programs that will navigate by pilotage, i.e. by
comparing what it sees with a map. This would permit flight at very
low altitude through valleys and around buildings, etc. This
capability should be contrasted with that provided much more simply
by terrain avoidance radar in which the aircraft follows a fixed
ground track and avoids hitting obstacles by climbing when
necessary. It is not a priori clear how much application this
ability would have. It might be quite important if anti-aircraft
defenses develop in certain ways.
The second task is finding targets and controlling weapons.
This is an area where there is a potential very large gain over
human performance. Namely, suppose that it were possible to fire
many individually aimed shots per second. This would revolutionize
strafing, because it would then be possible to use much smaller
attack aircraft containing a much smaller amount of ammunition. Thus
there could be many more of them and the acceptable loss rates would
be much higher and the acceptable exchange ratios with targets could
be much lower. We believe that it is possible to recognize such
targets as people and vehicles, and it is possible to develop the
ability to decide in many cases which people are to be shot at
better than a person can do it in the heat of battle.
b. Remotely operated tanks.
We envisage these as small, inexpensive, and used in very
large numbers. The problem of automatically driving a ground
vehicle is more difficult than that of automatically piloting an
aircraft, because the variety of situations is greater. The problem
of automatically driving under combat conditions is easier than that
of driving a car. The reason is that almost all of the artificial
intelligence required to drive a car will be used to avoid accidents
under rare conditions. Combat vehicles will suffer high losses
anyway so that a few percent additional losses because the driving
programs are not very smart will not be of major importance.
c. Automatic sentries.
Here we get into an area where automatic methods have
probably got themselves a bad name because of the deficiencies of
the devices used in Vietnam. In our opinion, this is because an
attempt was made to be too clever, to use inadequate sensors, and
to rely excessively on algorithms for interpreting output of these
sensors which were not really general. We believe it is possible to
do much better, but we don't claim it is easy.
The application of computers to sentry duty arises from the
fact that humans have difficulty in paying continuous attention for
a long time when nothing is happening. Computers are quite good at
this. Moreover, automatic sentries can be posted quite far from the
unit they are protecting, and high losses will be acceptable. In
our view, an automatic sentry would consist of a computer, several
low light and infra red television cameras, whatever other sensors
might prove useful, communication back to base for pictures and
other data, and weapons that can either be fired as aimed from the
base or automatically according to the control of the computer. The
amount of discretion allocated to the programs would depend on
circumstances.
DEVELOPMENT OF THE MILITARY APPLICATIONS
The present organizational framework of unclassified
research in universities and other non-profit organizations is the
arrangement best capable of keepin the U.S. in the lead in basic
research and basic technology. Even though the U.S. work in these
areas is unclassified, our lead over other countries, especially the
Soviet Union has incrased. Classifiying the work would so reduce
the population available for thinking about the problems that our
lead would be slowed.
On the other hand, under present social and political
circumstances, these organizations are not suitable for developing
direct military applications. It will be necessary to monitor the
basic science and technology and decide when military applications
should be undertaken. Even the existence of these projects should
probably be classified.
II. NON MILITARY APPLICATIONS OF INTEREST TO THE DEFENSE DEPARTMENT
Besides direct military applications, there are many
applications of computer vision of that will help the Defense
Department do its work better. There is much interest in these
applications in the artificial intelligence community, and
capability generated in developing these applications will be
available for other uses.
In the main, these concern the need to be able to develop
hardware rapidly and to bring small quantities of equipment for test
into use as quickly as possible. The development of a general
mechanical assembly system and the further automation of other
aspects of production such as machining and forming will be aided by
computer vision and other AI systems. Of course, not every
application requires the most advanced methods, and the AI
researchers have recognized this. Indeed the Stanford and Edinburgh
assembly demonstrations, which are the most advanced at present, use
few technique which can be classified as artificial intelligence.
The fact is that the AI laboratories are also the most advanced in
real time control of experiments in a time-sharing environment, are
the most advanced in putting new applications into existing
time-sharing systems and are also the most advanced in conventional
programming techniques. Besides this, we are aware of the boundary
between AI and conventional techniques and are less likely than
others to get sucked into trying to do something the hard way when
experiment with AI is not the task being undertaken. We are not
sure how to document this claim of general competence, but we think
our visitors come away with that impression.