imaging - radar

cmk128@hotmail.com åAF«E9�93ïBC�


i got it :
http://www.newcon-optik.com/laser_monoculars.html

but how much is it? the website haven't tell

cmk128@hotmail.com ??:


i got it :
http://www.newcon-optik.com/laser_monoculars.html

but how much is it? the website haven't tell



Well, it's for sure not cheap: (> $300)
http://cgi.ebay.com/LRM-1000-Laser-Range-Finder_W0QQitemZ7222152824QQihZ015QQcategoryZ52509QQssPageNameZWD1VQQrdZ1QQcmdZViewItem

Greetz,
Stef?

That's not using stereo vision to calculate distance.  That's bouncing a
light beam off the object and uses the round trip time with and speed of
light in air to calculate distance.  That technique works much better than
stereo vision.  You can buy similar hand held units at sports stores for a
couple hundred dollars.  They are used for golf and hunting.  They work
fine but the accuracy is limited to about 1 meter at that cost (which is
fine for both golf and hunting).  The high end versions of the unit you
found at least comes with a computer interface which is useful if you are
going to try and use it on a robot.

You can also buy scanning laser range finders that work much better for an
application like robotics.  Just about all of the DARPA Grand Challenge
cars used them.  But they cost thousands of dollars.

With eyes set 6 inches apart can't calculate distance very accurately at
all.  It's been done using video cameras but it's a complex problem trying
to correctly identify matching objects in the two images to use the data to
calculate distance.

Humans get most of there distance information in other ways - not from raw
stereo data.  When we see a familiar object we know how far away it is just
by the size of the image compared to our past experience of seeing that e
type of object millions of times in the past.  When we look around our
environment, it is normally filled with tons of familiar objects all of
which our brain is able to give us rough estimates of distance on - even
with just one eye open.

Second, the brain makes heavy use of all the information in the temporal
data - how the picture is changing from second to second. As you move your
head from side to side the various objects in our view move - but they move
at different rates relative to each other based on there distance away from
us.  This allows the brain to use triangulation information with only one
eye but it's done by comparing the speed of motion of objects.  Same thing
is true for how the size of an object changes as it moves towards us and
away from us.  How quickly that size is changing tells us a lot about it's
distance away from us and it's direction of movement relative to us - once
again, using only one eye.  The extra stereo data we get from two eyes just
gives the brain that much more to work with.

The brain is very good at pickup up all these types of clues and others to
give us a very good sense of our surroundings.  Doing all that with
computers is still very hard.

--
Curt Welch                                            http://CurtWelch.Com/
curt@kcwc.com                                        http://NewsReader.Com/

Curt Welch åAF«E9�93ïBC�


Hi Curt Welch.
     You said our brain's "distance calculation" is based on our pass
experimence. Yes, i agree, but baby can catch thing very accurate by
their hand, so i think pass experimence is just auxiliary. Without it,
our brain still work.
    I saw "DARPA Grand Challenge" on the magazine, those car are using
laser beam to detect the road block, but it is too expensive. Is there
any cheap solution? i only need to detect the thing's distance within 5
meters.
thanks
from Peter

Ultrasound is the way to go for that distance - there are many inexpensive
units available. For shorter distances Sharp makes numerous inexpensive IR
sensors.

Mark

Curt Welch ??:


http://CurtWelch.Com/

http://NewsReader.Com/

Hi Curt Welch.
     You said our brain's "distance calculation" is based on our pass
experimence. Yes, i agree, but baby can catch thing very accurate by
their hand, so i think pass experimence is just auxiliary. Without it,
our brain still work.
    I saw "DARPA Grand Challenge" on the magazine, those car are using
laser beam to detect the road block, but it is too expensive. Is there
any cheap solution? i only need to detect the thing's distance within 5
meters.
thanks
from Peter

Babies have basically no hand-eye coordination at birth.  It can take them
6 months to learn to put food in their mouth.  They don't have the vision,
or the fine motor skills needed to do these things at birth.  It takes many
months of learning before a baby develops enough of a sense of the things
around and enough a sense of control over their own body to enable them to
reach out and grab something they see.


Sonar sensors are cheap (<$50) and some work to 5 meters.  But they are not
very directional or precise.

Here's one for example:

http://www.acroname.com/robotics/parts/R145-SRF08.html

Someone posted a message about their improved sonar sensors in this group
in the past month. Check old messages and you will find it.


--
Curt Welch                                            http://CurtWelch.Com/
curt@kcwc.com                                        http://NewsReader.Com/

here is the link to those improved sensors.
http://www.maxbotix.com/MaxSonar-EZ1___Others_Say_.php

Although I've doubts on several claims in this folder,
if I see the user responses, they must be very good.
I've to try these tricks once myself ;-)

Stef Mientki

True enough for a human baby, but many baby animals have both the vision
and motor skills for basic functioning within minutes of birth, and some
immediately upon birth. Dolphins are a good example of a fairly high
order creature babies can immediately swim, follow their mother, and
even find where to feed. Oddly enough birds, being far more dumb, need a
lot more parental care during their first week or so.

The comparison to humans is natural as that's what we are, but we're no
where near having an artificial brain that compares with humans -- most
lack the speech centers, opposable thumbs, and other eveolutionary
developments that mandate an increased learning curve. Being we can
hardly build a robot with the smarts of a cockroach, let along a human,
I think it's more realistic to concentrate on the processes of those
animals where instinct (basically preprogramming) supplants progressive
learning. The robot can still learn, but is at least minimally
self-reliant when the power switch is thrown.

-- Gordon

    It's not learning.  It's brain development.  Human brains aren't
fully grown at birth.

    We know this because there are animals that are ready to go
at birth.  Horses typically stand within an hour of birth and
can run with the herd the day they're born.  This is significant;
it indicates that the key locomotion and visual
systems don't start out blank.

    Some other animals are ready to go at birth.  Guinea pigs are,
but mice and rats are not.

                John Nagle

Split hairs. They aren't fully grown until at least 16-18 years old, and
even then, learning produces a constant development of the brain. It may
not always be physical growth, and the development not be as profound in
later years as infancy or childhood, but the brain is not a static
device even in adults.

Today even there was an article in the paper (San Diego Union Tribune,
but it's probably elsewhere) about how seniors who exercise their brain
have a better chance of avoiding the worst of Alzheimer's. They don't
fully understand the mechanism, but they noted being mentally active
even by doing something as simple as crossword puzzles appears to
*rewire* the brain around the Alzheimer-afflicted portions. On autopsy,
they found many of the mentally-stimulated seniors had significant
enough Alzheimer's calcification that would typically render the person
disabled, yet these men and women had only the occasional "senior
moment." That's clearly brain development from learning, and this in
70-80 year olds.

-- Gordon

Yeah, a lot of people like to talk about like that, however, brain
development based on sensory data is commonly called learning.


The fact that there are many lower animals that have systems that develop
without the need for sensory interaction does not prove anything about what
is happening in humans.  Humans need sensory interaction with an
environment to develop hand eye coordination as well as many other skills.
That's why this brain development in humans is commonly called learning.

--
Curt Welch                                            http://CurtWelch.Com/
curt@kcwc.com                                        http://NewsReader.Com/

(Peter)

No they can't. I've thrown dozens of things at infants,
and so far they just weep or look surprised.


(Curt)

This explains my experimental data!


(Curt)

IMO, 'lower' creatures, say, for example, spiders, come 'hardwired'
with a few
skillsets which allow them flourish in itheir intended envrionment.
Whether this
is by evolution or design is largely irrelevant. It is highly unlikely,
however, that
spiders will ever develop beyond these skillsets, at least in the
foreseeable
future. That is, the spiders of today will largely be the spiders of
your great-
grandchildren.

I would venture to say that are somewhat different creatures than
humans of one
or two hundred years ago, by virtue of culture and communication. 12
year olds
of today have mastered skills, technologies, and concepts which were
scarce
dreamt of 100 years ago. In some environments, the human learning
process
appears to be accelerated by the rapid proliferation of information,
and the
rapidity at which new ideas and concepts can be tried and tested.

Thus, in my opinion, roboticists face two broad paths they can travel
down-
adaptive learning systems, or hardwired reactive systems. There are
blends
of the two, but the distinction still exists. 'Classic' BEAM walkers
are, IMO,
a perfect example of the latter; experimental bipedal walkers are an
example
of the former.

At one time, I read of an individual who had worked out some sort of
'bitnet' score-based learning algorithm, implenting it using a PIC,
which also mimiced a BEAM core, which was coupled with a beam
style walker. This was an example of a blend.

Just my 2 cents,
         Tarkin

Depends on the bird.  A robin is born blind and helpless,
and needs to have food stuffed into its mouth.

But a chicken can run around and feed itself within an
hour of hatching.  That is a good thing too, because
many commercial breeds of chicken no longer have
any mothering instinct.

In addition to stereo vision for fast 3D perception most people still
have a strong sense of 3D when only looking through one eye.

This is because the brain does a size independent feature recognition
and association algorithm.  There as a discussion of an implemenation
of a size independed visual feature object detection and recognition
algorthim used in robots that let them have the ability to identify
all the objects in the room AND tell you how far away each one is.
It even automatically stitches together different views of the front
back and sides of objects that as it moves around it still recognizes
individual objects.

It could also recognize objects when only a part of the object was
visible when much of the object is obscured behind other things.
This is what humans and animals do.

The algorithm seems to be much better at recognizing real objects
in the real world and being able to understand and navigate or
deal with whatever individual objects in its environment that it needs
to recognize.

The human brain also applies a Gabor transform that fills in
visual information for the brain that the eye really never saw at all.
So what one 'sees' in the brain is not necessarily what the eye
saw.  This is not just visual illusions, but actual details of the
image that brain syntesizes.

So binocular vision is not as important for most things as the
ability to visually identify objects and remember them so that
they can be recognized from different angles, different distances
and with different parts of the image obscured, the way we do.

Your robot can tell you if you tennis shoes are next to it or
accross the room because it will remember how big they are
and what they look like from different angles if it is a reflex.

If you have radar or sonar and vision then you will need more
sensor fusion.

Auto-focus still cameras use only one "eye" and clever
(polarizing) optics

You can do it, but it's not easy. Look for 'stereo vision' or 'machine
vision' and you'll find that it's a well researched area. Check out
http://www.coyoterobotics.com/technology.htm  for one solution. I'm also
working on my version for my mobile robot, but I haven't published images
yet.

Regards,
Andras Tantos

    Actually, it's not that hard to do, but it doesn't work very well
in most visual situations.  There's code for doing it in the OpenCV
computer vision library on Sourceforge.  There's even code to
correct for camera misalignment, but about 10% of the time that code
produces a totally bogus correction.

                John Nagle
                Animats

OK, ok. What I meant was it's hard to do it right and fast.

Andras