[comp.robotics] Noisy sensors

cphoenix@csli.Stanford.EDU (Chris Phoenix) (07/18/90)

I have a job in robotics research this summer, which covers everything from
Action Networks to the hardware.  My biggest headache at the moment is the 
sensors.  We have a laser rangefinder and a ring of infra-red sensors, and
all of them are quite noisy.  Being a theoretical CS person, of course I 
don't have the knowledge to deal with imperfect hardware.  So, any suggestions
and/or references would be appreciated.

The rangefinder projects a horizontal plane of laser light, and finds the 
range to the obstacle with a video camera mounted above the plane and looking
down into it (the laser projects a line on an obstacle, and the farther up 
the picture the line is seen, the more distant the obstacle is).  The IR 
sensors are just an LED and a photodiode.  Both sensors are jittery, and the
IR sensors also drift (as much as 30-50% in the raw data they return) over
a period of minutes.  The laser is too bright up close, and the line spreads
out to cover quite a bit of the picture.

So I can use suggestions or references on how to improve the hardware, or 
how to massage noisy data.  Thanks!

-- 
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buck@drax.gsfc.nasa.gov (Loren (Buck) Buchanan) (07/19/90)

In article <14484@csli.Stanford.EDU> cphoenix@csli.stanford.edu (Chris Phoenix) writes:
>So I can use suggestions or references on how to improve the hardware, or 
>how to massage noisy data.  Thanks!

Look at your basic signal processing texts as a starting point. (I'm also
a CS type and have little relevant experience).

I have a related question (which I am asking for others in my department),
and that is on the subject of classifying the data returned from a sensor.
We have a project to try and determine the cause of Gamma Ray Observatory
going into "safe hold" mode.  We get the recorded telemetry of some 200
sensors from the tape recorder dump and need to come up with classifications
for the data to then feed into an expert system.  Currently we are using
a neural net to do this classification.  My question is what should we
consider to be noisy data?  The other classifications we have are:
rising, steady, falling, trough, and peak.  What other classifications
should we think about adding?  

Thanks & B Cing U

Buck

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