Visual Odometry to Estimate Position without GPS??

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Hi all,

Just wondering if anyone knows of alternatives to getting position
information without GPS? I have an indoor helicopter which I have
autonomously hovering, but it starts to drift because of drafts or the
IMU is not perfectly positioned (i.e. it's not exactly parallel to the
ground). Double integrating accelerometer data is prone to error
accumulation so that's not an option.

The only thing I can think of doing (excluding indoor GPS) is to point
a camera down towards the ground and use some sort of visual odometry
algorithm. If anyone else has any other ideas, I'd appreciate it.

If someone thinks visual odometry will work, I'd appreciate any advice
on the fastest way to successful implementation.

Thanks in advance!
-weg22


Re: Visual Odometry to Estimate Position without GPS??


<snip>

    You  might have a good idea there.  Look at the optical mouse on any
computer.  It uses a small cell count CCD camera chip.  They typically have
something like an 18x18 cell array.  That sounds wimpy but look at this
project link:

http://www.contrib.andrew.cmu.edu/~ttrutna/16-264/Vision_Project/

    I have a feeling that you could do something significant with this.

Cheers!

Sir Charles W. Shults III, K.B.B.
Xenotech Research
321-206-1840



Re: Visual Odometry to Estimate Position without GPS??


Or you can buy a miniaturized commercial version here:
http://www.helicommand.com/home_en.html
I was impressed that this idea went to market so quickly.
It would be nice if we could modify these devices to do
full-featured odometry (e.g. combine them with range sensors).

Re: Visual Odometry to Estimate Position without GPS??


...

Thanks for this interesting link..
Fred



Re: Visual Odometry to Estimate Position without GPS??




Directional ultrasonic rangefinders, with different frequencies?


Re: Visual Odometry to Estimate Position without GPS??


You might also find some interesting ideas, if nothing else, by Googling =
on "localization robotics". I stumbled upon "localization" on the =
Evolution Robotics website, and this group filled me in on what it =
meant. Sounds like the same sorta thing you need. Here's the Evolution =
link, just to get started: =
http://www.evolution.com/products/northstar/works.masn

Good luck !
JCDeen

Re: Visual Odometry to Estimate Position without GPS??


If the indoor area you are flying in is rather small, you could place a
planar visual target (with multiple easily detectable features) on the
floor, and use something techniques like homography to obtain vehicle
position and orientation. You might even be able to autonomously land a
helicopter using this approach!.

Try the following papers for a good description. You don't have to
implement the control approach presented in these papers if you don't
need to. You can definitely do the visual position estimation part:

See PDF of my paper from:
http://www.ces.clemson.edu/ece/crb/students/vilas/projects/landing/index.htm


A good paper on helicopter control using ground visual targets:
O. Shakernia, Y. Ma, T. J. Koo, and S. Sastry, “Landing an Unmanned Air
Vehicle: Vision Based Motion Estimation and Nonlinear Control,” Asian
Journal of Control, Vol. 1, No. 3, pp. 128—145, 1999

Vilas

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