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Object Tracking in a 3D Space — Parallax Forums

Object Tracking in a 3D Space

David J BarnesDavid J Barnes Posts: 19
edited 2010-02-16 02:04 in Accessories
I suppose this belongs in the Sensors forum, otherwise feel free to relocate it.

I have a 3 dimensional space ~200ft(w) x 50ft(l) x 8ft(h). A person (or many at once) walk arbitrarily through the space. I would like to be able to track their "x,y" position in the space. While vision might be a viable option, I was wondering if the members of this forum might be able to offer some additional suggestions.

There are really no constraints other than the person could not carry excessive equipment. A small circuit would be perfectly acceptable.

Thanks in advance.
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Comments

  • LeonLeon Posts: 7,620
    edited 2010-02-08 23:44
    There is a technique using a pair of video cameras, but it needs a lot of processing power.

    Leon

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  • boeboyboeboy Posts: 301
    edited 2010-02-09 01:19
    You could make a grid of IR lasers in such a way that you could tell where the person is by where the beams are cut. I know that this idea is a little bit complex but it is the first thing that popped into my head. (Does that make me insane?) [noparse]:)[/noparse]

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  • CannibalRoboticsCannibalRobotics Posts: 535
    edited 2010-02-09 01:54
    How about a set of modified uSonic transducers. Put transmitters in the 4 corners and ping them sequentially in very regular time intervals. Use ping patterns that identify which transmitter you are listening too. After a couple of cycles you should be able to get a pretty good fix. Since it's one way and does not depend upon the reflectivity of the target or angle of the surface you should be able to get some pretty good range.
    All the target has to do is carry a 40KHz listening device and some processing power - Prop could do it.
    What's the update rate and resolution your wanting?
    Jim-

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  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 03:05
    Somebody said...
    You could make a grid of IR lasers

    No can do. We cannot alter the space that much. This was the first thing I thought of too.
  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 03:07
    CannibalRobotics- Can you be more clear on this "40khz listening device?" That sounds like what I am looking for...
  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 03:10
    CannibalRobotics- Oops. A 1Hz update would be perfect. Of course more is always better.
  • boeboyboeboy Posts: 301
    edited 2010-02-09 03:41
    After rereading the OP my idea will not work so well because if he is going to track more than one person my system will be easily confused.

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  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 03:44
    boeboy- Exactly. 1:m people roaming in a 200' x 50' space. The people can only wear some sort of minimally intrusive circuit (if needed). Color tracking would be tough since it would likely require the people to alter their apparel.

    I like the ideas so far though.
  • boeboyboeboy Posts: 301
    edited 2010-02-09 03:53
    David, how much can you change the space? Is it a wood or cement floor?

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  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 03:56
    boeboy- Completely static space. Dimensions as stated earlier with 4' high wooden walls at the perimeter. Although, if the design required the installation of a "track" or some suspended system above the space, that would be fine.
  • boeboyboeboy Posts: 301
    edited 2010-02-09 04:12
    Ok David if you have a black floor you could have everyone wear white hats and use a web cam to take pictures once a second (here is the spot that I am starting to guess) then you could have a software app puzzle out where the white pixels are in relation to the walls. Or you could use hats with IR leds.

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  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 04:14
    boeboy- Yep. I have done some interesting things with OpenCV doing object, pattern, and color tracking; but I am just not that confident. Plus, I'd rather not require them wear hats.
  • boeboyboeboy Posts: 301
    edited 2010-02-09 04:14
    But you would need more than one cameras if the roof is only 8 Ft tall. (Or one super fish eye lens )

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  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 04:15
    The 8' was incorrect. The vertical distance is substantial. Plenty of room for an overhead installation.
  • boeboyboeboy Posts: 301
    edited 2010-02-09 04:22
    If every person had a Ultra Sonic transmitter transmitting different data you could triangulate the signals. The only problem that I can see is with many people in the same room the acoustics could change very rapidly.

    BTW why do you need to keep track of these people? And what is the room for?

    Wow just stole CannibalRobotics idea. Sorry CannibalRobotics!

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    Post Edited (boeboy) : 2/9/2010 4:30:05 AM GMT
  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 04:25
    Can you elaborate on the Ultra Sonic transmitter? It's sort of an artistic installation a friend and I are working on. Sorry to with-hold info.
  • boeboyboeboy Posts: 301
    edited 2010-02-09 04:25
    David, Sorry about the seeming randomness of my posts I keep forgetting to refresh my browser to see if you have posted anything new.

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  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 04:28
    Quite alright. Just trying to get some fresh perspective.
  • boeboyboeboy Posts: 301
    edited 2010-02-09 04:30
    Ya I know what you mean. Now that I think about it my stolen (Sorry CannibalRobotics!) Ultra Sonic idea might not work so well because as I said if there are many people in the room it could get confused.

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  • boeboyboeboy Posts: 301
    edited 2010-02-09 04:33
    Wait you could do color tracking because all the software has to do is tell the difference between a colored spot and a black floor. (if the floor is black)

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  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2010-02-09 04:35
    David,

    Can you treat the detected humanity as an amoebic mass, or do individuals matter? In other words, if two people are standing very close together, do you need to recognize them as two people, as opposed to one of more profound carriage?

    -Phil
  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 04:40
    2, no more than 3 will be the in the space at once. 90% of the time only 1 will be present. When a second or third enter, they will be arbitrary and tracking should remain focused on person #1. In other words, tracking will only need to focus on person #1. Person 1-n are simply obstacles.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2010-02-09 04:57
    Hmm. That may seem to make it easier, but it actually makes it harder, since now the molecules (one of them anyway) are not only distinct but have labels. So if person one is approached by person two and they exchange an intimate greeting, then one of them walks off, you still need to know which is which. Right?

    And what happens when person one leaves the room? Does person two then become the new person one?

    -Phil
  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 05:02
    When person one leaves, the observation is complete. But like you said, if person 1 encounters person 2, then they split, tracking needs to remain focused on person 1.
  • boeboyboeboy Posts: 301
    edited 2010-02-09 05:05
    First of all once you are done I want to know what you are doing because this is intriguing shocked.gif. Well with that few people CannibalRobotics idea with the Ultra Sonic transmiters would work very well.
    David said...
    Can you elaborate on the Ultra Sonic transmitter?

    I had an image made to show you what I think CannibalRobotics meant but the Forums will not let me upload to night so i will try to talk it out.

    First for the transmitter part you have an ultra sonic emitter in each that send out a ping one after the other. Then you have each person with a receiver, the receiver consists of a prop, an Ultra Sonic receiver and an RF transmitter. The RF transmitter is for the props to transmit their position.

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  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 05:10
    Got a part reference for the us emitter and receiver? I am following this.

    I can piece together an x,y of the person by pinging each transmitter with precise timing? Will they reach 200'?
  • boeboyboeboy Posts: 301
    edited 2010-02-09 05:15
    Here is the part http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=139492 they are transceivers, but you will need to find something to drive them (again the prop will do it).

    Yes you should be able to find the exact spot where they are and you will always be able to tell were person 1 is. What do you mean by "Will they reach 200?"

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  • boeboyboeboy Posts: 301
    edited 2010-02-09 05:18
    David it has been great to talk with you but I need to get to bed I will check back in tomorrow, Oh never mind later on today LOL!

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  • David J BarnesDavid J Barnes Posts: 19
    edited 2010-02-09 05:19
    All- I am in the same boat boeboy. Maybe some new ideas will present themselves tomorrow. Thanks. Chat soon.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2010-02-09 05:29
    That pretty much rules out passive visual observation, then, unless person one is required to wear a beanie with a flashing LED atop it or some other means to make them stand out. Can you divulge what the actual application is? It might provide additional clues (that you may not have thought of) to facilitate a solution.

    -Phil
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