[PD] Body tracking

[Jaime Oliver]

> the truth is: it depends on the purpose.

Nothing Truer...

>> Not defending anything, but just to remind 60 fps of a pointgrey camera
is not slow.
>for gesture, i consider everything under 200Hz as slow.

surely this is the case for percussion as in your example here:

> by example, things like this have to be done at 1000Hz:
> http://vimeo.com/9598075

However, with a minimum of 75fps with a ps3 camera (you can get up to 120fps
at 320x240...) you can get very responsive results:
www.jaimeoliver.pe/sc2

It is clear that this project is not as concerned with precise triggers, it
is more concerned with continuous control...

you just need to find out if what these space&temporal resolutions offer you
what you're looking for. (+ solving less robust lighting, which is what
really determines if video tracking is the way to go...)

best,

J




>
>
>
> On Sun, Jan 9, 2011 at 12:37 AM, cyrille henry <ch at chnry.net> wrote:
>
>>
>>
>> Le 08/01/2011 20:24, Pedro Lopes a écrit :
>>
>>  Not defending anything, but just to remind 60 fps of a pointgrey camera
>>> is not slow.
>>>
>> for gesture, i consider everything under 200Hz as slow.
>> including the wiimote 100Hz.
>>
>> by example, things like this have to be done at 1000Hz:
>> http://vimeo.com/9598075
>> (we tried with slower system but it was not possible to be accurate
>> enough).
>>
>>
>>
>>  you probably will have a lot of trouble in dealing with 60 frames trying
>>> to cycle through your code every second.
>>>
>> you have problem analysing the image, but dealing with the data is no
>> problem.
>>
>>
>>  Accels and other hardware sensors are very useful too, and it very good
>>> results.
>>>
>> yep
>>
>>  But not the best for 3d positioning of a point in space,
>>>
>> they will not provide any information regarding 3d positioning.
>>
>>
>> the question is what information do you really want...
>> if you want the position of someone in space, then you have to use a
>> camera. but you can also track he's movement with a wacom.
>> if you want to track it's gesture, then you need something faster. faster
>> than a camera.
>>
>>
>>
>>  but excellent at giving the rotation of that point in space (i.e.:
>>> accels, gyros).
>>>
>> yep.
>>
>> cyrille
>>
>>
>>> :)
>>>
>>>
>>> On Sat, Jan 8, 2011 at 7:21 PM, marcello <wallacechemical at gmail.com<mailto:
>>> wallacechemical at gmail.com>> wrote:
>>>
>>>    On 08/01/11 14:25, cyrille henry wrote:
>>>     > hello,
>>>     >
>>>     > for the kung fu : movement are usually very fast. a camera is
>>> usually to
>>>     > slow to be useful.
>>>     >
>>>     > i personally prefer using sensor like accelerometter on the body.
>>>     > you can use wiimote or some other (faster) sensors system.
>>>     >
>>>     > here is a video of a performance i worked for few years ago.
>>>     > http://vimeo.com/4596629
>>>     > sensors are used at time : 4'57 to 6'06 and from 6'43 to 7'23.
>>>     >
>>>     > at 6'43, you can see that this kind of sensors are lot's more
>>> accurate
>>>     > that what you'll be able to do with a camera.
>>>
>>>    That's a good point about the sensors, I didn't know this
>>> camera-latency
>>>    problem.
>>>    WHat kind of sensor have you used in your work ?
>>>    Have you used wireless sensors ?
>>>
>>>     > imo, camera are good to track body position.
>>>     > kinect look to have a sensing zone that is a bit limited.
>>>
>>>    A combination of the two could be an idea, but then it's complicated
>>> to
>>>    merge the data...
>>>
>>>    Thanks for the infos
>>>
>>>
>>>    _______________________________________________
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>>>
>>>
>>>
>>> --
>>> Pedro Lopes (MSc)
>>> contact: pedro.lopes at ist.utl.pt <mailto:pedro.lopes at ist.utl.pt>
>>>
>>> website: http://web.ist.utl.pt/Pedro.Lopes
>>>
>>>
>>>
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>>
>
>
> --
> Pedro Lopes (MSc)
> contact: pedro.lopes at ist.utl.pt
> website: http://web.ist.utl.pt/Pedro.Lopes
>
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>


-- 
Jaime E Oliver LR

www.jaimeoliver.pe

858 750 0924 (cel)
858 202 1522 (home)
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