Forum

Some motion tracking questions

vvvv beta general
#1

hi there

great new site!

Im working on a patch where i want to ‘sense’ a room through motion tracking and use the tracking data to control parameters of the patch.

So i have a few questions regarding this:

So far ive managed to utilise the trautner freeframe to analyse movement. Im simply monitoring when there is a change in output values of the trautner and using this onchange to generate random numbers that are mapped to paramters which have an effect on the gfx.

Right now im using a 3chip dv cam in low light levels with slow exposure so i can pick up movement in the dark. When i go to set up the installation in a weeks time im told the room will be very dark and so i will have the use of a cam with nightshot or Infra-red.

Will the traunter still work with a cam with these settings? i will not have a chance to test before so id like to know if you can successfully use the traunter with infra red without any pitfulls.

Also i would like to know if there is a reliable way of tracking specific movement of bodies through a room with VVVV. What i really want to do is to track a room for movement and translate that in a meaningful way. A simple example would be that if a person moves across the camera field from left to right a quad moves from left to right too. Is this kind of operation possible, if so any leads?

#2

i’d say that infrared lighting does not per se cause problems with trautner. it could only occur that the image is more noisy. so probably you’ll have to adjust the thresholds.

for alternative motiontracking try the other FreeFrame filters and see how they work for your setup. they all have advantages and disadvantages for certain tasks.

#3

i think the contour tracker should be the right one.
it´s a blob tracker which returns the xy position and the boundary size of every tracked object. but it could be hard to adjust with a noisy image, may you have to do some image processing before.

#4

ok guys thanks for the tips, much appreciated.

i was intending to use the trautner as i like its speed and responsiveness, only i ran into a potentially bigger problem.

Its seems that my patches containing the trautner freeframe like to unexpectly crash after a few hours! ouch!

Ive tried testing on 3 machines and it does the same.

I remember reading a post about this somewhere in vvvvorums before but can seem to find it now.

anyone know if this can be solved?

essentially all im doing is using the trautner to sense greyscale changes hooked to a change node to trigger a
sequence of parameters.

#5

uh.

are you using the latest version shipping with beta10? we had those problems before but they were solved. i had trautner running in an installation for days without a crash.

#6

heh joreg

thankx for you reply - you seem to nearly answer all of my questions!

yeah im using version 10 and still it crashes after an hour or so. :(

I have to have this ready in a couple of days for a show, so any help greatly appreciated! :)

basically all im doing is using the cam to sense some change - not to actually track anything in the real sense. With the trautner im sampling one of the output slices to see when it changes from 0 to something and then using a change node to generate some random numbers. very simple.

perhaps there is another way of doing this with a different tracker?, i just cant work out how.

or is there anythihng else i can do to minimise these crashes?

many thanks

#7

You could try pipet and average the values and look for a change there? Not tried it though…

#8

zPH. can you describe the crash? the one i used to have (as mentioned above) popped up an error message and closed vvvv after hitting ok. what is happening with your patch?

also make sure you are using the latest camera-capture drivers and latest graphiccard drivers. what camera is it by the way (usb, firewire, analog-capture card)? what resolution are you caputring at? try lowering the resolution if possible. for sensing motion in areas even 160x120 could suffice.

#9

ok joreg,

the error im getting is the windows ‘this program has become unresponsive do you wanna send info about this error’…

sometimes tho, well just as often, vvvv unexpectedly crashes and intantaneously vanishes

it happens after 1 or 2 hours.

regarding the capture device, im using two and the same happens with both, one is a quality 3-chip dv cam connected via firewire. The other is a cheapo webcam connected via usb.

the gfx card is an ati x600 running the radeon omega drivers.

ill try and play around with the drivers i guess. and lower the res too.

thanks and praying.

#10

alo zPH, here is a small patch that should help you going with the pipet and your scenario.

SimpleTrautner.v4p (10.5 kB)

#11

great!

thanks for your time on that joreg :)

© vvvv group