maybe due to tracking history?

are you using ArDetectMarkers or ArDetectMarkersLite ?

ArDectectMarkers uses tracking history.  perhaps you should switch to
ArDectedMarkersLite after deactivating a marker (at least for a few
frames?).

brendan

----------------------------
|     Brendan Hannigan     |
|   brendan@c ............  |
----------------------------

On Thu, 10 Jul 2003, Emmanuel Dubois (IRIT) wrote:

> Hi,
> I have developped an application in which several patterns are tracked
> simultaneaously.
> But, I'd like to be able to ignore one pattern, while the others are still
> tracked, and then to track again this momentally ignored pattern.
>
> Looking in the .h files, I found the arDeactivatePatt which seems to be
> doing exactly that.
> BUT in fact, if the pattern is seen when I invalidate it (using the
> arDeactivatePatt) the pattern is still recognised (and data processed as if
> I havn't deactivated it).
>
> If I put my hand in front of the camera, then afterwards, the pattern is
> ignored until I reactivate it (using the arActivatePatt function).
>
> Any idea how I could solve this problem and avoid the need to hide the
> pattern I'm desactivating ?
>
> Thanks in advance.
> E.D.
>
> Emmanuel DUBOIS             ! Emmanuel.Dubois@i ......
> UPS - IRIT - LIIHS          ! www.irit.fr/recherches/LIIHS/dubois
> 118, route de Narbonne      ! Phone: +33 (0)5 61 55 63 59
> F - 31 062 Toulouse Cedex 4 ! Fax:   +33 (0)5 61 55 62 58
>
>

Hi,
I have developped an application in which several patterns are tracked 
simultaneaously.
But, I'd like to be able to ignore one pattern, while the others are still 
tracked, and then to track again this momentally ignored pattern.

Looking in the .h files, I found the arDeactivatePatt which seems to be 
doing exactly that.
BUT in fact, if the pattern is seen when I invalidate it (using the 
arDeactivatePatt) the pattern is still recognised (and data processed as if 
I havn't deactivated it).

If I put my hand in front of the camera, then afterwards, the pattern is 
ignored until I reactivate it (using the arActivatePatt function).

Any idea how I could solve this problem and avoid the need to hide the 
pattern I'm desactivating ?

Thanks in advance.
E.D.

Emmanuel DUBOIS             ! Emmanuel.Dubois@i ......
UPS - IRIT - LIIHS          ! www.irit.fr/recherches/LIIHS/dubois
118, route de Narbonne      ! Phone: +33 (0)5 61 55 63 59
F - 31 062 Toulouse Cedex 4 ! Fax:   +33 (0)5 61 55 62 58 

Thank you Brendan. With the ArDetectMarkersLite patterns are no longer 
recognised as soon as I deactivate them.
Nevertheless, the tracking is really damaged with ArDetectMarkersLite.

So I tried to call ArDetectMarkersLite just one time after deactivated the 
pattern and use the ArDetectMarkers afterwards. During the first event 
loop, the pattern is effectively ignored, but reappears just after (as soon 
as I reuse the ArDetectMarkers function) ... until it's really out of the 
grabbed video frame...

Is there a way to access to the "history list" of a pattern so that I could 
delete the history when I deactivate a pattern ? In this case I would be 
able  to permanently use the arDetectMarkers function and keep a good 
tracking quality.

Thanks for your help.

E.D.

At 11:33 10/07/2003 -0400, Brendan wrote:

>maybe due to tracking history?
>
>are you using ArDetectMarkers or ArDetectMarkersLite ?
>
>ArDectectMarkers uses tracking history.  perhaps you should switch to
>ArDectedMarkersLite after deactivating a marker (at least for a few
>frames?).
>
>brendan
>
>----------------------------
>|     Brendan Hannigan     |
>|   brendan@c ............  |
>----------------------------
>
>On Thu, 10 Jul 2003, Emmanuel Dubois (IRIT) wrote:
>
> > Hi,
> > I have developped an application in which several patterns are tracked
> > simultaneaously.
> > But, I'd like to be able to ignore one pattern, while the others are still
> > tracked, and then to track again this momentally ignored pattern.
> >
> > Looking in the .h files, I found the arDeactivatePatt which seems to be
> > doing exactly that.
> > BUT in fact, if the pattern is seen when I invalidate it (using the
> > arDeactivatePatt) the pattern is still recognised (and data processed as if
> > I havn't deactivated it).
> >
> > If I put my hand in front of the camera, then afterwards, the pattern is
> > ignored until I reactivate it (using the arActivatePatt function).
> >
> > Any idea how I could solve this problem and avoid the need to hide the
> > pattern I'm desactivating ?
> >
> > Thanks in advance.
> > E.D.
> >
> > Emmanuel DUBOIS             ! Emmanuel.Dubois@i ......
> > UPS - IRIT - LIIHS          ! www.irit.fr/recherches/LIIHS/dubois
> > 118, route de Narbonne      ! Phone: +33 (0)5 61 55 63 59
> > F - 31 062 Toulouse Cedex 4 ! Fax:   +33 (0)5 61 55 62 58
> >
> >

Emmanuel DUBOIS             ! Emmanuel.Dubois@i ......
UPS - IRIT - LIIHS          ! www.irit.fr/recherches/LIIHS/dubois
118, route de Narbonne      ! Phone: +33 (0)5 61 55 63 59
F - 31 062 Toulouse Cedex 4 ! Fax:   +33 (0)5 61 55 62 58 

From: Hirokazu Kato <kato@s ...................>
Subject: Re: pb with ARtoolkit function arDeactivatePatt
Cc: artoolkit@h ..................
Content-Type: text/plain; charset="us-ascii"

Hi,

>Is there a way to access to the "history list" of a pattern so that I could
>delete the history when I deactivate a pattern ? In this case I would be
>able  to permanently use the arDetectMarkers function and keep a good
>tracking quality.

Please look at 'ARToolKit/lib/SRC/AR/arDetectMarker.c'.
In this file, you can see functions 'arDetectMarker()' and
'arDetectMarkerLite()'.

There are very short codes. So by comparing them,
I think you can modify them for your purpose.

-- 
------------------------------------------------------------------
  Hirokazu Kato
  Graduate School of Engineering Science
  Osaka University                   Phone: +81-6-6850-6381
  Email: kato@s ...................     Fax: +81-6-6850-6341
  URL: http://www.sys.im.hiroshima-cu.ac.jp/people/kato/