are you currenty working all alone on touché? or is there any help for you?

i mean after all i’ve seen in touché and read from you in this thread there seem to be a lot of concepts and implementation behind touché. pretty much for one person.

chapeau!

lagerkoller - 04 November 2008 09:28 AM

are you currenty working all alone on touché? or is there any help for you?

i mean after all i’ve seen in touché and read from you in this thread there seem to be a lot of concepts and implementation behind touché. pretty much for one person.

chapeau!

heh, no, I’m alone unfortunately. But I hope that other developers will join my efforts in the future!

heh, no, I’m alone unfortunately. But I hope that other developers will join my efforts in the future!

we’ll see

meanwhile, i’ve got a few other issues:

- how do i get the dynamic background image calculation to work? i configured the pipeline in the way you can see in the image of my preferences at the end of the post. if i leave an object on the table the blobs of it never disappear. the same affects my hotspot. the only way i can change the background image is to untick Enable background subtraction and then tick it again. the background image seems not to be affected by Periodically update background image. have i configured something wrong?

- as you can see in in the image of my preferences at the end of the post i cannot see the whole rendering pipeline window on my mac mini system that uses the quite popular panasonic pt ax200 because the projector’s resolution with 1280x720 is not adequate. I would need a few more pixels vertically to see the Blob labelizer settings.

- if my mac mini goes to standby after the wake-up touché will not recognize any blobs anymore (the camera is showing the same image all the time). i fixed this issue by disabling the standby mode in the energy saving preferences. anyway, i can just restart touché after the standby. maybe a warning that it needs to be restarted would be cool.

basically, the dynamic background image calculation is crucial for me. especially if it is getting darker outside my hotspot will grow seriously within 10 minutes or so making it constantly necessary to leave my multitouch application and then to re-capture the background.

cheers,
johannes

my touché rendering pipeline preferences:

lagerkoller - 04 November 2008 02:59 PM

- how do i get the dynamic background image calculation to work? i configured the pipeline in the way you can see in the image of my preferences at the end of the post. if i leave an object on the table the blobs of it never disappear. the same affects my hotspot. the only way i can change the background image is to untick Enable background subtraction and then tick it again. the background image seems not to be affected by Periodically update background image. have i configured something wrong?

This isn’t how it’s supposed to work: When you select “Periodically update background image”, it will only snap a new background image when it is currently NOT detecting any blobs. That is, it is meant for gradual changes in ambient light, so that they can be accounted for in the background subtraction before they actually lead to false blobs.

If it snapped background images regardless, it would mean that if I put my fingers onto the touchscreen and don’t move them for a while, the touches would disappear because they’re being present in the new background image and subsequently subtracted. It only makes sense to snap a background image when it’s really a background without any foreground features, i.e. when there are currently no touches being tracked.

It’s true that there should be a “snap background image now” button, so I’ll add that to my list.

lagerkoller - 04 November 2008 02:59 PM

- as you can see in in the image of my preferences at the end of the post i cannot see the whole rendering pipeline window on my mac mini system that uses the quite popular panasonic pt ax200 because the projector’s resolution with 1280x720 is not adequate. I would need a few more pixels vertically to see the Blob labelizer settings.

Also probably something I should change. Touché was intended to be used with two screens, i.e. one screen you work on, configure stuff, probably develop on, etc..., and the second screen, which is the projector. Since all currently shipping Macs have at least 800 vertical pixels, I figured it would be fine.

lagerkoller - 04 November 2008 02:59 PM

- if my mac mini goes to standby after the wake-up touché will not recognize any blobs anymore (the camera is showing the same image all the time). i fixed this issue by disabling the standby mode in the energy saving preferences. anyway, i can just restart touché after the standby. maybe a warning that it needs to be restarted would be cool.

This is a known problem, but making it survive sleep&wake is really low on my list, because it is quite a lot of work, but pretty pointless, since I never intended Touché to be running when the Mac goes to sleep. Basically, I need to stop a lot of worker threads and relaunch them after wake, and things that aren’t already “sleep-aware” (i.e. non-Apple libraries like libdc1394) are even more problematic.

lagerkoller - 04 November 2008 02:59 PM

basically, the dynamic background image calculation is crucial for me. especially if it is getting darker outside my hotspot will grow seriously within 10 minutes or so making it constantly necessary to leave my multitouch application and then to re-capture the background.

Again, I don’t see how I could change the dynamic background subtraction from how it currently works to account for this, without risking it eating non-false blobs occasionally, too. If you have any suggestion though, I’m totally open to hear them!

I experimented in tbeta with this a bit.

I tried:

- updating the background all the time (adding in the current image to the background by a small percentage each frame)
- adding in the current image at a higher percentage only when no blobs and not updating when there were blobs
- a mix where if there were no blobs it would add more of the current image in and when there were blobs it would add at a slow rate.

I settled right now on just adding it in at a slow rate all the time, although i think the ‘mix’ worked better. You could have a slider that picks the rate and how much of the current image you want to be added. Yes, if you leave an object/finger in place for a minute or more without moving it’ll disappear, but that’s kind of what you want; you can assume anything that doesn’t move for a while isn’t meant to be there. This does pose a problem if fiducials end up being used (unless you have a separate stream for fiducials).

cerupcat - 04 November 2008 06:07 PM

I experimented in tbeta with this a bit.

I tried:

- updating the background all the time (adding in the current image to the background by a small percentage each frame)
- adding in the current image at a higher percentage only when no blobs and not updating when there were blobs
- a mix where if there were no blobs it would add more of the current image in and when there were blobs it would add at a slow rate.

I settled right now on just adding it in at a slow rate all the time, although i think the ‘mix’ worked better. You could have a slider that picks the rate and how much of the current image you want to be added. Yes, if you leave an object/finger in place for a minute or more without moving it’ll disappear, but that’s kind of what you want; you can assume anything that doesn’t move for a while isn’t meant to be there. This does pose a problem if fiducials end up being used (unless you have a separate stream for fiducials).

Sounds like good ideas, but what I do not agree on is that it is ok for a touch to disappear if it remains stationary for a while. However, I guess the best solution for me would be to add a checkbox labeled “update backgrounds despite tracked touches” or something, letting the user decide which behavior they prefer.

Blending the new background with the old background (with a slider to change the mixing ratio) is already something that Touché can do, so I suppose just allowing new background pictures to be snapped despite the presence of blobs is probably everything I need to add to provide for the flexibility you are describing.

Well you could also have a threshold where let’s say blobs above a certain size make it so it doesn’t update since you can assume those are fingers and not just noise. The problem is distinguishing whether it’s a finger or not and whether the user really knows enough to set that size. Of course we never want fingers to disappear, but it’s a pretty good assumption that if something the size of a finger or smaller doesn’t move at all then it’s probably not a finger. I’ve never had a user that didn’t move for 2 minutes straight.

I would also try doing it so the mixing ratio is higher when there are no blobs and then lower when there are blobs. That’ll help maybe get the best of both worlds. Just some thoughts.

cerupcat - 04 November 2008 06:30 PM

Well you could also have a threshold where let’s say blobs above a certain size make it so it doesn’t update since you can assume those are fingers and not just noise. The problem is distinguishing whether it’s a finger or not and whether the user really knows enough to set that size. Of course we never want fingers to disappear, but it’s a pretty good assumption that if something the size of a finger or smaller doesn’t move at all then it’s probably not a finger. I’ve never had a user that didn’t move for 2 minutes straight.

I would also try doing it so the mixing ratio is higher when there are no blobs and then lower when there are blobs. That’ll help maybe get the best of both worlds. Just some thoughts.

Yes, I suppose you’re right. Argh, I wanted to remove some filtering options in the future, but it looks as if I’m going to add more of them instead

haha, yeah I feel you. It’s hard to make things as simple as possible while also giving the user some options. Keep up the good work! I’m really liking how touche is coming along!

I’ve never had a user that didn’t move for 2 minutes straight.

cool: cerupcat said everything for me that i wanted to add to this discussion. i would highly appreciate the functionality to incrementally update the background image regardless if there are blobs on the screen or not.

Argh, I wanted to remove some filtering options in the future, but it looks as if I’m going to add more of them instead.

i understand you: Touché is offering tons of options and i really couldn’t dig in half of them. maybe information hiding would be a nice idea. maybe you could just put basic functionality in Configure Tracking Pipeline and hide the rest somewhere…

Added to Frameworks and Libraries Wiki. Please verify the info.

camilosw - 19 December 2008 09:45 AM

Added to Frameworks and Libraries Wiki. Please verify the info.

Thanks, the info is correct. I’ve only edited the entry to read Touché instead of Touche.