Log in or register to post comments

ImageTarget won't render Multiple Teapots

April 23, 2011 - 11:31am #1

Hi Guys, I only seem to get one teapot visible even when both trackables (chips,stones) are in view.
I have commented out the two lines in C++ code, and rebuilt project but no joy.
Could anyone have a look, as I have gone through entire forum...Thanks

Re: ImageTarget won't render Multiple Teapots

August 15, 2011 - 2:31pm #21

That's correct, currently there is no way to track a given target multiple times in the same view. This is a feature on the roadmap for future versions, however.

- Kim

Re: ImageTarget won't render Multiple Teapots

August 12, 2011 - 2:21am #20

@ksiva

so there's no way I can track the same target multiple times?
Is this a technical impossibility or is there a workaround?

thanks

Re: ImageTarget won't render Multiple Teapots

May 30, 2011 - 6:39am #19

Yep, good lighting is important for AR applications. Glad it's working now!

- Kim

Re: ImageTarget won't render Multiple Teapots

May 30, 2011 - 4:15am #18

Well sorry guys but now everything works with multiple Teapots in my Samsung Galaxy S. Last time I tried it was very dark (maybe that was the reason).

Regards!!

Re: ImageTarget won't render Multiple Teapots

May 27, 2011 - 6:31am #17

Could you give us some details, what is happening?

- Kim

Re: ImageTarget won't render Multiple Teapots

May 27, 2011 - 4:03am #16

The same happens to me.

I'm using a Samsung Galaxy S.

Re: ImageTarget won't render Multiple Teapots

May 20, 2011 - 2:32am #15

Thank you for replying so quickly!

I don't really have use case at the moment. I just try to discover the code of ImageTargets, and I was just wondering how I could repeat the same scene several times.

So, to sum up, if I have different targets, I can use HINT_MAX_SIMULTANEOUS_IMAGE_TARGETS and HINT_IMAGE_TARGET_MULTI_FRAME_ENABLED.

Re: ImageTarget won't render Multiple Teapots

May 19, 2011 - 11:55am #14

The system can only detect a single copy of the target at a time. Do not upload identical or similar targets in the same project, this will only cause issues with false positives. What is your use case, if I may ask?

You're correct, HINT_MAX_SIMULTANEOUS_IMAGE_TARGETS lets you track different targets simultaneously.

HINT_IMAGE_TARGET_MULTI_FRAME_ENABLED will break up the image processing over multiple frames. This can be important if you're trying to track a few image targets at once, otherwise the framerate might drop as the tracker does more work each frame. The downside is that it can take a few frames longer to initially detect a target.

HINT_IMAGE_TARGET_MILLISECONDS_PER_MULTI_FRAME is a way for you to suggest how many milliseconds to spend on detection/tracking each frame. Smaller values will increase your framerate, but comes at a cost of slower detection of new targets. Don't go too small or tracking may stop working altogether! Most of the time you don't need to change this from the default, but the option is there if you want to play with it.

- Kim

Re: ImageTarget won't render Multiple Teapots

May 19, 2011 - 9:36am #13
ksiva wrote:

That shouldn't matter. Do you have one stones and one chips target in front of you? You can't track multiple copies of the same target.

- Kim

Well, I have two questions...:confused:

1) Why is it impossible to track multiple copies of the same target? Because each trackable has a unique identifying?

What if I want to try to track multiple copies of the same target? Do I have to create multiple copies of the same trackables in my Online Trackables Project? They will all have a different id, and I just have to put the same render for ecah one...

2) If I well understood, HINT_MAX_SIMULTANEOUS_IMAGE_TARGETS allows to track multiple DIFFERENT targets... (I tried it just uncommenting this line, and it works)

But I don't understand what is HINT_IMAGE_TARGET_MULTI_FRAME_ENABLED

I know you have an API, who explains that...
Enables splitting the detection of new image targets over multiple frames This hint tells the tracker that detection of currently untracked image targets shall be split over multiple frames. The tracker will therefore require less time per frame but longer to find new targets. Default value is 0 (no multi-frame detection).

...but I don't understand. Could you please give an example to explain?

..and an other for this one : HINT_IMAGE_TARGET_MILLISECONDS_PER_MULTI_FRAME ? :D

Thanks!

Re: ImageTarget won't render Multiple Teapots

May 12, 2011 - 9:21pm #12

Kim, my ImageTargets Finally can detect multiple markers, but i have to wait long before my second object appear in camera. Maybe my object size is too big.

Thanks,

Gyan

Re: ImageTarget won't render Multiple Teapots

May 11, 2011 - 5:10pm #11

You may want to try printing the targets out smaller, the camera resolution might not be good enough to pick out the details with both images in view.

- Kim

Re: ImageTarget won't render Multiple Teapots

May 11, 2011 - 4:36pm #10

my device is Samsung Galaxy Mini ( GT-S5570 ), OS 2.2 ( Froyo ). please solve my problem..thank you..

Regards,

Gyan

Re: ImageTarget won't render Multiple Teapots

May 11, 2011 - 2:13pm #9

You just need to be able to get a good portion of both targets in view at once.

What device are you using? We can try testing with the specific device if we have one on hand, but it should work across all compatible devices.

Make sure that your changes to ImageTargets.cpp are really getting pushed to the phone. Try adding a LOG statement and checking DDMS as a sanity check.

- Kim

Re: ImageTarget won't render Multiple Teapots

May 11, 2011 - 9:19am #8

yeah, i have the chips and stones targets. how about the distance?did the distance between camera and the targets can affect imagetargets to detect multiple targets??

Re: ImageTarget won't render Multiple Teapots

May 11, 2011 - 8:30am #7

That shouldn't matter. Do you have one stones and one chips target in front of you? You can't track multiple copies of the same target.

- Kim

Re: ImageTarget won't render Multiple Teapots

May 11, 2011 - 8:26am #6

i do just like you said above, but it wont multiple teapots??did the phone type affect this??my android doesnt have an auto-focus or flash..

Re: ImageTarget won't render Multiple Teapots

May 11, 2011 - 8:11am #5

Hmm, you're sure you uncommented those lines and rebuilt with ndk-build? Refresh the Eclipse project, and also try cleaning the Eclipse project just to be sure (Project > Clean).

Make sure both targets are clearly in view, set them side-by-side and move the camera around. Try getting a lock on one then panning to the other to get a lock on it.

- Kim

Re: ImageTarget won't render Multiple Teapots

May 11, 2011 - 8:03am #4

Image Targets wont render multiple teapot even after i follow your instructions kim..why??

help me..

regards,

Gyan

Re: ImageTarget won't render Multiple Teapots

April 30, 2011 - 4:40pm #3

Thanks Kim, makes total sense now!! I thought the JNI Libraries would be built in eclipse, but sure why would we need Cygwin!!

Re: ImageTarget won't render Multiple Teapots

April 24, 2011 - 10:29pm #2

Hmm, it should just be a matter of uncommenting these lines:

QCAR::setHint(QCAR::HINT_MAX_SIMULTANEOUS_IMAGE_TARGETS, 2);
QCAR::setHint(QCAR::HINT_IMAGE_TARGET_MULTI_FRAME_ENABLED, 1);

Then rebuild using ndk-build. You may need to refresh the project in Eclipse (right-click in the Package Explorer and choose Refresh) before building and running.

Make sure you're getting the center of both targets in view. That's the easiest way to lock on, then you can track smoothly between the two.

- Kim

Log in or register to post comments