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Coordinates system in Vuforia

May 13, 2013 - 3:22am #1

Hello.

I'm new at Vuforia and want to get camera pose relative to the target.

I found the method getPose, and it returns the target pose of the target.

Then, what coordinate system is the getPose method uses? Is it the camera coordinate system?? ( I guess....)

(Is this Unified coordinate system???? There are some track talking about UCS, but I don't know what it is exactly.)

I had test with a known target and extracted the 3X4 matrix return with the getPose of the TrackableResult.

I guess the left one is the base coordinate system. 

 

Is it right??

If it is not correct, please let me know about the base coordinate system of Vuforia or ....

In What coordinate system does getPose present the target pose?

 

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Coordinates system in Vuforia

May 14, 2013 - 3:23am #6

glad to help.

Coordinates system in Vuforia

May 14, 2013 - 2:49am #5

Yes, I think so. ^-^

Thank you for your answer. Your answer gave me a kind of conffidence.!

Coordinates system in Vuforia

May 14, 2013 - 1:46am #4

Hi, I cannot see the attached image (for some reasons the link appears to be broken);

however I think we are saying the same thing;

the only difference is that you are holding the device in landscape with the Home button on your left, while the default landscape mode is when you hold the device with the Back/Home buttons on the right (then you will see Y poiinting down, and X pointing to the right, as I said)

 

Coordinates system in Vuforia

May 13, 2013 - 7:33am #3

Thank you, AlessandroB!

I prepared something to know about Vuforia.

Values of pose are displayed on the overlay view. (Actually, My app's default orientation is landscape. )

On my way home, I had checked the test result. (as shown in attached image.)

 

The image I attached to the question was represent the default orientation is portrait.

To make my test result clear, I had better let you know that.

My app. do not allow view to rotate. It means my Camera (Coordinate system) is fixed with my device.

And default orientation is landscape (The home button is on the left)

 

Then, my result is different from your answer, I guess. 

The camera coordinate system has XY plane. The XY plane is perpendicular to the Line of Sight. And +Z direction is from EYE to the device.

You expressed it 'entering into screen'. I guess you said as what I think.

But, X and Y directions make me confuse.

My result shows that the +X points left and +Y points top when I see the device.

(If someone stare me in fornt of me, +X points his right and top still points top.)

 

In short, I'm in -Z and see +Z, and my left is +X and my top is +Y.

Is it reasonable???

 

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Coordinates system in Vuforia

May 13, 2013 - 4:57am #2

Hi, the getPose() method returns the reference frame of the target represented in the camera reference frame;

note:

the camera reference frame is defined with XY plane parallel to the screen and Z entering the screen;

the X-axis is aligned with the main dimension of the camera video frame, i.e. it points to the right if you hold the device in landscape mode, while the Y-axis points downward (again if you hold the device in landscape)

See also this article:

https://developer.vuforia.com/resources/dev-guide/pose-matrix-explained

 

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