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image detection

December 23, 2014 - 1:23am #1

i tried to detect an image target (Attachment :2-0-stampbw.jpg). When i scanned my image (but not full image,maybe about 20%-50% of the image. See attachment : 2-1-stampbw.jpg) then its already show my 3D model and it said that the image target was detected. its like Vuforia can predict the image even if half of the image didn't show in camera.. i want it show my 3D model after i scanned about 90%-100% of the image (full scan image).. cause i will have image like attachment : 2-2-stampbw_a.jpg. What can i do to fix this? please for your help, thank you.

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Image icon 2-0-stampbw.jpg109.46 KB
Image icon 2-1-stampbw.jpg44.84 KB
Image icon 2-2-stampbw_a.jpg83.72 KB
xinjelly
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image detection

December 26, 2014 - 12:33am #4

You're welcome

AlessandroB
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image detection

December 25, 2014 - 5:40pm #3

Hi, AlessandroB

thank you very much!!

xinjelly
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image detection

December 23, 2014 - 11:56pm #2

Hi, the image probably contains enough features so that Vuforia can infer the target from a part of it.

You cannot explicitely tell Vuforia to detect only when the target is fully visible,

however, you can add some application logic to "show / hide" your Augmentation model depending on the position of the target w.r.t. the view. For example, you could compute the position of the 4 target corners (points) in screen coordinates (i.e. projecting them from world space to screen space) by using the modelview and projection matrix (OpenGL) and determine whether the target is fully or partially visible in the camera view; based on this, your app code could then decide whether the augmentation should be rendered or not.

See also:

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

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

https://developer.vuforia.com/resources/dev-guide/screen-coordinates

 

 

AlessandroB
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