Log in or register to post comments

Size of image target and hologram

June 7, 2020 - 6:27pm #1

Trying to develop an app for Hololens with Vuforia. I need to have smallest possible image targets. What is the smallest that image targets can be and be recognized reliably by Vuforia engine?

App is to display a 3D model based on image target. 3D models are created in Blender and imported into Unity. Need the hologram to have dimensions matching the 3D model's dimensions as reflected in Blender. As an example of size, one 3D model has dimensions 54 cm x 40 cm x 27 cm. 

What width do I need to specify for image target in online database on Vuforia developer portal if printed image is 8 cm wide? Should I use centimeters or meters for scale?

Currently the hologram looks like it is appearing behind the image target.

Size of image target and hologram

June 8, 2020 - 4:22am #2

Hi,

The Vuforia SDK extracts feature points from the marker with each camera frame. Thus, the more distant the marker becomes from the camera, the more difficult it will be for the algorithm to provide an accurate pose. You can estimate the minimum size that your target should have by dividing your camera-to-target distance by ~10. For instance, a 20 cm wide target would be detectable up to a distance of about 2 meters (20 cm x 10). Note, however, that this is just a rough indication and the actual working distance/size ratio can vary based on lighting conditions, device camera properties, and target rating. The latter point is covered in the following article: https://library.vuforia.com/articles/Solution/Optimizing-Target-Detection-and-Tracking-Stability

The Extended Tracking feature can be used to supplement our 2D tracker's performance and overcome some of these limitations. It also extracts features, from the environment in addition to the target, so may help to stabilize your experience.

In regards to the Target Manager, size is in meters.

Thank you.

Vuforia Engine Support

Log in or register to post comments