We are trying to make a Spark AR filter for a conference that is triggered by scanning a specific poster on location. We have followed all the documentation on best practices for scanning said image, but the results are wildly unreliable and unreproducable. And sometimes it will start the filter but drop out without explanation.
The documentations suggests that you should slowly pan left to right in the image OR in a circular motion around the edges of the image. Both methods can take 10 minutes or more to register. We have tried old devices, new devices, apple, and android. And they all have the same struggle to recognize the image.
After much trial and error we found that:
Tracking (SLAM) requires the image to be visible to the camera until it is fully running - after that, you should be able to turn the camera away from the image and the effect will mostly still work.
You can get the image to Initialize reliably by slowly moving toward the image
Newer Phones initialize faster
Moving a device too quickly will cause you to lose tracking