This question is about 2 functionalities:
1) image recognition
2) image tracking
So I'm wondering is it possible to keep display object if recognized image or image tracking is lost? And update it's position if we recognized the same image again (and the same about tracking)?
Currently I'm using JS SDK but this question is about both JS and Native SDK.
You should test the Extended Tracking functionality. Extended tracking allows users, to recognize and track a target and the area around it. In this mode the Wikitude SDK will scan the environment of the user and try to keep track of the scene, even if the original target image is not in view anymore. For more information you can also refer here.