Here's an overview of how Overviewer works.
Unfortunately, there isn't a similar Android app available right now that I'm aware of. However, I have been successful in sharing my Android screen through a USB cable with a free desktop program called Vysor.
Applications for Education
This could be a great app for anyone who has an iPhone or iPad and needs a document camera for online instruction. I haven't had a chance to try it yet this morning, but my plan is to use the Zoom annotation tools to highlight while using the Overviewer app in a remote lesson.