I have been reading the documentation and playing with Eigen recently:
and would like to build something that uses it extensively to learn it well. I looked on their website and they mention various projects that use it - like Google Ceres. Something like that might be too large for one or two people to undertake on the side as an Eigen learning experience so I'm looking for something simpler but not trivial that would use it extensively and is a real - useful - application..
Eigen is extensively used in computer vision, and if you are comfortable with linear algebra and matrix calculus (I assume you are, otherwise you wouldn't use Eigen), why not build a toy VSLAM (visual simultaneous localization and mapping) system? Those that are based on bundle adjustment (there's a whole chapter dedicated to that in zisserman's book on multipleview geometry, and it is also discussed in the open-source yet excellent book enter link description here) can be very tricky to implement efficiently, and will take a lot of time, but since your goal is to learn Eigen, performance shouldn't be that much of an issue. If that seems too hard/long for two people, and you think it demands too much energy for a side-project, I recommend that you select some computer-vision algorithms like those that compute the the essential matrix between two images, or are used in 3d pose estimation. Well, those are the only really fun things that come to mind right now, and they will force you to discover a lot of Eigen's functionalities (and gotchas!).
