Transitions between panoramas in Three.js

Question

I have a set of peer images, I display them using sphere geometry with three .js similar to this example: http://mrdoob.imtqy.com/three.js/examples/webgl_panorama_equirectangular.html

I added buttons to the scene to allow navigation between panoramas. I would like to have a transition while traveling between panoramas. It should be like the transitions of Google Street View as much as possible.

Can someone share some ideas / tips on how to implement this using three.js?