How can I convert tango point cloud data to worldspace point cloud?

Question

I am modifying the tango example point cloud app. I have exported point clouds along with its current pose data. The point cloud coordinates we get are relative to current pose. I wanted to know how can I convert the point cloud of different poses to worldspace coordinates (with respect to origin which should be first pose in this case)?

Answer 1

1 - Applying the pose transform to the pose points will give you world space coordinates

2 - If you're treating the very first pose as special (which I really wouldn't advise) then you are expressing your coordinates in the first poses coordinate system, not world coordinates. If you really want to do this (please don't, simply computing inverse transforms is far better) then I'd say you want to invert the first transform and keep it handy, and then multiply subsequent transforms by the inverse of the first transform (to cancel out the 'contribution' of the first) and then transform the points with the result.