Support spatio-temporal flow fields #112
Description
Currently, most flow field functions assume that the number of vector field channels is equal to the number of grid dimensions. However, in case of a spatio-temporal flow field, each vector field only deforms space.
The shape of a spatio-temporal flow field tensor is (N, D, T, ..., X), i.e.,
(N, 2, T, Y, X)for a 2D+t flow field, and(N, 3, T, Z, Y, X)for a 3D+t flow field.
Also the Grid would only apply to the spatial dimensions. The spacing between time points along the temporal dimension may need to be stored in a separate metadata field.
At the moment, one may need to use a sequence / batch of 2D or 3D flow fields instead, but computing a temporal partial derivative is then also not supported by the respective image functions.