Is your feature request related to a problem? Please describe.
For using the BilateralFilter layer (by @charliebudd ) more flexibly, I would really appreciate two extensions to the current filter implementation.

Describe the solution you'd like

1. It would be nice to implement the backpropagation of a loss into the filter parameters (spatial and range sigma) to be able to learn them directly.
2. In addition, independent spatial filter kernel sizes (sigma) for different spatial dimensions would be very interesting to have (Gaussian filter kernel can have a different size in different dimensions).