Is your feature request related to a problem? Please describe.
apply_filter is used in SobelGradients to get the gradient map which needs a 'batch' dimension. In SobelGradients, it needs input with shape (batch, channels, H[, W, D]) which may be inconsistent with other post transforms.

Describe the solution you'd like
We may add a temporary batch dimension to the transform to make the transform more consistent, like: