You'll find it under Basic Operations Module › Filters › Membrane detector. Its settings include:
- V-like and ᴧ-like: dark membranes on a bright background, and bright membranes on a dark background
- Custom Directions: the number of directions, then the angles searched, for example
4 | 0 90 45 135 - Min variation for V-like / ᴧ-like: a minimum variation threshold for each kind (default 0)
Several older parameters (rotation method, interpolation) are deprecated.