A splash-proof lid for a drinking cup has a splash guard in the form of a semi-permeable membrane positioned between the liquid contents of the cup and a discharge opening of the lid. One system includes an optical subsystem configured to acquire measurements of light scattered from the patterned features on the specimen at multiple angles of incidence, multiple azimuthal angles, and multiple wavelengths simultaneously. A support suspends the baffle from a tree or mounts the baffle to a pole in the ground.