A method of operating a sensor device (10) in an interior (18) of a vehicle (16) for detecting at least one vehicle passenger-related physical quantity comprises steps of providing (70, 72) data sensed by the at least one sensor (12) and data sensed by at least one motion sensor device (14) that provides information regarding motion of a body (24) of the vehicle (16) as input data to at least one artificial neural network (48, 50, 52), carrying out (74) a combined deep learning scheme with the at least one artificial neural network (52), - generating (84) data of the at least one sensor (12) and data of the at least one motion sensor device (14) in a detection scenario, providing (86, 88) the data generated in the detection scenario as an input to at least one artificial neural network (52) trained by the combined deep learning scheme, and - by operating at least the artificial neural network (52) for processing the provided input data, derive (90) an output representing one or more vehicle passenger-related physical quantity or quantities, based on the carried out combined deep learning scheme.
