Abstract: A patient monitoring system comprises a threshold determining unit configured to determine a cut-off threshold value based on a signal representing a reflection response of a skin of a patient and a signal representing a reflection response of a patient covering object. The patient monitoring system also comprises a signal processing unit configured to process a reflection signal, representing a detected wave reflected from at least a portion of the patient, based on the cut-off threshold value to cut off a portion of the reflection signal corresponding to detected wave reflected from the patient covering object to get a processed reflection signal corresponding to detected wave reflected from the surface of the patient.