A touch pad is controlled to detect a location of one or more objects (16) on a touch surface (15) of a transmissive element (12). The touch pad includes at least two scanning arrangements (24-26, 28, 29) which are configured as optical scanning transceivers. Each scanning arrangement is adapted to provide a beam of radiation along a pertaining direction (18) in the transmissive element (12), such that the beam propagates inside the transmissive element (12) by total internal reflection. Each scanning arrangement is also adapted to receive radiation from the transmissive element (12) and from the pertaining direction (18), and output corresponding signal. Each scanning arrangement is further adapted to scan the pertaining direction substantially along the touch surface (15). A processing element is arranged to determine, on the basis of the signals from the scanning arrangements, one or more positions on the touch surface (15) where scattering/absorption of radiation occurs as a result of the touching object or objects (16).