Temperature sensor for coordinate positioning apparatus

A coordinate measuring machine (10,12,14,16) carries a probe head (18), to which may be fitted a probe (20) for measuring a workpiece (24). An infra-red thermal imaging temperature sensor is mounted in or on the probe head (18), to determine the temperature of the workpiece, e.g. so that appropriate compensation may be made to the measurements to allow for thermal expansion. Alternatively, a separately-mounted thermal imaging temperature sensor (50) may be provided for determining the temperature of the workpiece (24).