An apparatus for automatically aligning an infra-red sensor with a hot extruded body (28, 30), comprising: an infra-red sensor having an axis along which radiation is received; a scanner configured to move the infra-red sensor between a plurality of positions so that the axis of the infra-red sensor is pointed in a plurality of directions; and a processor configured to: analyse the amount of infra-red radiation received in the plurality of positions to determine an infra-red profile; identify a first position in which the axis of the infra-red sensor points at a first extruded body (28, 30) based on the infra-red profile; instruct the scanner to move the infra-red sensor to the first position so that the temperature of the first extruded body (28, 30) can be measured; instruct the scanner to move the infra-red sensor between a plurality of positions to either side of the first position; construct a second infra-red profile based on the radiation received in the positions either side of the first position; and determine if the extruded body (28, 30) has moved laterally based on the second infra-red profile, and if lateral movement is identified, the processor is further configured to instruct the infra-red sensor to move to a new position so that it can continue to point at the extruded body (28, 30). an infra-red sensor having an axis along which radiation is received; a scanner configured to move the infra-red sensor between a plurality of positions so that the axis of the infra-red sensor is pointed in a plurality of directions; and a processor configured to: analyse the amount of infra-red radiation received in the plurality of positions to determine an infra-red profile; identify a first position in which the axis of the infra-red sensor points at a first extruded body (28, 30) based on the infra-red profile; instruct the scanner to move the infra-red sensor to the first position so that the temperature of the first extruded body (28, 30) can be measured; instruct the scanner to move the infra-red sensor between a plurality of positions to either side of the first position; construct a second infra-red profile based on the radiation received in the positions either side of the first position; and determine if the extruded body (28, 30) has moved laterally based on the second infra-red profile, and if lateral movement is identified, the processor is further configured to instruct the infra-red sensor to move to a new position so that it can continue to point at the extruded body (28, 30). analyse the amount of infra-red radiation received in the plurality of positions to determine an infra-red profile; identify a first position in which the axis of the infra-red sensor points at a first extruded body (28, 30) based on the infra-red profile; instruct the scanner to move the infra-red sensor to the first position so that the temperature of the first extruded body (28, 30) can be measured; instruct the scanner to move the infra-red sensor between a plurality of positions to either side of the first position; construct a second infra-red profile based on the radiation received in the positions either side of the first position; and determine if the extruded body (28, 30) has moved laterally based on the second infra-red profile, and if lateral movement is identified, the processor is further configured to instruct the infra-red sensor to move to a new position so that it can continue to point at the extruded body (28, 30).