Device for contactlessly determining the straightness of at least one long product and method for calibrating a device of this kind

The invention relates to a device for contactlessly determining the straightness of at least one long product (103). Spot or linear measurement radiation (109) is moved over the long product (103) at least transversely to the longitudinal direction of the long product (103) by a radiation source module (106) during a measurement cycle. The intensity of the detection radiation (118) arising from the incidence area (115) of the measurement radiation (109) is recorded in a time-resolved fashion by means of a radiation detection module (121) and supplied to a control and evaluation unit (112). The location in space of the incidence regions (115) and hence the straightness of a long product (103) can be determined from location information regarding the incidence regions (115) in the longitudinal direction and from characteristic intensity values for the detection radiation (118). A reference straightness may be determined for calibration by executing a plurality of measurement cycles while rotating a long product (103) of unknown straightness.