Method and device for contactlessly determining the temperature of a moving object having an unknown degree of emission

A device for contactlessly determining the temperature of a moving object having an unknown degree of emission, comprising:

• at least one radiation source emitting thermal radiation, of a known temperature;
• a guide apparatus by means of which the moving object is guided through the at least one radiation source, wherein the object is mostly or completely surrounded by the at least one radiation source;
• at least one radiation detector, which is designed to perform a spatially-resolved thermal radiation measurement in a region through which the object passes when it is guided through the at least one radiation source, wherein the at least one radiation detector detects the radiation of the at least one radiation source in addition to the object to be measured in its background;
• and
• an evaluation apparatus which is designed to determine the temperature of the moving object based on the spatially-resolved thermal radiation measurement by evaluating a difference between the measured thermal radiation emitted by and any reflected by the at least one radiation source, and the measured thermal radiation emitted and reflected by the moving object,
• wherein the at least one radiation source comprises a cavity radiator with an inlet opening and an outlet opening, wherein the guide apparatus is designed to guide the object through the inlet opening and the outlet opening through the cavity radiator, wherein the cavity radiator comprises at least one measuring opening, and wherein the at least one radiation detector is aligned such that the spatially-resolved thermal radiation measurement is performed through the at least one measuring opening,
• wherein the radiation detector for the spatially-resolved thermal radiation measurement detects a first region through the measuring opening in which the moving object is located below the measuring opening viewed perpendicular to its direction of movement, as well as a second region in which the moving object is not located below the measuring opening perpendicular to its direction of movement, and
• wherein the evaluation apparatus determines a position of the moving object using the measured values from the first region, and a position of the moving object in the second region is deduced therefrom, wherein the evaluation apparatus uses thermal radiation emitted and reflected by the moving object measured in this position of the second region to form the difference.