Abstract: A non-contact infrared temperature sensing system for determining temperature values for a series of targets all having a similar emissivity value, which calculates an emissivity value for the targets based on the sensed total heat radiated from one target, an inputted temperature value for that target, and a temperature value for extraneous radiation from that target. The system then computes, for each subsequent target whose heat radiation is detected, a temperature value for each said target dependent upon the emitted component of radiation, and independent of the extraneous component of radiation from that target.

Abstract: A radiation detector has a dual element sensor. One sensor element detects thermal radiation of a target at the same time the second sensor element detects thermal radiation of a reference object adjacent to the target. The dual element sensor produces a signal of the difference in the sensed radiations. A remote meter displays the thermal difference and provides an indication of sensed mass of the target relative to the mass of the reference. The display is driven by a circuit which provides a fast response of the sensed thermal difference and a slow decay of the response to provide a somewhat continuous display between targets detected in a series. Alarms may be sounded in accordance with certain readings of the display. A continuously flowing, dynamic pattern of thermal differences is detected and displayed in applications of the detector to assembly line processes.