ABSTRACT
As seen in the earlier chapters, one of the main problems in the application of radiation thermometry is the fact that very few real surfaces behave as black-bodies. In general their emissivities are much less than unity, and a sizeable correction needs to be made to the measured spectral radiance and hence to the indicated temperature. Moreover, in this situation it is possible for thermal radiation from other hot sources in the vicinity to be reflected from the target area into the thermometer, producing a second error. In this chapter we shall describe the techniques which may be employed to reduce these uncertainties. The topics of ratio and multiwavelength radiation thermometry which are also claimed to attack the emissivity problem have been covered in Chapter 7; here we shall deal mainly with single band radiation thermometers and the use of any additional information which may be ascertained for the system under study.
