Triple spectral area pyrometer

In a pyrometer that measures the temperature of a remote target having a known value of emissivity, said pyrometer having a means for receiving a target optical beam having a spectral width and a beam power including an emitted component and a reflected component, a detection module that divides said target optical beam into three optical sub-beams each having a subportion of the optical beam spectral width, said detector means for providing respective electrical signal equivalents of said divided optical sub-beams, a controller comprising:

• a signal processing means having a memory means for storing signals including signals indicative of a plurality of target temperature value signals corresponding to associated ones of a plurality of reflection corrected energy signal magnitudes for each one of said optical beam spectral width subportions and reflected energy signal magnitudes between said optical beam spectral width subportions;
• and
• a computation means for;
• selecting initial values of said ratios of reflected energy signal magnitudes between said optical beam spectral width subportions;
• computing target emitted beam power as a function of said measured optical beam power;
• calculating reflection corrected energy signal magnitudes as the difference signal magnitude between electrical signal equivalents of a second one of said optical sub-beam power signals and the product of a first one of said optical sub-beam power signals and a ratio of reflected power signal values in said first and second optical sub-beams;
• identifying, for each of said reflection corrected energy signal magnitudes, corresponding ones of said plurality of target temperature value signals;
• comparing a resolution temperature difference value signal with a signal corresponding to the difference between said identified target temperature signal values;
• and
• if said resolution temperature difference value signal is less than said identified target temperature difference signal value, providing output signals indicative of correct target temperature.

A detection module for use with an optical pyrometer that provides, along an optical guide, an optical beam having a spectral width, said detection module comprising:

• a housing having an interior cavity;
• first and second detector means for respectively providing electrical signal equivalents of long and medium wavelength portions of said optical beam spectral width, said first and second detector means positioned in the housing in registration with one another at a first end of the cavity and receiving the optical beam at a oPtically transparent portion thereof;
• a filter means for receiving and passing therethrough only a short wavelength portion of said optical beam, with the remainder thereof reflected from said filter means, and
• a third detector means registered with said filter means for providing electrical signal equivalents of a short wavelength portion of said optical beam;
• said reflected optical beam being presented to said second detector means at an inner cavity surface thereof, with only said long wavelength optical beam portion being transmitted therethrough to said first detector means.