Two-color, two-dimensional pyrometers based on monochrome and color cameras for high-temperature (>1000 K) planar...

Two high-temperature 2D-pyrometers are described in this work. They are, respectively, based on the comparison of light intensities received by two monochrome cameras with narrow filters and the different color channels in a single color camera. The calibration procedure includes tests with thermocouples in flame flue gases and with a light bulb filament in the range 1050 K-2650 K, although the upper limit may be reliably extrapolated in the two-camera pyrometer. This device shows smaller uncertainties in absolute temperature determination than the other, ∼±15 K in the calibration curve. A combination of the two-color technique with intensity pyrometry is shown to allow the quantification of differences of the order of 1 K for uniform emissivity surfaces. Several examples of application of both pyrometers are presented to assess their spatial resolution and thermal capabilities, including the contact between the hot filament and its support in the light bulb and fine-wire thermocouples with large bead/wire ratios. The optical systems were designed for their use at short working distances and with high spatial resolution (4.7 μm/pixel and 8.7 µm/pixel) but could be adapted to other scenarios.