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Infrared thermometry remote sensing
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[QUOTE="ag123, post: 6029375, member: 648622"] thanks for the response ! :) i decided to make an attempt at a thought experiment making an attempted start from Stefan–Boltzmann law based on the clues from wikipedia [URL='https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law']https://en.wikipedia.org/wiki/Stefan–Boltzmann_law[/URL] [URL]https://en.wikipedia.org/wiki/Luminosity[/URL] $$ j*= \sigma T^4 \\ where \space T \text { is temperature at source in K } \\ L= \sigma A T^4 \dots (1) \\ where \space \sigma = 5.670373 \times 10^{-8}\, \mathrm{W\, m^{-2}K^{-4}} \\ irradiance \space per \space unit \space area \space E = \varepsilon L / 4 \pi r^2 \\ where \space r \text { is distance between source and probe } \\ and \space \varepsilon \text { is emissivity } < 1 \\ \text {power received at probe} \space P = a \varepsilon L / 4 \pi r^2 \\ where \space a \text { is cross section area of the probe facing the source } \\ \text{ substituting (1) power received at probe} \space P = a \varepsilon \sigma A T^4 / 4 \pi r^2 \dots (2) \\ \text { if we aggregrate the items which are basically constant } \space P \propto T ^ 4 / r^2 $$ i'm not too sure if the above is after all correct, but that if P (power received at probe) is $$ P \propto T ^ 4 / r^2 \\ where \space T \space \text {is temperature of source in K} \\ and \space r \space \text { is distance between source and probe} $$, it would seem quite possible to use a thermistor measure temperature at the probe) when temperature rises the energy would be conducted away or some emitted and reach some steady state temperature at the probe. this temperature could then be related to the source temperature remotely if i make a further simplifying assumption that the heat/power received at the probe is simply conducted away, and using the heat conduction equations [URL]https://en.wikipedia.org/wiki/Thermal_conduction#Integral_form[/URL] $$ \big. \frac{Q}{\Delta t} = -k A \frac{\Delta T}{\Delta x} \\ \text { substituting (2) } \space -k A \frac{\Delta T_p}{\Delta x} = a \varepsilon \sigma A T^4 / 4 \pi r^2 \dots \\ \text { and again aggregating the constant parameters } \\ \Delta T_p \propto T ^ 4 / r^2 \\ where \space \Delta T_p \space \text {is the temperature difference at the probe between the elevated temperatures and room temperature} \\ and \space r \space \text { is distance between source and probe} $$ this is rather curious and I'm unsure if it is correct if at all, but that if this make any sense at all it would imply that at the lower temperatures e.g. 0 deg C - 500 deg C we can simply measure the temperature at a probe remotely co-relate that to the source temperature being measured at a distance and hence measure / estimate the temperature of the source [/QUOTE]
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