labkit.thermal.rawToTemperatureC

Description

Applies the FLIR Planck calibration stored in a radiometric image. The default correction also compensates for emissivity, reflected radiation, atmospheric transmission, and an infrared window. Select "planck-basic" when the raw counts have already been corrected or when only the camera's Planck constants should be applied.

Inputs

raw

Numeric array of raw sensor counts. The output has the same size.

calibration

Scalar structure containing the five required Planck fields and, for environmental correction, the fields described below.

opts

Optional scalar structure. See Options.

Calibration Fields

PlanckR1

Required finite scalar from the camera metadata.

PlanckB

Required finite scalar from the camera metadata.

PlanckF

Required finite scalar from the camera metadata.

PlanckO

Required finite scalar from the camera metadata.

PlanckR2

Required finite scalar from the camera metadata.

Emissivity

Object emissivity. Must be positive. Default: 1.

ObjectDistanceM

Camera-to-object distance in metres. Negative values are treated as zero. Default: 1.

ReflectedApparentTemperatureC

Reflected apparent temperature in degrees Celsius. Default: 20.

AtmosphericTemperatureC

Atmospheric temperature in degrees Celsius. Default: 20.

IRWindowTemperatureC

Infrared-window temperature in degrees Celsius. Defaults to ReflectedApparentTemperatureC.

IRWindowTransmission

Infrared-window transmission. Must be positive. Default: 1.

RelativeHumidity

Relative humidity as a fraction from 0 to 1 or as a percentage greater than 2. Default: 0.5.

AtmosphericTransAlpha1

First atmospheric alpha coefficient. Default: 0.006569.

AtmosphericTransAlpha2

Second atmospheric alpha coefficient. Default: 0.01262.

AtmosphericTransBeta1

First atmospheric beta coefficient. Default: -0.002276.

AtmosphericTransBeta2

Second atmospheric beta coefficient. Default: -0.00667.

AtmosphericTransX

Atmospheric mixing coefficient. Default: 1.9.

Options

Correction

String scalar selecting the conversion model. "environment" uses the environmental fields and records every fallback value. "planck-basic" uses only the five Planck fields. Default: "environment".

Outputs

temperatureC

Double array in degrees Celsius with the same size as raw. Pixels for which the Planck expression is undefined are NaN.

diagnostics

Scalar structure describing the conversion. correction is the selected mode; usedDefaults is true if an environmental fallback was used; defaultedFields lists those fields; parameterSources maps each environmental field to "calibration" or "default"; and message provides a readable summary. In "planck-basic" mode, no environmental fields are consumed and defaultedFields is empty.

Errors

Throws labkit:thermal:MissingCalibration when a required Planck field is absent or not finite, and labkit:thermal:InvalidOptions when Correction is not one of the two supported values.

Example

calibration = struct("PlanckR1", 21106.77, "PlanckB", 1501, ...
"PlanckF", 1, "PlanckO", -7340, "PlanckR2", 0.012545258);
raw = [15000 15500; 16000 16500];
[temperatureC, diagnostics] = ...
labkit.thermal.rawToTemperatureC(raw, calibration, ...
struct("Correction", "planck-basic"));