Description
Return one uniform etendue geometry term.
Spectral and radiation quantities depend on their denominator coordinates, reference levels and physical definitions. A density per wavelength changes by a Jacobian when expressed per frequency, and photon counts, radiant energy, exposure and absorbed dose remain different quantities.
Return one uniform etendue geometry term.
When to use this tool
Use Radiometric Etendue Area Solid Angle Factor when checking the stated spectral, photon, attenuation or radiometric conversion.
How to use the tool and how it works
- Enter area, solidAngle, cosine, refractiveIndex. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read etendue. Use the output convention below.
Return one uniform etendue geometry term. Require nonnegative area/solidAngle, cosine in [0,1] and refractiveIndex > 0; etendue = n²*area*solidAngle*cosine.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| area | Area | Required. Finite number; minimum 0. |
| solidAngle | Solid Angle | Required. Finite number; minimum 0. |
| cosine | Supplied projection cosine in [0,1], not an angle in degrees or radians. | Required. Finite number; minimum 0; maximum 1. |
| refractiveIndex | Refractive Index | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| etendue | Etendue | Required. Finite number. |
{
"input": {
"area": 2,
"solidAngle": 3,
"cosine": 0.5,
"refractiveIndex": 2
},
"output": {
"etendue": 12
}
}Limitations and assumptions
- Use a consistent area basis and steradians; a single supplied cosine approximates geometry rather than integrating a general optical field.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use a complete spectrum, measurement calibration and appropriate physical interaction model for integration, uncertainty or exposure interpretation.
References
Similar or alternative tools
- Radiant Intensity Isotropic Flux Factor
Convert uniform isotropic radiant intensity to total flux.
- Photon Number Density Energy Density Factor
Convert photon-number density at one supplied energy to energy density.