Description
Return darkCorrected=measured-dark, relativeResponse=(measured-dark)/(reference-dark), and gainCorrection=target/(reference-dark).
Optical calculations distinguish lens power in diopters, prism notation, angular axes, geometric distances, and visual-acuity reporting scales. Sign conventions and length units are especially important when a formula combines power with decentration or vertex distance. A supplied model term is separate from a validated visual test or prescription.
Return darkCorrected=measured-dark, relativeResponse=(measured-dark)/(reference-dark), and gainCorrection=target/(reference-dark).
When to use this tool
Use Optometry Device Photometric Reference Gap when you need this explicit optical, chart, frame, axis, or reference conversion with compatible supplied units.
How to use the tool and how it works
- Enter measured, dark, reference, target. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read darkCorrected, relativeResponse, gainCorrection. Use the output convention below.
Require reference!=dark. Return darkCorrected=measured-dark, relativeResponse=(measured-dark)/(reference-dark), and gainCorrection=target/(reference-dark).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| measured | Measured | Required. Finite number. |
| dark | Dark | Required. Finite number. |
| reference | Reference | Required. Finite number. |
| target | Target | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| darkCorrected | Dark Corrected | Required. Finite number. |
| relativeResponse | Relative Response | Required. Finite number. |
| gainCorrection | Gain Correction | Required. Finite number. |
{
"input": {
"measured": 120,
"dark": 20,
"reference": 220,
"target": 100
},
"output": {
"darkCorrected": 100,
"relativeResponse": 0.5,
"gainCorrection": 0.5
}
}Limitations and assumptions
- Measured, dark, reference, and target need compatible photometric scales. Signed or above-one ratios are allowed; no sensor calibration is fitted, illuminance/luminance conversion inferred, or visual-test condition verified.
- 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 the appropriate complete optical or measurement model when a scalar term is insufficient. Verify power, axis, length, notation, and reference conventions before applying the result within a broader assessment.
References
Similar or alternative tools
- Lens Power Unit Reference
Compare supplied signed optical-power units to an explicit reference without a prescription or lens recommendation.
- Hearing Protector Bench Level Gap
Compare supplied bench sound-pressure levels without estimating wearer protection.