Facet Polish Line Visibility Rater
Audit measured polish-line contrast and instrument-resolvable width simultaneously under caller thresholds; not spatial RMS contrast or universal observer/commercial polish grade.
Description
Polish-line visibility depends on both contrast and resolvable width.
Polish-line visibility depends on both contrast and resolvable width. A contrast-only screen can miss a line narrower than the declared instrument resolution.1
Audit measured polish-line contrast and instrument-resolvable width simultaneously under caller thresholds; not spatial RMS contrast or universal observer/commercial polish grade.
When to use Facet Polish Line Visibility Rater
Use this tool to audit measured polish-line contrast and instrument-resolvable width simultaneously under caller thresholds; not spatial RMS contrast or universal observer/commercial polish grade.
Prepare the gemstone measurements, spectra or comparison data and any supplied calibration parameters. Check units, reference conditions and record alignment.
How to use Facet Polish Line Visibility Rater and understand its results
- Prepare the gemstone measurements, spectra or comparison data and any supplied calibration parameters. Check units, reference conditions and record alignment.
- Enter polishLineLuminance, adjacentFacetLuminance, callerRequiredMichelsonContrast, measuredLineWidthMicrometers, callerResolvableWidthMicrometers using the field table and calculation rules, then run the tool.
- Read observedLineMichelsonContrast, meetsCallerContrastAndWidthCriterion. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| polishLineLuminance | Polish line luminance | number | Required |
| adjacentFacetLuminance | Adjacent facet luminance | number | Required |
| callerRequiredMichelsonContrast | Caller required michelson contrast | number | Required |
| measuredLineWidthMicrometers | Measured line width micrometers | number | Required |
| callerResolvableWidthMicrometers | Caller resolvable width micrometers | number | Required |
Use nonnegative luminances with positive sum, nonnegative measured width, positive resolvable width and required contrast in [0,1]. Return contrast and a flag requiring both contrast and width to meet their thresholds inclusively.
Michelson contrast=|line luminance−facet luminance|/(line luminance+facet luminance) Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| observedLineMichelsonContrast | Observed line michelson contrast | number |
| meetsCallerContrastAndWidthCriterion | Meets caller contrast and width criterion | boolean |
{
"input": {
"polishLineLuminance": 2,
"adjacentFacetLuminance": 10,
"callerRequiredMichelsonContrast": 0.5,
"measuredLineWidthMicrometers": 10,
"callerResolvableWidthMicrometers": 5
},
"output": {
"observedLineMichelsonContrast": 0.6666666666666666,
"meetsCallerContrastAndWidthCriterion": true
}
}Limitations and assumptions
The thresholds are supplied. Observer response and commercial polish grading are not inferred.
Numeric inputs and returned numeric values must be finite; an unrepresentable returned value produces an error. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.
Alternative or Complementary methods
Use Contrast Pattern Grade Estimator: Grade measured spatial RMS luminance contrast under caller independent bands and physical patch areas; differs from temporal scintillation, no laboratory cut grade or perceptual preference is inferred. For a complementary task, use Eye-Clean Threshold Size: Compare already apparent inclusion width to caller visual angular-resolution model; real contrast, lighting, depth/refraction and observer acuity remain unmodeled, so this is not an eye-clean certification.
References
-
Facet Polish Line Visibility Rater — tool.io
Similar or alternative tools
- Contrast Pattern Grade Estimator
Grade measured spatial RMS luminance contrast under caller independent bands and physical patch areas; differs from temporal scintillation, no laboratory cut grade or perceptual preference is inferred.
- Eye-Clean Threshold Size
Compare already apparent inclusion width to caller visual angular-resolution model; real contrast, lighting, depth/refraction and observer acuity remain unmodeled, so this is not an eye-clean certification.