Description
Return ridge spacing and its reciprocal density.
Biometric research records separate subject IDs, template dimensions, image geometry, enrollment support and attempt budgets. Local counts and comparisons can reveal inconsistencies without reading biometric templates, detecting a physical trait or authenticating a person’s identity.
Return ridge spacing and its reciprocal density.
When to use this tool
Use Fingerprint Image Ridge Spacing Factor when checking the stated biometric record, count, support, geometry or budget convention.
How to use the tool and how it works
- Enter distancePixels, intervals, pixelsPerMm. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read meanSpacingPixels, meanSpacingMm, ridgesPerMm. Use the output convention below.
Return ridge spacing and its reciprocal density. Require positive pixel distance, pixelsPerMm and whole intervals >= 1; mean spacing divides distance by intervals and calibration, ridgesPerMm is its reciprocal.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| distancePixels | Distance Pixels | Required. Finite number; strictly above 0. |
| intervals | Whole number of ridge-spacing gaps over distancePixels, not necessarily number of ridge lines. | Required. Safe integer; minimum 1. |
| pixelsPerMm | Pixels Per Mm | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| meanSpacingPixels | Mean Spacing Pixels | Required. Finite number. |
| meanSpacingMm | Mean Spacing Mm | Required. Finite number. |
| ridgesPerMm | Ridges Per Mm | Required. Finite number. |
{
"input": {
"distancePixels": 100,
"intervals": 10,
"pixelsPerMm": 20
},
"output": {
"meanSpacingPixels": 10,
"meanSpacingMm": 0.5,
"ridgesPerMm": 2
}
}Limitations and assumptions
- Intervals must count gaps rather than ridge endpoints consistently; no fingerprint ridge detection or identity comparison is performed.
- 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 verified acquisition/enrollment records and the complete appropriate format and evaluation process for actual identity, quality, capacity or privacy decisions.
References
Similar or alternative tools
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