Description
Scale supplied skin-image pixels using a physical scale bar.
Dermatology records distinguish specimen sites, image permissions, orientation, scale references, area models and observation states. Full ellipse axes differ from radii, and rectangular area estimates need not match a lesion or wound. Supplied labels and scalar image measurements do not establish clinical findings or appropriate care.
Scale supplied skin-image pixels using a physical scale bar.
When to use this tool
Use Skin Photo Scale Bar Pixel Ratio when you already have scaleBarMillimeters, scaleBarPixels, measuredPixels and need to scale supplied skin-image pixels using a physical scale bar.
How to use the tool and how it works
- Enter scaleBarMillimeters, scaleBarPixels, measuredPixels. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read millimetersPerPixel, measuredMillimeters. Use the output convention below.
Require scaleBarMillimeters and scaleBarPixels>0 and measuredPixels>=0; return mm/pixel and measuredPixels*barMillimeters/barPixels.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| scaleBarMillimeters | Scale Bar Millimeters | Required. Finite number; strictly above 0. |
| scaleBarPixels | Scale Bar Pixels | Required. Finite number; strictly above 0. |
| measuredPixels | Measured Pixels | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| millimetersPerPixel | Positive scaleBarMillimeters/scaleBarPixels, a linear image factor. | Required. Finite number. |
| measuredMillimeters | Measured Millimeters | Required. Finite number. |
{
"input": {
"scaleBarMillimeters": 10,
"scaleBarPixels": 200,
"measuredPixels": 350
},
"output": {
"millimetersPerPixel": 0.05,
"measuredMillimeters": 17.5
}
}Limitations and assumptions
- Linear calibration and shared image scale are assumed. No image detection, lens/perspective correction, lesion classification or actual measurement accuracy is established.
- 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
Review the original clinical, specimen and image records with verified calibration and consent context. Use the complete appropriate assessment for interpretation; local geometry, display labels and reporting conventions do not identify a lesion, diagnose disease or choose treatment.
References
Similar or alternative tools
- Plaque Disclosure Image Scale Ratio
Convert a supplied plaque-image distance by a physical reference scale.
- Organoid Diameter Scale
Convert an organoid's supplied pixel diameter with a linear image scale.