Description
One extrema-based uniformity convention 1-(max-min)/(max+min), with no modality acceptance threshold or automatic ROI selection.
An image grid has array indices as well as physical spacing, timing, and signal conventions. A calculation on supplied metadata describes one part of that grid or signal; it does not inspect an image, validate a complete file, or interpret anatomy.
One extrema-based uniformity convention 1-(max-min)/(max+min), with no modality acceptance threshold or automatic ROI selection.
When to use this tool
Use it for radiology phantom uniformity one pair term when the required inputs and conventions are already available.
How to use the tool and how it works
- Enter maximumSignal, minimumSignal, referenceMean. Use the stated units and boundary conventions.
- Run the calculation. Correct any input error before interpreting a result.
- Read absoluteRange, integralUniformity, referenceRelativeRange. Inspect any known, defined, inclusion, or boundary flags before interpreting numeric values.
Require maximumSignal at least minimumSignal, both nonnegative, with a positive sum and positive referenceMean. Return absoluteRange=maximumSignal-minimumSignal, integralUniformity=1-(maximumSignal-minimumSignal)/(maximumSignal+minimumSignal), and referenceRelativeRange=absoluteRange/referenceMean.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| maximumSignal | Maximum Signal | Required. Finite number. |
| minimumSignal | Minimum Signal | Required. Finite number; minimum 0. |
| referenceMean | Reference Mean | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| absoluteRange | Absolute Range | Required. Finite number. |
| integralUniformity | Dimensionless 1 minus the extrema range divided by their sum; not a percent. | Required. Finite number. |
| referenceRelativeRange | Reference Relative Range | Required. Finite number. |
{
"input": {
"maximumSignal": 110,
"minimumSignal": 90,
"referenceMean": 100
},
"output": {
"absoluteRange": 20,
"integralUniformity": 0.9,
"referenceRelativeRange": 0.2
}
}Limitations and assumptions
- This convention makes integralUniformity larger for a more uniform pair. The supplied extrema and mean are not extracted from an image, and no modality-specific acceptance criterion is applied.
- The field tables describe structural bounds; the mechanics also state cross-field requirements. Malformed input shapes, disallowed keys, and invalid domains cause input errors. Results must remain finite and within the declared output contract. A successful false flag or zero placeholder is distinct from an error.
- Numeric arithmetic uses binary floating point. Exact comparisons have no hidden tolerance or decimal rounding; negative zero is exported as zero. Decimal-text integer operations retain the exactness specifically stated above.
Alternative or Complementary methods
For radiology phantom uniformity one pair term, check the source records and the supplied rule before comparing the result with another method. Use a full image reader and geometry or signal analysis when the task requires interpreting image data.
References
Similar or alternative tools
- Radiology Phantom Contrast Noise Term
Phantom CNR using an explicitly supplied common noise standard deviation; no modality-dependent noise estimator or quality threshold.
- DICOM Study Series SOP Reference Pair
Compare explicit study/series parent references and construct a scoped instance key from an ASCII numeric UID subset, without resolving DICOM objects.