Description
Explicit full pixel-footprint versus first-to-last pixel-center field-of-view convention.
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.
Explicit full pixel-footprint versus first-to-last pixel-center field-of-view convention.
When to use this tool
Use it for radiology image matrix field of view factor when the required inputs and conventions are already available.
How to use the tool and how it works
- Enter rows, columns, rowSpacing, columnSpacing, centerToCenter. Use the stated units and boundary conventions.
- Run the calculation. Correct any input error before interpreting a result.
- Read height, width, area. Inspect any known, defined, inclusion, or boundary flags before interpreting numeric values.
Require positive integer rows and columns and positive spacings. With centerToCenter false, multiply each count by its spacing; with it true, multiply count minus one by spacing. Multiply the two spans for area.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| rows | Rows | Required. Safe integer; minimum 1. |
| columns | Columns | Required. Safe integer; minimum 1. |
| rowSpacing | Row Spacing | Required. Finite number; strictly above 0. |
| columnSpacing | Column Spacing | Required. Finite number; strictly above 0. |
| centerToCenter | Center To Center | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| height | Height | Required. Finite number. |
| width | Width | Required. Finite number. |
| area | Area | Required. Finite number. |
{
"input": {
"rows": 100,
"columns": 200,
"rowSpacing": 0.5,
"columnSpacing": 0.5,
"centerToCenter": false
},
"output": {
"height": 50,
"width": 100,
"area": 5000
}
}Limitations and assumptions
- A one-pixel axis has zero center-to-center span but a positive pixel footprint. Row and column conventions must match the supplied spacings; no patient-coordinate orientation is reconstructed.
- 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 image matrix field of view factor, 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 Image Crop Origin Shift
Zero-based raster crop-origin translation with half-open bounds, not a patient-coordinate transform.
- DICOM Image Orientation Dot Orthogonality Gap
Check supplied DICOM row/column direction cosines for unit lengths and orthogonality using an explicit tolerance.