Source MPP versus target MPP¶
MPP means micrometres per pixel: the physical tissue distance represented by one image pixel.
| Value | Meaning | CLI |
|---|---|---|
| Source MPP | Physical resolution of the input L0 image | --source-mpp in the main CLI; --slide-mpp in run.sh |
| Target MPP | Physical resolution requested for model tiles | Existing engine --mpp; default 0.5 |
They are not interchangeable. Target MPP tells the workflow how to resample once source scale is known; it cannot repair unknown source scale.
Use source MPP from, in order:
- scanner/export provenance from the imaging facility;
- a trusted sidecar generated by the export; or
- reliable embedded TIFF/OpenSlide metadata.
Generic TIFF DPI/resolution tags can describe display conventions rather than tissue scale. If the source scale cannot be established reliably, TumorQuantAI fails closed. Guessing a plausible MPP can silently change the physical field seen by the model.
The public tutorial manifest records source MPP 0.261780 for alias 022. That
verified dataset-specific value is not a universal default for other slides.
Both source and target MPP are recorded in summary/summary.json and
summary/run_metadata.json.
Next: read sampling and reproducibility.