rmse — IMGMETRICS fidelity op

• Data kinds: image2d × image2d → scalar

• Call: import fullseye as fs; fs.ledger.rmse(a, b) (to call the implementation directly, import imgmetrics; imgmetrics.rmse(a, b); from the registry, opsimgmetrics.get("rmse"))

Usage

Root mean squared error (in the same units as the pixel values).

Formula: sqrt(mse(a, b)). Validation and failure conditions are the same as mse -- unless the shapes match / it is non-empty / finite, MetricContractError. Dimensionality and dtype do not matter.

• Return value: a Python float. If the input is float in [0, 1], the value is also in [0, 1]; for uint8 it is on the 0-255 scale. It reads as "how many grey levels off on average".

• It is a raw quantity independent of data_range, so placing the rmse of 2 pairs on different scales side by side is no comparison. If you need a normalised metric, psnr or ssim.

• For depth, CT, reprojection and other cases where "pixel value = physical quantity", it is in that physical unit itself.

Detailed usage guide

• image_difference_metrics family guide

References (sample data, literature)

• Sample-data catalog (download URLs / licences) — 2-D uses skimage.data (BSD/public domain) plus synthetic images; 3-D lists download URLs for real data sources (Stanford, PDS, …).

• Operator provenance and references — the sources of the research/methods this op family came from.

• The canonical algorithm (author, year) and its uses are named in the family usage guide above.

Runnable examples (verified samples that actually call this op)

• grasp_pose — py -3.11 examples/grasp_pose.py

• image_quality_metrics — py -3.11 examples/image_quality_metrics.py

• poc_ct_fidelity — py -3.11 examples/poc_ct_fidelity.py

• poc_datacenter_thermal_field — py -3.11 examples/poc_datacenter_thermal_field.py

• poc_polarization_specular — py -3.11 examples/poc_polarization_specular.py

• poc_structure_4d_deterioration — py -3.11 examples/poc_structure_4d_deterioration.py

Ops the type connects to (they accept scalar as input)

luma_limited_u8 · rank_data · tid2013_index

Same category (fidelity)

mse · psnr · ssim · ms_ssim · ssim_map

*Provenance: imgmetrics.py — IMGMETRICS operator registry. This per-op note is generated by tools/opdocs.py md (do not hand-edit).*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.