compare_images — IMGMETRICS report op

• Data kinds: image2d × image2d → metrics

• Call: import fullseye as fs; fs.ledger.compare_images(a, b, data_range=None, bins=64, channel_axis=None, ms=False) (to call the implementation directly, import imgmetrics; imgmetrics.compare_images(a, b, data_range=None, bins=64, channel_axis=None, ms=False); from the registry, opsimgmetrics.get("compare_images"))

Usage

Measure several metrics at once and return what was measured and how, alongside the numbers.

The return value's contract holds data_range / bins / crop_border / the SSIM window in order to prevent the conditions from disappearing when only the numbers are copied into a figure caption (a type of accident that actually happened in this repo).

Returns

dict

{"mse", "rmse", "psnr", "ssim", "mutual_information", "normalized_mutual_information", "ncd", "contract": {...}}.

With ms=True also ms_ssim (ValueError if the size does not allow it).

For colour images, passing channel_axis also adds delta_e_2000_mean.

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)

• image_quality_metrics — py -3.11 examples/image_quality_metrics.py

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

luma_limited_u8 · rank_data · tid2013_index · measure_with · metrics_table

Same category (report)

measure_with · metrics_table · data_range_of


*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.