psnr — IMGMETRICS fidelity op

• Data kinds: image2d × image2d → scalar

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

Usage

Peak signal-to-noise ratio [dB].

For 2 perfectly identical images it returns inf (it does not add a small value to silently avoid division by 0 -- that would turn "a very good match" into a finite number and lie when you take an average).

For how to choose data_range, see data_range_of.

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

• poc_camera_shake_deblur — py -3.11 examples/poc_camera_shake_deblur.py

• poc_dehazing — py -3.11 examples/poc_dehazing.py

• poc_focus_stacking — py -3.11 examples/poc_focus_stacking.py

• poc_iqa_tid2013 — py -3.11 examples/poc_iqa_tid2013.py

• poc_real_deblur_honesty — py -3.11 examples/poc_real_deblur_honesty.py

• poc_superresolution_limits — py -3.11 examples/poc_superresolution_limits.py

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

luma_limited_u8 · rank_data · tid2013_index

Same category (fidelity)

mse · rmse · 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.