gmsd_map — IMGMETRICS perceptual op

• Data kinds: image2d × image2d → image2d

• Call: import fullseye as fs; fs.ledger.gmsd_map(ref, dist, data_range: 'float' = 255.0, c: 'float' = 170.0, down_step: 'int' = 2) -> 'np.ndarray' (to call the implementation directly, import iqafsim; iqafsim.gmsd_map(ref, dist, data_range: 'float' = 255.0, c: 'float' = 170.0, down_step: 'int' = 2) -> 'np.ndarray'; from the registry, opsimgmetrics.get("gmsd_map"))

Usage

> This operator's description has not been translated yet. The original text follows as it is.

GMS 地図 (2 m_r m_d + c)/(m_r² + m_d² + c) ∈ (0, 1] (論文 式 3)。m = Prewitt([1 0 −1]×3 /3)勾配の大きさ、前処理は 2×2 平均 + 2 間引き

(:func:_average_downsample、原実装の 'same' 規約)。入力 (H, W) か (H, W, 3)(3-ch は Y = 0.299R+0.587G+0.114B、作者の慣例)。

Raises `ValueError`: 形が違う、c ≤ 0、down_step < 1。

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)

• poc_iqa_fsim_gmsd_vif — py -3.11 examples/poc_iqa_fsim_gmsd_vif.py

Ops the type connects to (they accept image2d as input)

mse · rmse · psnr · ssim · ms_ssim · ssim_map · image_entropy · joint_entropy

Same category (perceptual)

fsim · fsimc · fsim_pair · gmsd · vifp · phase_congruency_pc

*Provenance: iqafsim.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.