foe_from_flow — DRIVE `ttc` op

• Data kinds: image2d × image2d → table

• Call: import fullseye as fs; fs.ledger.foe_from_flow(u, v, mask=None, *, min_speed: 'float' = 0.3, max_speed: 'float' = inf, iters: 'int' = 5, angle_scale: 'float' = 0.05) -> 'dict' (to call the implementation directly, import drivettc; drivettc.foe_from_flow(u, v, mask=None, *, min_speed: 'float' = 0.3, max_speed: 'float' = inf, iters: 'int' = 5, angle_scale: 'float' = 0.05) -> 'dict'; from the registry, opsdrive.get("foe_from_flow"))

Usage

Estimates the focus of expansion (FoE) from optical flow: {"foe": (col, row), "n", "residual"}.

> The detailed description below is the original text — the summary and the headings are translated.

純平行移動の流れは FoE から放射状(Longuet-Higgins & Prazdny 1980)なので、各画素の流線(点 p_i を流れの向きに通る直線)は全部 FoE を通る。FoE = Σ w_i·dist(F, 流線_i)² を最小にする点(2×2 の正規方程式)。重みは反復で 1/|p_i − F|·1/(1 + (角度残差/angle_scale)²)(Cauchy 風)。遠い画素の流線ほど向きの誤差が FoE の位置に効くので距離で割り、外れ値(遮蔽・無地)を角度残差で落とす。15 巡目で「既知」にした FoE を流れから出す口(16 巡目)。

定理の門: 真の流れ(flow_from_depth_motion)を入れると foe_from_motion と 1e-9 で一致。

mask は使う画素(既定 = 有限で速さが [min_speed, max_speed] の画素)。有効画素が 3 未満、または正規方程式が特異(流線が全部平行)なら ValueError。

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_world_terrain — py -3.11 examples/poc_world_terrain.py

Ops the type connects to (they accept `table` as input)

course_layout · course_occupancy · course_contains · world_build · world_camera · world_move · lidar_scan · rss_longitudinal_same

Same category (`ttc`)

relative_motion · foe_from_motion · flow_from_depth_motion · ttc_truth · ttc_from_flow · ttc_from_scale · ttc_from_range · label_extent

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

foe_from_flow — DRIVE ttc op