Edge-Shape (Chamfer) Template Matching

Intensity correlation (visual_match) is dragged down when the same control is rendered with a different fill, gradient, theme or anti-aliasing, and ORB feature matching (feature_match) needs corner texture that flat-design glyphs — a hamburger menu, a plain chevron — simply do not have. edge_match locates a template by its edge shape instead: it runs Canny on both images, builds a distance transform of the scene edges, and slides the template’s edges over it, scoring each position by the mean distance from a template edge to the nearest scene edge (Chamfer matching). A perfect alignment costs ~0 regardless of how the shape is filled or shaded.

It reuses visual_match’s gray loaders / resize / NMS / Match and edge_lines’s Canny default, so no matching or geometry code is duplicated. The haystack is injectable (ndarray / path / PIL); the search is unit-testable on synthetic arrays. Imports no PySide6.

Headless API

from je_auto_control import edge_match, edge_match_all, chamfer_distance

# find a flat icon regardless of its fill colour / theme
hit = edge_match("chevron.png", min_score=0.7)
if hit:
    click(*hit.center)

for m in edge_match_all("divider_handle.png", min_score=0.8):
    print(m.center, m.score)

print(chamfer_distance("logo_outline.png"))   # 0 = edges coincide

edge_match returns the best Match (score = 1 / (1 + mean edge distance), so 1.0 is a perfect outline match) over the requested scales, or None. edge_match_all returns every match at or above min_score with overlaps removed by NMS. chamfer_distance returns the mean edge-to-edge distance at the best alignment (0 = the outlines coincide).

Executor commands

AC_edge_match (template / min_score / scales / region → {found, match}) and AC_edge_match_all (adds max_results / nms_iou → {count, matches}). They are exposed as the MCP tools ac_edge_match / ac_edge_match_all (read-only) and as the Script Builder commands Match Template (edge shape) / Match Template All (edge shape) under Image.