nx_integral.nx

nx_integral.nx -- integral image (summed-area table). R-FACE-0: the foundation of fast Haar-feature / Viola-Jones face detection. After an O(N) build, the sum of ANY axis-aligned rectangle is O(1) via four lookups -- which is what makes a sliding-window cascade tractable. SAT[y][x] (1-based, with a zero top row + left col) = sum of all pixels strictly above-left. Rectangle [x0..x1] x [y0..y1] inclusive = S = SAT[y1+1][x1+1] - SAT[y0][x1+1] - SAT[y1+1][x0] + SAT[y0][x0]. Pure i64. Operates on a 1-channel (grayscale) Image. genealogy_id: crow_1984_summed_area_table + viola_jones_2001 (record-hint) lineage_id: summed_area_table + o1_rectangle_sum nx_safety_envelope: intended_use: "Foundation for Haar features / face detection." verdict: NOT_YET_EVALUATED license_tier: ORIGINAL