audit YOLO geometry and overlapping validation rows

2026-08-09 19:36:15 +02:00
parent fc18e72c7f
commit 736e773fb8
13 changed files with 789 additions and 16 deletions
@@ -23,6 +23,15 @@ The checkpoint matrix used only the 36-image non-protected validation split:
 measured mAP50 `0.345426` and mAP50-95 `0.140719`. The `reviewedexp6`
 challenger measured `0.368177` and `0.155438` respectively.

+A later exact cross-tile reconstruction established that this 512 px corpus
+uses stride 256. Across the full corpus, 74,113 interior label rows represent
+34,082 unique reconstructed objects; 40,031 rows are overlap repetitions and
+one object can occur four times. No reconstructed object crosses the
+train/validation boundary, but the tile rows are not statistically independent.
+The matrix therefore remains useful only for relative non-protected candidate
+ranking. Its mAP values are not an independent object-level accuracy estimate
+or a basis for narrow confidence claims.
+
 At confidence `0.25` and match IoU `0.25`, the active model measured F1
 `0.633058`; the challenger measured `0.642599`. Both produced zero detections
 on the 18 pure-background validation tiles at this threshold. At confidence
@@ -129,3 +138,26 @@ rewrite candidates. Excluding the 36 complete tiles would also discard 17,167
 unflagged labels, so no automatic tile exclusion or label mutation was made.
 The checksum-bound highlighted sheet and summary are recorded in the AI review
 ledger.
+
+## Row-level geometry and overlap follow-up
+
+The complete 79,192-label corpus was additionally audited at label-row level.
+The immutable manifest identifies 6,657 unique rows with at least one geometric
+training-risk signal: 1,812 rows have a width or height below 4 pixels, 26 have
+aspect ratio at least 8 and 5,079 touch a tile edge. The categories were
+rendered separately. All 23 extreme-aspect tiles and all 198 small-dimension
+tiles were inspected, plus a 64-tile edge sample.
+
+The extreme-aspect group predominantly shows plausible elongated sheds and
+building components. Sixteen of its 26 rows are also below 4 pixels, allowing
+the resolution floor to address most ambiguous extremes without deleting valid
+long structures. The small-dimension sheets contain many visually marginal
+miniature targets. The next immutable experimental corpus should therefore use
+the exporter's normal minimum dimension of at least 4 pixels instead of this
+legacy corpus's 3-pixel override. This finding does not justify mutating the
+frozen corpus or retroactively changing its checkpoint.
+
+The edge sample shows expected clipped buildings under the 0.35 minimum-visible
+policy. Raising that value may reduce partial-target pressure, but it must be a
+separately versioned ablation because removing all 5,079 rows without checking
+the original visible fraction would be unsound.