Gate YOLO tile labels by visible ratio

backend/tests/test_sprint130_operator_yolo_tile_dataset.py

@@ -38,6 +38,7 @@ def test_operator_yolo_tile_dataset_export_script_contract() -> None:
     assert "tile_size" in script
     assert "stride" in script
     assert "negative_keep_ratio" in script
+    assert "min_label_visible_ratio" in script
     assert "positive_tile_count" in script
     assert "negative_tile_count" in script
     assert "skipped_negative_tile_count" in script
@@ -64,6 +65,7 @@ def test_operator_yolo_tile_dataset_export_help_does_not_require_gis_dependencie
     assert "--tile-size" in result.stdout
     assert "--stride" in result.stdout
     assert "--negative-keep-ratio" in result.stdout
+    assert "--min-label-visible-ratio" in result.stdout
     assert "--background-negative-repeat" in result.stdout
 
 
@@ -96,6 +98,28 @@ def test_negative_tile_keep_is_deterministic_and_ratio_bound() -> None:
     assert not any(none_kept)
 
 
+def test_labels_for_tile_can_drop_tiny_visible_box_fragments() -> None:
+    module = load_tile_exporter()
+    tile = module.TileWindow(row_off=0, col_off=0, height=100, width=100)
+    mostly_outside_box = module.PixelBox(min_col=90, min_row=10, max_col=190, max_row=90)
+
+    labels_without_gate = module.labels_for_tile(
+        tile,
+        [mostly_outside_box],
+        min_label_px=4,
+        min_visible_ratio=0.0,
+    )
+    labels_with_gate = module.labels_for_tile(
+        tile,
+        [mostly_outside_box],
+        min_label_px=4,
+        min_visible_ratio=0.25,
+    )
+
+    assert labels_without_gate == ["0 0.95000000 0.50000000 0.10000000 0.80000000"]
+    assert labels_with_gate == []
+
+
 def test_background_negative_repeat_only_applies_to_training_background_tiles() -> None:
     module = load_tile_exporter()