Add tools/region_check.py for REGION_MAP visual verification

Forces one image per region key (A..P) on both yellow and green plates.
Filename embeds our guessed Korean region name so a human reviewer can
compare the rendered region tile.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tools/region_check.py

@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+"""REGION_MAP 시각 검증용 — region 16종 각 1장씩 합성 (yellow + green)."""
+
+import random
+import sys
+from pathlib import Path
+
+import cv2
+
+sys.path.insert(0, str(Path(__file__).parent.parent / "data_gen"))
+from generate_synthetic import LPGenerator, REGION_MAP, HANGUL_CHAR_MAP  # noqa: E402
+
+
+def gen_with_region(gen, plate_bg, num_src, char_src, region_src, rkey):
+    plate = cv2.resize(plate_bg, (336, 170))
+    num1 = gen._resize_dict(num_src, 44, 60)
+    num2 = gen._resize_dict(num_src, 64, 90)
+    region = gen._resize_dict(region_src, 88, 60)
+    char = gen._resize_dict(char_src, 64, 62)
+
+    d = [random.choice("0123456789") for _ in range(2)]
+    ch = random.choice(list(HANGUL_CHAR_MAP))
+    e = [random.choice("0123456789") for _ in range(4)]
+
+    row, col = 8, 76
+    plate[row:row+60, col:col+88] = region[rkey]; col += 88 + 8
+    for x in d:
+        plate[row:row+60, col:col+44] = num1[x]; col += 44
+
+    row, col = 72, 8
+    plate[row:row+62, col:col+64] = char[ch]; col += 64
+    for x in e:
+        plate[row:row+90, col:col+64] = num2[x]; col += 64
+    return plate
+
+
+def main():
+    random.seed(0)
+    asset_dir = Path("/workspace/kr_lp_pgnet/data_gen/Korean-license-plate-Generator")
+    out_root = Path("/workspace/train_data")
+
+    gen = LPGenerator(asset_dir)
+
+    for color, plate_bg, num_src, char_src, region_src in [
+        ("y", gen.plate_y, gen.num_y, gen.char_y, gen.region_y_imgs),
+        ("g", gen.plate_g, gen.num_g, gen.char_g, gen.region_g_imgs),
+    ]:
+        out = out_root / f"region_check_{color}"
+        out.mkdir(parents=True, exist_ok=True)
+        for k in sorted(region_src.keys()):
+            img = gen_with_region(gen, plate_bg, num_src, char_src, region_src, k)
+            label = REGION_MAP.get(k, "?")
+            name = f"{color}_{k}_OUR_GUESS={label}.jpg"
+            cv2.imwrite(str(out / name), img)
+        print(f"  {color}: {len(region_src)} 장 → {out}")
+
+
+if __name__ == "__main__":
+    main()