fix(detect): 钳掉 Label Studio 导出坐标的浮点溢出

真实导出里出现 height=1.0000000000000002:Label Studio 按百分比存框,导出时 /100
留下浮点误差。ultralytics 读标签时对 >1 的坐标直接报错,所以这点溢出必须钳掉,
否则装配出的数据集根本训不起来。

只钳 1e-6 量级的溢出,真正越界的坐标仍然报错。顺带把坐标统一写成 6 位小数。

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
This commit is contained in:
Shaun Zhou
2026-09-17 16:44:42 +08:00
co-authored by Claude Opus 5
parent 998e6601d4
commit 59d4b8a9c4
2 changed files with 76 additions and 12 deletions
+34 -11
View File
@@ -60,6 +60,12 @@ logger = None
EMPTY = "(无框)"
#: 坐标的容忍量。Label Studio 按百分比存框,导出时 /100 会有浮点误差,
#: 实测出现过 height=1.0000000000000002。ultralytics 对 >1 的坐标直接报错,
#: 所以这点溢出必须钳掉;超出这个量级的才是真的坏标签。
COORDINATE_TOLERANCE = 1e-6
class Sample(NamedTuple):
"""一张图、它的标签文本,以及分层划分用的类别。"""
@@ -105,12 +111,18 @@ def read_export(path: Path) -> tuple[list[str], dict[str, str]]:
return classes, labels
def parse_boxes(text: str, stem: str, num_classes: int) -> list[int]:
"""校验一个标签文件,返回其中所有框的类别下标。
def parse_boxes(text: str, stem: str, num_classes: int) -> tuple[list[int], str, int]:
"""校验并规整一个标签文件。
坐标越界或类别越界都直接报错:这类问题在训练时不会崩,只会悄悄拉低指标。
Returns:
(类别下标列表, 规整后的标签文本, 被钳位的坐标个数)
字段数、类别下标、明显越界的坐标都直接报错:这类问题在训练时不会崩,
只会悄悄拉低指标。只有浮点误差量级的溢出才钳到 [0,1]。
"""
class_ids = []
lines = []
clamped = 0
for number, line in enumerate(text.splitlines(), start=1):
line = line.strip()
if not line:
@@ -125,18 +137,22 @@ def parse_boxes(text: str, stem: str, num_classes: int) -> list[int]:
raise ExportError(f"{stem}.txt 第 {number} 行无法解析:{line!r}") from exc
if not 0 <= class_id < num_classes:
raise ExportError(f"{stem}.txt 第 {number} 行的类别下标 {class_id} 超出 0~{num_classes - 1}")
if not all(0.0 <= v <= 1.0 for v in coordinates):
if not all(-COORDINATE_TOLERANCE <= v <= 1 + COORDINATE_TOLERANCE for v in coordinates):
raise ExportError(f"{stem}.txt 第 {number} 行的坐标不在 [0,1] 内:{coordinates}")
clamped += sum(not 0.0 <= v <= 1.0 for v in coordinates)
coordinates = [min(max(v, 0.0), 1.0) for v in coordinates]
class_ids.append(class_id)
return class_ids
lines.append(" ".join([str(class_id), *(f"{v:.6f}" for v in coordinates)]))
return class_ids, "".join(f"{line}\n" for line in lines), clamped
def collect(
classes: list[str], labels: dict[str, str], images_dir: Path
) -> tuple[list[Sample], list[str]]:
"""把标签与图片配对,返回 (样本列表, 多余的图片名)。"""
) -> tuple[list[Sample], list[str], int]:
"""把标签与图片配对,返回 (样本列表, 多余的图片名, 钳位的坐标个数)。"""
samples = []
missing = []
clamped = 0
for stem, text in labels.items():
candidates = [
images_dir / f"{stem}{suffix}" for suffix in (".png", *IMAGE_SUFFIXES)
@@ -145,10 +161,11 @@ def collect(
if image is None:
missing.append(stem)
continue
class_ids = parse_boxes(text, stem, len(classes))
class_ids, cleaned, clamped_here = parse_boxes(text, stem, len(classes))
clamped += clamped_here
# 分层用"框最多的那个类别":一张图可能有多个类别的框,人工复核后尤其常见
stratum = classes[Counter(class_ids).most_common(1)[0][0]] if class_ids else EMPTY
samples.append(Sample(image, text, stratum))
samples.append(Sample(image, cleaned, stratum))
if missing:
raise ExportError(
@@ -160,7 +177,7 @@ def collect(
p.stem for p in images_dir.iterdir()
if p.suffix.lower() in IMAGE_SUFFIXES and p.stem not in known
)
return samples, extra
return samples, extra, clamped
def split(samples: list[Sample], val_ratio: float, seed: int) -> dict[str, list[Sample]]:
@@ -205,12 +222,17 @@ def main() -> int:
try:
classes, labels = read_export(Path(args.export))
samples, extra = collect(classes, labels, Path(args.images))
samples, extra, clamped = collect(classes, labels, Path(args.images))
except (ExportError, FileNotFoundError) as exc:
logger.error("%s", exc)
return 1
logger.info("导出: %s(%d 个标签,%d 类)", args.export, len(labels), len(classes))
if clamped:
logger.info(
"%d 个坐标有浮点误差量级的溢出(Label Studio 按百分比存框,/100 会有误差),已钳到 [0,1];"
"不钳的话 ultralytics 读标签时会直接报错", clamped,
)
if extra:
logger.warning(
"%s 里有 %d 张图片没有对应的标签,不会进入数据集(例如 %s)",
@@ -274,6 +296,7 @@ def main() -> int:
"empty_labels": len(empty),
"dropped_empty": args.drop_empty,
"images_without_label": len(extra),
"clamped_coordinates": clamped,
"val_ratio": args.val_ratio,
"seed": args.seed,
"split_sizes": {k: len(v) for k, v in splits.items()},
+42 -1
View File
@@ -76,7 +76,10 @@ def test_builds_a_split_dataset(export, tmp_path):
images, labels = outputs(out, "images"), outputs(out, "labels")
assert set(images) == set(LABELS) == set(labels)
for stem, path in labels.items():
assert path.read_text(encoding="utf-8") == LABELS[stem]
# 内容等价,但坐标统一成 6 位小数
written = [line.split() for line in path.read_text(encoding="utf-8").splitlines()]
expected = [line.split() for line in LABELS[stem].splitlines()]
assert [[v[0], *(f"{float(x):.6f}" for x in v[1:])] for v in expected] == written
# 图与标签必须落在同一个 split,否则验证集会混进训练图
assert path.parent.name == images[stem].parent.name
@@ -227,3 +230,41 @@ def test_refuses_to_clobber_and_dry_run_writes_nothing(export, tmp_path):
assert run(export, out) == 0
assert run(export, out) != 0 # 已存在且非空
assert run(export, out, "--overwrite") == 0
def _repack(archive, tmp_path, replacements):
"""复制一份导出,替换其中几个标签文件。"""
broken = tmp_path / "repacked.zip"
with zipfile.ZipFile(archive) as source, zipfile.ZipFile(broken, "w") as target:
for item in source.namelist():
data = replacements.get(item, source.read(item))
target.writestr(item, data.encode("utf-8") if isinstance(data, str) else data)
return broken
def test_float_overshoot_is_clamped(export, tmp_path, capsys):
"""Label Studio 按百分比存框,/100 后会出现 1.0000000000000002。
回归:不钳位的话 ultralytics 读标签时会直接报"坐标未归一化"而拒绝训练。
"""
archive, images = export
overshoot = "1 0.49999999999999994 0.5000000000000001 0.9999999999999999 1.0000000000000002\n"
repacked = _repack(archive, tmp_path, {"labels/grease_0001.txt": overshoot})
out = tmp_path / "out"
assert run((repacked, images), out) == 0
assert "已钳到 [0,1]" in capsys.readouterr().out
written = outputs(out, "labels")["grease_0001"].read_text(encoding="utf-8").split()
assert written == ["1", "0.500000", "0.500000", "1.000000", "1.000000"]
assert all(0.0 <= float(v) <= 1.0 for v in written[1:])
# 四个值里只有 1.0000000000000002 真的越界,其余虽有浮点误差但仍在 [0,1] 内
assert json.loads((out / "summary.json").read_text(encoding="utf-8"))["clamped_coordinates"] == 1
def test_real_out_of_range_is_still_rejected(export, tmp_path, capsys):
"""只钳浮点误差量级;真正越界的坐标仍要报错。"""
archive, images = export
repacked = _repack(archive, tmp_path, {"labels/grease_0001.txt": "1 0.5 1.02 0.1 0.1\n"})
assert run((repacked, images), tmp_path / "out") != 0
assert "不在 [0,1]" in capsys.readouterr().out