From 271d9824681127db5982b205341a77e2d9736e5c Mon Sep 17 00:00:00 2001
From: Lwen1243 <1198807618@qq.com>
Date: Tue, 23 Jun 2026 12:12:39 +0800
Subject: [PATCH 1/2] add yolov8 to coco

---
 .gitignore                      |   3 +-
 label_convert/yolov8_to_coco.py | 316 ++++++++++++++++++++++++++++++++
 tests/test_yolov8_to_coco.py    |  40 ++++
 3 files changed, 358 insertions(+), 1 deletion(-)
 create mode 100644 label_convert/yolov8_to_coco.py
 create mode 100644 tests/test_yolov8_to_coco.py

diff --git a/.gitignore b/.gitignore
index 6d3932f..88709c8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -168,4 +168,5 @@ long1.jpg
 *.pdiparams.info
 *.pdmodel
 
-.DS_Store
\ No newline at end of file
+.DS_Store
+test/
\ No newline at end of file
diff --git a/label_convert/yolov8_to_coco.py b/label_convert/yolov8_to_coco.py
new file mode 100644
index 0000000..5bff4e2
--- /dev/null
+++ b/label_convert/yolov8_to_coco.py
@@ -0,0 +1,316 @@
+# -*- encoding: utf-8 -*-
+# @Author: SWHL
+# @Contact: liekkaskono@163.com
+import argparse
+import json
+import shutil
+import time
+import warnings
+from pathlib import Path
+from typing import List, Tuple, Union
+
+import cv2
+import numpy as np
+from tqdm import tqdm
+
+ValueType = Union[str, Path, None]
+
+
+class YOLOv8ToCOCO:
+    def __init__(
+        self,
+        data_dir: ValueType = None,
+        save_dir: ValueType = None,
+        yaml_path: ValueType = None,
+    ):
+        if data_dir is None:
+            raise ValueError("data_dir must not be None")
+        self.data_dir = Path(data_dir)
+        self.verify_exists(self.data_dir)
+
+        self.img_dir = self.data_dir / "images"
+        self.verify_exists(self.img_dir)
+
+        self.label_dir = self.data_dir / "labels"
+        self.verify_exists(self.label_dir)
+
+        if save_dir is None:
+            save_dir = self.data_dir.parent / f"{Path(self.data_dir).name}_coco"
+        self.save_dir = save_dir
+        self.mkdir(self.save_dir)
+
+        self.yaml_path = yaml_path
+
+        self._init_json()
+
+    def __call__(self, mode_list: Tuple[str] = ("train", "val")):
+        if not mode_list:
+            raise ValueError("mode_list is empty!!")
+
+        for mode in mode_list:
+            mode_img_dir = self.img_dir / mode
+            self.verify_exists(mode_img_dir)
+            img_list = list(mode_img_dir.iterdir())
+
+            save_img_dir = self.save_dir / f"{mode}2017"
+            self.mkdir(save_img_dir)
+
+            anno_dir = self.save_dir / "annotations"
+            self.mkdir(anno_dir)
+
+            save_json_path = anno_dir / f"instances_{mode}2017.json"
+            json_data = self.convert(img_list, save_img_dir, mode)
+
+            self.write_json(save_json_path, json_data)
+        print(f"Successfully convert, detail in {self.save_dir}")
+
+    def _init_json(self):
+        if self.yaml_path is not None:
+            yaml_data = self.read_yaml(self.yaml_path)
+            class_names = list(yaml_data["names"].values())
+        else:
+            class_names = self._get_class_names_from_labels()
+
+        self.categories = self._get_category(class_names)
+
+        self.type = "instances"
+        self.annotation_id = 1
+
+        self.cur_year = time.strftime("%Y", time.localtime(time.time()))
+        self.info = {
+            "year": int(self.cur_year),
+            "version": "1.0",
+            "description": "For object detection",
+            "date_created": self.cur_year,
+        }
+
+        self.licenses = [
+            {
+                "id": 1,
+                "name": "Apache License v2.0",
+                "url": "https://github.com/RapidAI/LabelConvert/LICENSE",
+            }
+        ]
+
+    def _get_class_names_from_labels(self):
+        class_ids = set()
+        for mode in ("train", "val"):
+            mode_label_dir = self.label_dir / mode
+            if not mode_label_dir.exists():
+                continue
+            for label_path in mode_label_dir.iterdir():
+                if label_path.suffix != ".txt":
+                    continue
+                label_list = self.read_txt(str(label_path))
+                for line in label_list:
+                    if not line.strip():
+                        continue
+                    parts = line.strip().split()
+                    if parts:
+                        class_ids.add(int(parts[0]))
+
+        if not class_ids:
+            raise ValueError(
+                "No class ids found in labels. "
+                "Please provide a yaml_path with class names."
+            )
+
+        max_id = max(class_ids)
+        class_names = [""] * (max_id + 1)
+        for cid in class_ids:
+            class_names[cid] = f"class_{cid}"
+        return class_names
+
+    def _get_category(self, class_names):
+        categories = []
+        for i, name in enumerate(class_names):
+            if not name:
+                continue
+            categories.append(
+                {
+                    "supercategory": name,
+                    "id": i,
+                    "name": name,
+                }
+            )
+        return categories
+
+    def convert(self, img_list, save_img_dir, mode):
+        images, annotations = [], []
+        for img_id, img_path in enumerate(tqdm(img_list, desc=mode), 1):
+            image_dict = self.get_image_info(img_path, img_id, save_img_dir)
+            images.append(image_dict)
+
+            mode_label_dir = self.label_dir / mode
+            label_path = mode_label_dir / f"{img_path.stem}.txt"
+            if not label_path.exists():
+                warnings.warn(f"{label_path} not exists. Skip")
+                continue
+
+            annotation = self.read_annotation(
+                label_path, img_id, image_dict["height"], image_dict["width"]
+            )
+            annotations.extend(annotation)
+
+        json_data = {
+            "info": self.info,
+            "images": images,
+            "licenses": self.licenses,
+            "type": self.type,
+            "annotations": annotations,
+            "categories": self.categories,
+        }
+        return json_data
+
+    def get_image_info(self, img_path, img_id, save_img_dir):
+        img_path = Path(img_path)
+        self.verify_exists(img_path)
+
+        new_img_name = f"{img_id:012d}.jpg"
+        save_img_path = save_img_dir / new_img_name
+        img_src = cv2.imread(str(img_path))
+        if img_path.suffix.lower() == ".jpg":
+            shutil.copyfile(img_path, save_img_path)
+        else:
+            cv2.imwrite(str(save_img_path), img_src)
+
+        height, width = img_src.shape[:2]
+        image_info = {
+            "date_captured": self.cur_year,
+            "file_name": new_img_name,
+            "id": img_id,
+            "height": height,
+            "width": width,
+        }
+        return image_info
+
+    def read_annotation(self, label_path: Path, img_id, height, width):
+        annotation = []
+        label_list = self.read_txt(str(label_path))
+        for i, one_line in enumerate(label_list):
+            label_info = one_line.split(" ")
+            if len(label_info) < 5:
+                warnings.warn(f"The {i+1} line of the {label_path} has been corrupted.")
+                continue
+
+            category_id, vertex_info = label_info[0], label_info[1:]
+            point_nums = len(vertex_info)
+            if point_nums == 4:
+                segmentation, bbox, area = self.get_annotation_from_rectangle(
+                    vertex_info, height, width
+                )
+            elif point_nums > 4:
+                segmentation, bbox, area = self.get_annotation_from_poly(
+                    vertex_info, height, width
+                )
+            else:
+                warnings.warn("The nums of points are less than 4. Skip")
+                continue
+
+            annotation.append(
+                {
+                    "segmentation": segmentation,
+                    "area": area,
+                    "iscrowd": 0,
+                    "image_id": img_id,
+                    "bbox": bbox,
+                    "category_id": int(category_id) + 1,
+                    "id": self.annotation_id,
+                }
+            )
+            self.annotation_id += 1
+        return annotation
+
+    @staticmethod
+    def get_annotation_from_rectangle(vertex_info, height, width):
+        cx, cy, w, h = [float(i) for i in vertex_info]
+
+        cx = cx * width
+        cy = cy * height
+        box_w = w * width
+        box_h = h * height
+
+        x0 = max(cx - box_w / 2, 0)
+        y0 = max(cy - box_h / 2, 0)
+        x1 = min(x0 + box_w, width)
+        y1 = min(y0 + box_h, height)
+
+        segmentation = [[x0, y0, x1, y0, x1, y1, x0, y1]]
+        bbox = [x0, y0, box_w, box_h]
+        area = box_w * box_h
+        return segmentation, bbox, area
+
+    @staticmethod
+    def get_annotation_from_poly(vertex_info: List[str], height, width):
+        points = np.array(vertex_info).astype(np.float64).reshape(-1, 2)
+
+        new_points = np.copy(points)
+        new_points[:, 0] = points[:, 0] * width
+        new_points[:, 1] = points[:, 1] * height
+
+        segmentation = new_points.tolist()
+
+        x0, y0 = np.min(new_points, axis=0)
+        x1, y1 = np.max(new_points, axis=0)
+        box_w = x1 - x0
+        box_h = y1 - y0
+        bbox = [x0, y0, box_w, box_h]
+
+        area = box_w * box_h
+        return segmentation, bbox, area
+
+    @staticmethod
+    def read_txt(txt_path):
+        with open(str(txt_path), "r", encoding="utf-8") as f:
+            data = list(map(lambda x: x.rstrip("\n"), f))
+        return data
+
+    @staticmethod
+    def mkdir(dir_path):
+        Path(dir_path).mkdir(parents=True, exist_ok=True)
+
+    @staticmethod
+    def verify_exists(file_path: Union[Path, str]):
+        if not Path(file_path).exists():
+            raise FileNotFoundError(f"The {file_path} is not exists!!!")
+
+    @staticmethod
+    def write_json(json_path, content: dict):
+        with open(json_path, "w", encoding="utf-8") as f:
+            json.dump(content, f, ensure_ascii=False)
+
+    @staticmethod
+    def read_yaml(yaml_path):
+        import yaml
+
+        with open(yaml_path, "rb") as f:
+            data = yaml.load(f, Loader=yaml.Loader)
+        return data
+
+
+def main():
+    parser = argparse.ArgumentParser("Datasets converter from YOLOv8 to COCO")
+    parser.add_argument(
+        "--data_dir",
+        type=str,
+        default="tests/test_files/yolov8_dataset",
+        help="Dataset root path (contains images/ and labels/ subdirectories)",
+    )
+    parser.add_argument("--save_dir", type=str, default=None)
+    parser.add_argument(
+        "--mode_list", type=str, default="train,val", help="generate which mode"
+    )
+    parser.add_argument(
+        "--yaml_path",
+        type=str,
+        default=None,
+        help="YAML file path for class names (optional)",
+    )
+    args = parser.parse_args()
+
+    converter = YOLOv8ToCOCO(args.data_dir, args.save_dir, args.yaml_path)
+    converter(mode_list=args.mode_list.split(","))
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tests/test_yolov8_to_coco.py b/tests/test_yolov8_to_coco.py
new file mode 100644
index 0000000..8be29ff
--- /dev/null
+++ b/tests/test_yolov8_to_coco.py
@@ -0,0 +1,40 @@
+# -*- encoding: utf-8 -*-
+# @Author: SWHL
+# @Contact: liekkaskono@163.com
+import shutil
+import sys
+from pathlib import Path
+
+cur_dir = Path(__file__).resolve().parent
+root_dir = cur_dir.parent
+
+sys.path.append(str(root_dir))
+
+from label_convert.yolov8_to_coco import YOLOv8ToCOCO
+
+test_file_dir = cur_dir / "test_files"
+
+data_dir_name = "yolov8_dataset"
+
+
+def test_normal():
+    data_dir = test_file_dir / data_dir_name
+    converter = YOLOv8ToCOCO(data_dir)
+    converter()
+
+    save_dir: Path = test_file_dir / f"{data_dir_name}_coco"
+    assert save_dir.exists()
+
+    train_json_path = save_dir / "annotations" / "instances_train2017.json"
+    assert train_json_path.exists()
+
+    val_json_path = save_dir / "annotations" / "instances_val2017.json"
+    assert val_json_path.exists()
+
+    train_dir: Path = save_dir / "train2017"
+    assert train_dir.exists()
+
+    val_dir: Path = save_dir / "val2017"
+    assert val_dir.exists()
+
+    shutil.rmtree(save_dir)

From a968ec7247b2222f003d20f58a887dead1c4361e Mon Sep 17 00:00:00 2001
From: Lwen1243 <1198807618@qq.com>
Date: Tue, 23 Jun 2026 12:17:46 +0800
Subject: [PATCH 2/2] update author

---
 label_convert/yolov8_to_coco.py | 4 ++--
 tests/test_yolov8_to_coco.py    | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/label_convert/yolov8_to_coco.py b/label_convert/yolov8_to_coco.py
index 5bff4e2..f665a38 100644
--- a/label_convert/yolov8_to_coco.py
+++ b/label_convert/yolov8_to_coco.py
@@ -1,6 +1,6 @@
 # -*- encoding: utf-8 -*-
-# @Author: SWHL
-# @Contact: liekkaskono@163.com
+# @Author: Lwen1243
+# @Contact: 1198807618@qq.com
 import argparse
 import json
 import shutil
diff --git a/tests/test_yolov8_to_coco.py b/tests/test_yolov8_to_coco.py
index 8be29ff..f4dd3df 100644
--- a/tests/test_yolov8_to_coco.py
+++ b/tests/test_yolov8_to_coco.py
@@ -1,6 +1,6 @@
 # -*- encoding: utf-8 -*-
-# @Author: SWHL
-# @Contact: liekkaskono@163.com
+# @Author: Lwen1243
+# @Contact: 1198807618@qq.com
 import shutil
 import sys
 from pathlib import Path