2025-03-26 11:26:55 +08:00

326 lines
12 KiB
Python

# Ultralytics 🚀 AGPL-3.0 License - https://ultralytics.com/license
import itertools
from glob import glob
from math import ceil
from pathlib import Path
import cv2
import numpy as np
from PIL import Image
from ultralytics.data.utils import exif_size, img2label_paths
from ultralytics.utils import TQDM
from ultralytics.utils.checks import check_requirements
def bbox_iof(polygon1, bbox2, eps=1e-6):
"""
Calculate Intersection over Foreground (IoF) between polygons and bounding boxes.
Args:
polygon1 (np.ndarray): Polygon coordinates with shape (n, 8).
bbox2 (np.ndarray): Bounding boxes with shape (n, 4).
eps (float, optional): Small value to prevent division by zero.
Returns:
(np.ndarray): IoF scores with shape (n, 1) or (n, m) if bbox2 is (m, 4).
Notes:
Polygon format: [x1, y1, x2, y2, x3, y3, x4, y4].
Bounding box format: [x_min, y_min, x_max, y_max].
"""
check_requirements("shapely")
from shapely.geometry import Polygon
polygon1 = polygon1.reshape(-1, 4, 2)
lt_point = np.min(polygon1, axis=-2) # left-top
rb_point = np.max(polygon1, axis=-2) # right-bottom
bbox1 = np.concatenate([lt_point, rb_point], axis=-1)
lt = np.maximum(bbox1[:, None, :2], bbox2[..., :2])
rb = np.minimum(bbox1[:, None, 2:], bbox2[..., 2:])
wh = np.clip(rb - lt, 0, np.inf)
h_overlaps = wh[..., 0] * wh[..., 1]
left, top, right, bottom = (bbox2[..., i] for i in range(4))
polygon2 = np.stack([left, top, right, top, right, bottom, left, bottom], axis=-1).reshape(-1, 4, 2)
sg_polys1 = [Polygon(p) for p in polygon1]
sg_polys2 = [Polygon(p) for p in polygon2]
overlaps = np.zeros(h_overlaps.shape)
for p in zip(*np.nonzero(h_overlaps)):
overlaps[p] = sg_polys1[p[0]].intersection(sg_polys2[p[-1]]).area
unions = np.array([p.area for p in sg_polys1], dtype=np.float32)
unions = unions[..., None]
unions = np.clip(unions, eps, np.inf)
outputs = overlaps / unions
if outputs.ndim == 1:
outputs = outputs[..., None]
return outputs
def load_yolo_dota(data_root, split="train"):
"""
Load DOTA dataset.
Args:
data_root (str): Data root directory.
split (str): The split data set, could be `train` or `val`.
Returns:
(List[Dict]): List of annotation dictionaries containing image information.
Notes:
The directory structure assumed for the DOTA dataset:
- data_root
- images
- train
- val
- labels
- train
- val
"""
assert split in {"train", "val"}, f"Split must be 'train' or 'val', not {split}."
im_dir = Path(data_root) / "images" / split
assert im_dir.exists(), f"Can't find {im_dir}, please check your data root."
im_files = glob(str(Path(data_root) / "images" / split / "*"))
lb_files = img2label_paths(im_files)
annos = []
for im_file, lb_file in zip(im_files, lb_files):
w, h = exif_size(Image.open(im_file))
with open(lb_file, encoding="utf-8") as f:
lb = [x.split() for x in f.read().strip().splitlines() if len(x)]
lb = np.array(lb, dtype=np.float32)
annos.append(dict(ori_size=(h, w), label=lb, filepath=im_file))
return annos
def get_windows(im_size, crop_sizes=(1024,), gaps=(200,), im_rate_thr=0.6, eps=0.01):
"""
Get the coordinates of windows.
Args:
im_size (tuple): Original image size, (h, w).
crop_sizes (List[int]): Crop size of windows.
gaps (List[int]): Gap between crops.
im_rate_thr (float): Threshold of windows areas divided by image areas.
eps (float): Epsilon value for math operations.
Returns:
(np.ndarray): Array of window coordinates with shape (n, 4) where each row is [x_start, y_start, x_stop, y_stop].
"""
h, w = im_size
windows = []
for crop_size, gap in zip(crop_sizes, gaps):
assert crop_size > gap, f"invalid crop_size gap pair [{crop_size} {gap}]"
step = crop_size - gap
xn = 1 if w <= crop_size else ceil((w - crop_size) / step + 1)
xs = [step * i for i in range(xn)]
if len(xs) > 1 and xs[-1] + crop_size > w:
xs[-1] = w - crop_size
yn = 1 if h <= crop_size else ceil((h - crop_size) / step + 1)
ys = [step * i for i in range(yn)]
if len(ys) > 1 and ys[-1] + crop_size > h:
ys[-1] = h - crop_size
start = np.array(list(itertools.product(xs, ys)), dtype=np.int64)
stop = start + crop_size
windows.append(np.concatenate([start, stop], axis=1))
windows = np.concatenate(windows, axis=0)
im_in_wins = windows.copy()
im_in_wins[:, 0::2] = np.clip(im_in_wins[:, 0::2], 0, w)
im_in_wins[:, 1::2] = np.clip(im_in_wins[:, 1::2], 0, h)
im_areas = (im_in_wins[:, 2] - im_in_wins[:, 0]) * (im_in_wins[:, 3] - im_in_wins[:, 1])
win_areas = (windows[:, 2] - windows[:, 0]) * (windows[:, 3] - windows[:, 1])
im_rates = im_areas / win_areas
if not (im_rates > im_rate_thr).any():
max_rate = im_rates.max()
im_rates[abs(im_rates - max_rate) < eps] = 1
return windows[im_rates > im_rate_thr]
def get_window_obj(anno, windows, iof_thr=0.7):
"""Get objects for each window."""
h, w = anno["ori_size"]
label = anno["label"]
if len(label):
label[:, 1::2] *= w
label[:, 2::2] *= h
iofs = bbox_iof(label[:, 1:], windows)
# Unnormalized and misaligned coordinates
return [(label[iofs[:, i] >= iof_thr]) for i in range(len(windows))] # window_anns
else:
return [np.zeros((0, 9), dtype=np.float32) for _ in range(len(windows))] # window_anns
def crop_and_save(anno, windows, window_objs, im_dir, lb_dir, allow_background_images=True):
"""
Crop images and save new labels.
Args:
anno (Dict): Annotation dict, including `filepath`, `label`, `ori_size` as its keys.
windows (np.ndarray): Array of windows coordinates with shape (n, 4).
window_objs (List): A list of labels inside each window.
im_dir (str): The output directory path of images.
lb_dir (str): The output directory path of labels.
allow_background_images (bool): Whether to include background images without labels.
Notes:
The directory structure assumed for the DOTA dataset:
- data_root
- images
- train
- val
- labels
- train
- val
"""
im = cv2.imread(anno["filepath"])
name = Path(anno["filepath"]).stem
for i, window in enumerate(windows):
x_start, y_start, x_stop, y_stop = window.tolist()
new_name = f"{name}__{x_stop - x_start}__{x_start}___{y_start}"
patch_im = im[y_start:y_stop, x_start:x_stop]
ph, pw = patch_im.shape[:2]
label = window_objs[i]
if len(label) or allow_background_images:
cv2.imwrite(str(Path(im_dir) / f"{new_name}.jpg"), patch_im)
if len(label):
label[:, 1::2] -= x_start
label[:, 2::2] -= y_start
label[:, 1::2] /= pw
label[:, 2::2] /= ph
with open(Path(lb_dir) / f"{new_name}.txt", "w", encoding="utf-8") as f:
for lb in label:
formatted_coords = [f"{coord:.6g}" for coord in lb[1:]]
f.write(f"{int(lb[0])} {' '.join(formatted_coords)}\n")
def split_images_and_labels(data_root, save_dir, split="train", crop_sizes=(1024,), gaps=(200,)):
"""
Split both images and labels.
Args:
data_root (str): Root directory of the dataset.
save_dir (str): Directory to save the split dataset.
split (str): The split data set, could be `train` or `val`.
crop_sizes (tuple): Tuple of crop sizes.
gaps (tuple): Tuple of gaps between crops.
Notes:
The directory structure assumed for the DOTA dataset:
- data_root
- images
- split
- labels
- split
and the output directory structure is:
- save_dir
- images
- split
- labels
- split
"""
im_dir = Path(save_dir) / "images" / split
im_dir.mkdir(parents=True, exist_ok=True)
lb_dir = Path(save_dir) / "labels" / split
lb_dir.mkdir(parents=True, exist_ok=True)
annos = load_yolo_dota(data_root, split=split)
for anno in TQDM(annos, total=len(annos), desc=split):
windows = get_windows(anno["ori_size"], crop_sizes, gaps)
window_objs = get_window_obj(anno, windows)
crop_and_save(anno, windows, window_objs, str(im_dir), str(lb_dir))
def split_trainval(data_root, save_dir, crop_size=1024, gap=200, rates=(1.0,)):
"""
Split train and val set of DOTA.
Args:
data_root (str): Root directory of the dataset.
save_dir (str): Directory to save the split dataset.
crop_size (int): Base crop size.
gap (int): Base gap between crops.
rates (tuple): Scaling rates for crop_size and gap.
Notes:
The directory structure assumed for the DOTA dataset:
- data_root
- images
- train
- val
- labels
- train
- val
and the output directory structure is:
- save_dir
- images
- train
- val
- labels
- train
- val
"""
crop_sizes, gaps = [], []
for r in rates:
crop_sizes.append(int(crop_size / r))
gaps.append(int(gap / r))
for split in ["train", "val"]:
split_images_and_labels(data_root, save_dir, split, crop_sizes, gaps)
def split_test(data_root, save_dir, crop_size=1024, gap=200, rates=(1.0,)):
"""
Split test set of DOTA, labels are not included within this set.
Args:
data_root (str): Root directory of the dataset.
save_dir (str): Directory to save the split dataset.
crop_size (int): Base crop size.
gap (int): Base gap between crops.
rates (tuple): Scaling rates for crop_size and gap.
Notes:
The directory structure assumed for the DOTA dataset:
- data_root
- images
- test
and the output directory structure is:
- save_dir
- images
- test
"""
crop_sizes, gaps = [], []
for r in rates:
crop_sizes.append(int(crop_size / r))
gaps.append(int(gap / r))
save_dir = Path(save_dir) / "images" / "test"
save_dir.mkdir(parents=True, exist_ok=True)
im_dir = Path(data_root) / "images" / "test"
assert im_dir.exists(), f"Can't find {im_dir}, please check your data root."
im_files = glob(str(im_dir / "*"))
for im_file in TQDM(im_files, total=len(im_files), desc="test"):
w, h = exif_size(Image.open(im_file))
windows = get_windows((h, w), crop_sizes=crop_sizes, gaps=gaps)
im = cv2.imread(im_file)
name = Path(im_file).stem
for window in windows:
x_start, y_start, x_stop, y_stop = window.tolist()
new_name = f"{name}__{x_stop - x_start}__{x_start}___{y_start}"
patch_im = im[y_start:y_stop, x_start:x_stop]
cv2.imwrite(str(save_dir / f"{new_name}.jpg"), patch_im)
if __name__ == "__main__":
split_trainval(data_root="DOTAv2", save_dir="DOTAv2-split")
split_test(data_root="DOTAv2", save_dir="DOTAv2-split")