import json from collections import defaultdict from pathlib import Path import cv2 import numpy as np from tqdm import tqdm from ultralytics.yolo.utils.checks import check_requirements from ultralytics.yolo.utils.files import make_dirs def coco91_to_coco80_class(): """Converts 91-index COCO class IDs to 80-index COCO class IDs. Returns: (list): A list of 91 class IDs where the index represents the 80-index class ID and the value is the corresponding 91-index class ID. """ return [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, None, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, None, 24, 25, None, None, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, None, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, None, 60, None, None, 61, None, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, None, 73, 74, 75, 76, 77, 78, 79, None] def convert_coco(labels_dir='../coco/annotations/', use_segments=False, use_keypoints=False, cls91to80=True): """Converts COCO dataset annotations to a format suitable for training YOLOv5 models. Args: labels_dir (str, optional): Path to directory containing COCO dataset annotation files. use_segments (bool, optional): Whether to include segmentation masks in the output. use_keypoints (bool, optional): Whether to include keypoint annotations in the output. cls91to80 (bool, optional): Whether to map 91 COCO class IDs to the corresponding 80 COCO class IDs. Raises: FileNotFoundError: If the labels_dir path does not exist. Example Usage: convert_coco(labels_dir='../coco/annotations/', use_segments=True, use_keypoints=True, cls91to80=True) Output: Generates output files in the specified output directory. """ save_dir = make_dirs('yolo_labels') # output directory coco80 = coco91_to_coco80_class() # Import json for json_file in sorted(Path(labels_dir).resolve().glob('*.json')): fn = Path(save_dir) / 'labels' / json_file.stem.replace('instances_', '') # folder name fn.mkdir(parents=True, exist_ok=True) with open(json_file) as f: data = json.load(f) # Create image dict images = {'%g' % x['id']: x for x in data['images']} # Create image-annotations dict imgToAnns = defaultdict(list) for ann in data['annotations']: imgToAnns[ann['image_id']].append(ann) # Write labels file for img_id, anns in tqdm(imgToAnns.items(), desc=f'Annotations {json_file}'): img = images['%g' % img_id] h, w, f = img['height'], img['width'], img['file_name'] bboxes = [] segments = [] keypoints = [] for ann in anns: if ann['iscrowd']: continue # The COCO box format is [top left x, top left y, width, height] box = np.array(ann['bbox'], dtype=np.float64) box[:2] += box[2:] / 2 # xy top-left corner to center box[[0, 2]] /= w # normalize x box[[1, 3]] /= h # normalize y if box[2] <= 0 or box[3] <= 0: # if w <= 0 and h <= 0 continue cls = coco80[ann['category_id'] - 1] if cls91to80 else ann['category_id'] - 1 # class box = [cls] + box.tolist() if box not in bboxes: bboxes.append(box) if use_segments and ann.get('segmentation') is not None: if len(ann['segmentation']) == 0: segments.append([]) continue if isinstance(ann['segmentation'], dict): ann['segmentation'] = rle2polygon(ann['segmentation']) if len(ann['segmentation']) > 1: s = merge_multi_segment(ann['segmentation']) s = (np.concatenate(s, axis=0) / np.array([w, h])).reshape(-1).tolist() else: s = [j for i in ann['segmentation'] for j in i] # all segments concatenated s = (np.array(s).reshape(-1, 2) / np.array([w, h])).reshape(-1).tolist() s = [cls] + s if s not in segments: segments.append(s) if use_keypoints and ann.get('keypoints') is not None: k = (np.array(ann['keypoints']).reshape(-1, 3) / np.array([w, h, 1])).reshape(-1).tolist() k = box + k keypoints.append(k) # Write with open((fn / f).with_suffix('.txt'), 'a') as file: for i in range(len(bboxes)): if use_keypoints: line = *(keypoints[i]), # cls, box, keypoints else: line = *(segments[i] if use_segments and len(segments[i]) > 0 else bboxes[i]), # cls, box or segments file.write(('%g ' * len(line)).rstrip() % line + '\n') def rle2polygon(segmentation): """ Convert Run-Length Encoding (RLE) mask to polygon coordinates. Args: segmentation (dict, list): RLE mask representation of the object segmentation. Returns: (list): A list of lists representing the polygon coordinates for each contour. Note: Requires the 'pycocotools' package to be installed. """ check_requirements('pycocotools') from pycocotools import mask m = mask.decode(segmentation) m[m > 0] = 255 contours, _ = cv2.findContours(m, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_TC89_KCOS) polygons = [] for contour in contours: epsilon = 0.001 * cv2.arcLength(contour, True) contour_approx = cv2.approxPolyDP(contour, epsilon, True) polygon = contour_approx.flatten().tolist() polygons.append(polygon) return polygons def min_index(arr1, arr2): """ Find a pair of indexes with the shortest distance between two arrays of 2D points. Args: arr1 (np.array): A NumPy array of shape (N, 2) representing N 2D points. arr2 (np.array): A NumPy array of shape (M, 2) representing M 2D points. Returns: (tuple): A tuple containing the indexes of the points with the shortest distance in arr1 and arr2 respectively. """ dis = ((arr1[:, None, :] - arr2[None, :, :]) ** 2).sum(-1) return np.unravel_index(np.argmin(dis, axis=None), dis.shape) def merge_multi_segment(segments): """ Merge multiple segments into one list by connecting the coordinates with the minimum distance between each segment. This function connects these coordinates with a thin line to merge all segments into one. Args: segments (List[List]): Original segmentations in COCO's JSON file. Each element is a list of coordinates, like [segmentation1, segmentation2,...]. Returns: s (List[np.ndarray]): A list of connected segments represented as NumPy arrays. """ s = [] segments = [np.array(i).reshape(-1, 2) for i in segments] idx_list = [[] for _ in range(len(segments))] # record the indexes with min distance between each segment for i in range(1, len(segments)): idx1, idx2 = min_index(segments[i - 1], segments[i]) idx_list[i - 1].append(idx1) idx_list[i].append(idx2) # use two round to connect all the segments for k in range(2): # forward connection if k == 0: for i, idx in enumerate(idx_list): # middle segments have two indexes # reverse the index of middle segments if len(idx) == 2 and idx[0] > idx[1]: idx = idx[::-1] segments[i] = segments[i][::-1, :] segments[i] = np.roll(segments[i], -idx[0], axis=0) segments[i] = np.concatenate([segments[i], segments[i][:1]]) # deal with the first segment and the last one if i in [0, len(idx_list) - 1]: s.append(segments[i]) else: idx = [0, idx[1] - idx[0]] s.append(segments[i][idx[0]:idx[1] + 1]) else: for i in range(len(idx_list) - 1, -1, -1): if i not in [0, len(idx_list) - 1]: idx = idx_list[i] nidx = abs(idx[1] - idx[0]) s.append(segments[i][nidx:]) return s def delete_dsstore(path='../datasets'): """Delete Apple .DS_Store files in the specified directory and its subdirectories.""" from pathlib import Path files = list(Path(path).rglob('.DS_store')) print(files) for f in files: f.unlink() if __name__ == '__main__': source = 'COCO' if source == 'COCO': convert_coco( '../datasets/coco/annotations', # directory with *.json use_segments=False, use_keypoints=True, cls91to80=False)