1. 基础知识（了解VOC格式以及COCO格式的目录结构）
转换之前先将自己的数据集目录变成标准的VOC格式目录
首先看VOC格式的目录结构
再看一下COCO格式的目录结构
2. 新建labels.txt文件
文件内容替换为自己的数据集类别名
RBC
WBC
Platelets
3. json格式的标签文件转换程序
import os
import argparse
import json
import xml.etree.ElementTree as ET
from typing import Dict, List
import re
def get_label2id(labels_path: str) -> Dict[str, int]:
"""id is 1 start"""
with open(labels_path, 'r') as f:
labels_str = f.read().split()
labels_ids = list(range(1, len(labels_str)+1))
return dict(zip(labels_str, labels_ids))
def get_annpaths(ann_dir_path: str = None,
ann_ids_path: str = None,
ext: str = '',
annpaths_list_path: str = None) -> List[str]:
if annpaths_list_path is not None:
with open(annpaths_list_path, 'r') as f:
ann_paths = f.read().split()
return ann_paths
ext_with_dot = '.' + ext if ext != '' else ''
with open(ann_ids_path, 'r') as f:
ann_ids = f.read().split()
ann_paths = [os.path.join(ann_dir_path, aid+ext_with_dot) for aid in ann_ids]
return ann_paths
def get_image_info(annotation_root, extract_num_from_imgid=True):
path = annotation_root.findtext('path')
if path is None:
filename = annotation_root.findtext('filename')
else:
filename = os.path.basename(path)
img_name = os.path.basename(filename)
img_id = os.path.splitext(img_name)[0]
if extract_num_from_imgid and isinstance(img_id, str):
img_id = int(re.findall(r'\d+', img_id)[0])
size = annotation_root.find('size')
width = int(size.findtext('width'))
height = int(size.findtext('height'))
image_info = {
'file_name': filename,
'height': height,
'width': width,
'id': img_id
}
return image_info
def get_coco_annotation_from_obj(obj, label2id):
label = obj.findtext('name')
assert label in label2id, f"Error: {label} is not in label2id !"
category_id = label2id[label]
bndbox = obj.find('bndbox')
xmin = int(bndbox.findtext('xmin')) - 1
ymin = int(bndbox.findtext('ymin')) - 1
xmax = int(bndbox.findtext('xmax'))
ymax = int(bndbox.findtext('ymax'))
assert xmax > xmin and ymax > ymin, f"Box size error !: (xmin, ymin, xmax, ymax): {xmin, ymin, xmax, ymax}"
o_width = xmax - xmin
o_height = ymax - ymin
ann = {
'area': o_width * o_height,
'iscrowd': 0,
'bbox': [xmin, ymin, o_width, o_height],
'category_id': category_id,
'ignore': 0,
'segmentation': []
}
return ann
def convert_xmls_to_cocojson(annotation_paths: List[str],
label2id: Dict[str, int],
output_jsonpath: str,
extract_num_from_imgid: bool = True):
output_json_dict = {
"images": [],
"type": "instances",
"annotations": [],
"categories": []
}
bnd_id = 1
for a_path in annotation_paths:
ann_tree = ET.parse(a_path)
ann_root = ann_tree.getroot()
img_info = get_image_info(annotation_root=ann_root,
extract_num_from_imgid=extract_num_from_imgid)
img_id = img_info['id']
output_json_dict['images'].append(img_info)
for obj in ann_root.findall('object'):
ann = get_coco_annotation_from_obj(obj=obj, label2id=label2id)
ann.update({'image_id': img_id, 'id': bnd_id})
output_json_dict['annotations'].append(ann)
bnd_id = bnd_id + 1
for label, label_id in label2id.items():
category_info = {'supercategory': 'none', 'id': label_id, 'name': label}
output_json_dict['categories'].append(category_info)
with open(output_jsonpath, 'w') as f:
output_json = json.dumps(output_json_dict)
f.write(output_json)
print('Convert successfully !')
def main():
parser = argparse.ArgumentParser(
description='This script support converting voc format xmls to coco format json')
parser.add_argument('--ann_dir', type=str, default='./Annotations')
parser.add_argument('--ann_ids', type=str, default='./ImageSets/Main/test.txt')
parser.add_argument('--ann_paths_list', type=str, default=None)
parser.add_argument('--labels', type=str, default='./labels.txt')
parser.add_argument('--output', type=str, default='./output/annotations/test.json')
parser.add_argument('--ext', type=str, default='xml')
args = parser.parse_args()
label2id = get_label2id(labels_path=args.labels)
ann_paths = get_annpaths(
ann_dir_path=args.ann_dir,
ann_ids_path=args.ann_ids,
ext=args.ext,
annpaths_list_path=args.ann_paths_list
)
convert_xmls_to_cocojson(
annotation_paths=ann_paths,
label2id=label2id,
output_jsonpath=args.output,
extract_num_from_imgid=True
)
if __name__ == '__main__':
if not os.path.exists('./output/annotations'):
os.makedirs('./output/annotations')
main()
4. 拷贝图像文件
import os
import shutil
images_file_path = './JPEGImages/'
split_data_file_path = './ImageSets/Main/'
new_images_file_path = './output/'
if not os.path.exists(new_images_file_path + 'train'):
os.makedirs(new_images_file_path + 'train')
if not os.path.exists(new_images_file_path + 'val'):
os.makedirs(new_images_file_path + 'val')
if not os.path.exists(new_images_file_path + 'test'):
os.makedirs(new_images_file_path + 'test')
dst_train_Image = new_images_file_path + 'train/'
dst_val_Image = new_images_file_path + 'val/'
dst_test_Image = new_images_file_path + 'test/'
total_txt = os.listdir(split_data_file_path)
for i in total_txt:
name = i[:-4]
if name == 'train':
txt_file = open(split_data_file_path + i, 'r')
for line in txt_file:
line = line.strip('\n')
line = line.strip('\r')
srcImage = images_file_path + line + '.jpg'
dstImage = dst_train_Image + line + '.jpg'
shutil.copyfile(srcImage, dstImage)
txt_file.close()
elif name == 'val':
txt_file = open(split_data_file_path + i, 'r')
for line in txt_file:
line = line.strip('\n')
line = line.strip('\r')
srcImage = images_file_path + line + '.jpg'
dstImage = dst_val_Image + line + '.jpg'
shutil.copyfile(srcImage, dstImage)
txt_file.close()
elif name == 'test':
txt_file = open(split_data_file_path + i, 'r')
for line in txt_file:
line = line.strip('\n')
line = line.strip('\r')
srcImage = images_file_path + line + '.jpg'
dstImage = dst_test_Image + line + '.jpg'
shutil.copyfile(srcImage, dstImage)
txt_file.close()
else:
print("Error, Please check the file name of folder")
