学习视频：目标检测实战教程01-使用labelimg标注目标检测数据集 | voc转COCO数据集_哔哩哔哩_bilibili
1.脚本文件
下面是脚本文件，该脚本文件可以把目录下的多个 VOC 格式的 xml 标注文件转换为一个 COCO 格式的 json 文件，需要修改的地方写在代码前面了
java
"""
需要修改的地方
1. category_set = ['dog'],此处填写数据集的类别名称
2. 代码末尾处voc格式的xml标注文件所在的目录
3. 代码末尾处对应生成的json文件存放路径
4. 51行处，生成coco标签文件格式后缀名要与自己图片文件类型对应（此处为jpg）
注：训练集与测试集中类别的顺序必须保持一致，因此最好事先确定category的顺序，书写在category_set中
"""
import xml.etree.ElementTree as ET
import os
import json
import collections
coco = dict()
coco['images'] = []
coco['type'] = 'instances'
coco['annotations'] = []
coco['categories'] = []
# category_set = dict()
image_set = set()
image_id = 1 # train:2018xxx; val:2019xxx; test:2020xxx
category_item_id = 1
annotation_id = 1
#类别
category_set = ['person','bird','cat','cow','dog','horse','sheep','aeroplane','bicycle',
'boat','bus','car','motorbike','train','bottle','chair','diningtable','pottedplant',
'sofa','tvmonitor']
def addCatItem(name):
'''
增加json格式中的categories部分
'''
global category_item_id
category_item = collections.OrderedDict()
category_item['supercategory'] = 'none'
category_item['id'] = category_item_id
category_item['name'] = name
coco['categories'].append(category_item)
category_item_id += 1
def addImgItem(file_name, size):
global image_id
if file_name is None:
raise Exception('Could not find filename tag in xml file.')
if size['width'] is None:
raise Exception('Could not find width tag in xml file.')
if size['height'] is None:
raise Exception('Could not find height tag in xml file.')
# image_item = dict() #按照一定的顺序，这里采用collections.OrderedDict()
image_item = collections.OrderedDict()
jpg_name = os.path.splitext(file_name)[0] + '.jpg'
image_item['file_name'] = jpg_name
image_item['width'] = size['width']
image_item['height'] = size['height']
image_item['id'] = image_id
coco['images'].append(image_item)
image_set.add(jpg_name)
image_id = image_id + 1
return image_id
def addAnnoItem(object_name, image_id, category_id, bbox):
global annotation_id
# annotation_item = dict()
annotation_item = collections.OrderedDict()
annotation_item['segmentation'] = []
seg = []
# bbox[] is x,y,w,h
# left_top
seg.append(bbox[0])
seg.append(bbox[1])
# left_bottom
seg.append(bbox[0])
seg.append(bbox[1] + bbox[3])
# right_bottom
seg.append(bbox[0] + bbox[2])
seg.append(bbox[1] + bbox[3])
# right_top
seg.append(bbox[0] + bbox[2])
seg.append(bbox[1])
annotation_item['segmentation'].append(seg)
annotation_item['area'] = bbox[2] * bbox[3]
annotation_item['iscrowd'] = 0
annotation_item['image_id'] = image_id
annotation_item['bbox'] = bbox
annotation_item['category_id'] = category_id
annotation_item['id'] = annotation_id
annotation_item['ignore'] = 0
annotation_id += 1
coco['annotations'].append(annotation_item)
def parseXmlFiles(xml_path):
xmllist = os.listdir(xml_path)
xmllist.sort()
for f in xmllist:
if not f.endswith('.xml'):
continue
bndbox = dict()
size = dict()
current_image_id = None
current_category_id = None
file_name = None
size['width'] = None
size['height'] = None
size['depth'] = None
xml_file = os.path.join(xml_path, f)
print(xml_file)
tree = ET.parse(xml_file)
root = tree.getroot() # 抓根结点元素
if root.tag != 'annotation': # 根节点标签
raise Exception('pascal voc xml root element should be annotation, rather than {}'.format(root.tag))
# elem is <folder>, <filename>, <size>, <object>
for elem in root:
current_parent = elem.tag
current_sub = None
object_name = None
# elem.tag, elem.attrib，elem.text
if elem.tag == 'folder':
continue
if elem.tag == 'filename':
file_name = elem.text
if file_name in category_set:
raise Exception('file_name duplicated')
# add img item only after parse <size> tag
elif current_image_id is None and file_name is not None and size['width'] is not None:
if file_name not in image_set:
current_image_id = addImgItem(file_name, size) # 图片信息
print('add image with {} and {}'.format(file_name, size))
else:
raise Exception('duplicated image: {}'.format(file_name))
# subelem is <width>, <height>, <depth>, <name>, <bndbox>
for subelem in elem:
bndbox['xmin'] = None
bndbox['xmax'] = None
bndbox['ymin'] = None
bndbox['ymax'] = None
current_sub = subelem.tag
if current_parent == 'object' and subelem.tag == 'name':
object_name = subelem.text
# if object_name not in category_set:
# current_category_id = addCatItem(object_name)
# else:
# current_category_id = category_set[object_name]
current_category_id = category_set.index(object_name) + 1 # index默认从0开始,但是json文件是从1开始，所以+1
elif current_parent == 'size':
if size[subelem.tag] is not None:
raise Exception('xml structure broken at size tag.')
size[subelem.tag] = int(subelem.text)
# option is <xmin>, <ymin>, <xmax>, <ymax>, when subelem is <bndbox>
for option in subelem:
if current_sub == 'bndbox':
if bndbox[option.tag] is not None:
raise Exception('xml structure corrupted at bndbox tag.')
bndbox[option.tag] = int(option.text)
# only after parse the <object> tag
if bndbox['xmin'] is not None:
if object_name is None:
raise Exception('xml structure broken at bndbox tag')
if current_image_id is None:
raise Exception('xml structure broken at bndbox tag')
if current_category_id is None:
raise Exception('xml structure broken at bndbox tag')
bbox = []
# x
bbox.append(bndbox['xmin'])
# y
bbox.append(bndbox['ymin'])
# w
bbox.append(bndbox['xmax'] - bndbox['xmin'])
# h
bbox.append(bndbox['ymax'] - bndbox['ymin'])
print(
'add annotation with {},{},{},{}'.format(object_name, current_image_id - 1, current_category_id,
bbox))
addAnnoItem(object_name, current_image_id - 1, current_category_id, bbox)
# categories部分
for categoryname in category_set:
addCatItem(categoryname)
if __name__ == '__main__':
xml_path = 'D:\BaiduNetdiskDownload\yolov8-ship\VOCdevkit\VOC2007\Annotations'#xml文件存放目录
json_file = 'D:\BaiduNetdiskDownload\yolov8-ship\coco.json'#生成的json文件存放路径
parseXmlFiles(xml_path)
json.dump(coco, open(json_file, 'w'))2.演示
VOC 格式的 xml 标注文件存放目录：D:\BaiduNetdiskDownload\yolov8-ship\okk
将脚本末尾处的 xml_path 修改为 ：D:\BaiduNetdiskDownload\yolov8-ship\okk，指定生成的 json文件存放路径为 D:\BaiduNetdiskDownload\yolov8-ship\okk\coco\train.json
执行脚本文件，生成 json 文件
