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

Posted 2022-12-23 为成大道踏平坎坷

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

b站视频演示：B站视频教学

对图像进行编号

将收集到的图像进行编号方便统一管理，编号代码如下

import os
path = "E:\\\\image1"
filelist = os.listdir(path) #该文件夹下所有的文件（包括文件夹）
count=0
for file in filelist:
    print(file)
for file in filelist:   #遍历所有文件
    Olddir=os.path.join(path,file)   #原来的文件路径
    if os.path.isdir(Olddir):   #如果是文件夹则跳过
        continue
    filename=os.path.splitext(file)[0]   #文件名
    filetype=os.path.splitext(file)[1]   #文件扩展名
    Newdir=os.path.join(path,str(count).zfill(6)+filetype)  #用字符串函数zfill 以0补全所需位数
    os.rename(Olddir,Newdir)#重命名
    count+=1

安装labelimg图像标注软件

在cmd命令框输入

pip install labelimg -i https://pypi.tuna.tsinghua.edu.cn/simple

labelimg使用方法

基础功能如下表：

open	打开单张图片
opendir	打开图像文件夹
change save dir	修改标注保存文件夹
save	保存标注文件
a键	上一张图片
d键	下一张图片
w键	绘制矩形框

更多使用技巧（自动保存、连续标注、单一类别）讲解，请观看视频学习。

划分数据集

将已经标注好的标注文件按照比例划分为训练集与测试集，分别放在两个文件夹中，方便下一步的转化。

VOC转COCO

因为COCO数据集在算法训练的时候可以调用coco api，所以评价指标相比voc的map50指标种类过多，如果做研究的话，coco评价指标可以自动获取不同IoU阈值下的mAP值，并且支持对大中小三种尺寸目标物的评估指标，所以我通常会将标注好的VOC格式的数据集转化为COCO格式。

代码如下：

"""
需要修改的地方
1. category_set = ['TBC']此处的类别信息需要修改
2. 代码末尾处的voc标注文件夹
3. 带末尾处对应生成的json文件名
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
category_set = ['TBC']

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] + '.bmp'
    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 = 'C:/Users/wangchen/Desktop/12345/big/Annotations'
    json_file = 'C:/Users/wangchen/Desktop/12345/big/coco.json'
    parseXmlFiles(xml_path)
json.dump(coco, open(json_file, 'w'))