VOC数据集格式转COCO数据集格式

    项目需要coco格式的数据集但是自己的数据集是VOC格式的该如何转换呢。

VOC格式

coco格式：

因为VOC格式的数据集中图片是放在一个文件下的，所以需要先划分训练集、验证集和测试集的比例，需要改两行文件路径和划分比例

import os
import random
import argparse

parser = argparse.ArgumentParser()
#xml文件的地址，根据自己的数据进行修改 xml一般存放在Annotations下
parser.add_argument('--xml_path', default='F:\dataset\VOCWSODD\Annotations', type=str, help='input xml label path')
#数据集的划分，地址选择自己数据下的ImageSets/Main
parser.add_argument('--txt_path', default='F:\dataset\VOCWSODD\ImageSets\Main', type=str, help='output txt label path')
opt = parser.parse_args()

trainval_percent = 0.8  # 训练+验证集一共所占的比例为0.8（注意看清楚），剩下的0.2就是测试集
train_percent = 0.8     # 训练集在训练集和验证集总集合中占的比例（注意看清楚是谁占谁的比例），可自己进行调整
xmlfilepath = opt.xml_path
txtsavepath = opt.txt_path
total_xml = os.listdir(xmlfilepath)
if not os.path.exists(txtsavepath):
    os.makedirs(txtsavepath)

num = len(total_xml)
list_index = range(num)
tv = int(num * trainval_percent)
tr = int(tv * train_percent)
trainval = random.sample(list_index, tv)
train = random.sample(trainval, tr)

file_trainval = open(txtsavepath + '/trainval.txt', 'w')
file_test = open(txtsavepath + '/test.txt', 'w')
file_train = open(txtsavepath + '/train.txt', 'w')
file_val = open(txtsavepath + '/val.txt', 'w')

for i in list_index:
    name = total_xml[i][:-4] + '\n'
    if i in trainval:
        file_trainval.write(name)
        if i in train:
            file_train.write(name)
        else:
            file_val.write(name)
    else:
        file_test.write(name)

file_trainval.close()
file_train.close()
file_val.close()
file_test.close()

然后 根据划分的三个TXT文件将VOC的xml转为COCO的JSON，需要改最开始自己数据集中的类别和最后三行文件路径

import sys
import os
import json
import xml.etree.ElementTree as ET

START_BOUNDING_BOX_ID = 0
PRE_DEFINE_CATEGORIES = {"ship": 0, "harbor": 1, "boat": 2, "bridge": 3,
                         "rock": 4, "ball": 5, "platform": 6, "tree": 7,
                         "grass": 8, "person": 9, "rubbish": 10, "animal": 11,
                         "buoy": 12, "mast": 13}  # 修改的地方，修改为自己的类别

# If necessary, pre-define category and its id
#  PRE_DEFINE_CATEGORIES = {"aeroplane": 1, "bicycle": 2, "bird": 3, "boat": 4,
#  "bottle":5, "bus": 6, "car": 7, "cat": 8, "chair": 9,
#  "cow": 10, "diningtable": 11, "dog": 12, "horse": 13,
#  "motorbike": 14, "person": 15, "pottedplant": 16,
#  "sheep": 17, "sofa": 18, "train": 19, "tvmonitor": 20}

def get(root, name):
    vars = root.findall(name)
    return vars

def get_and_check(root, name, length):
    vars = root.findall(name)
    if len(vars) == 0:
        raise NotImplementedError('Can not find %s in %s.' % (name, root.tag))
    if length > 0 and len(vars) != length:
        raise NotImplementedError('The size of %s is supposed to be %d, but is %d.' % (name, length, len(vars)))
    if length == 1:
        vars = vars[0]
    return vars

def get_filename_as_int(filename):
    try:
        filename = os.path.splitext(filename)[0]
        return filename
    except:
        raise NotImplementedError('Filename %s is supposed to be an integer.' % (filename))

# xml_list为xml文件存放的txt文件名    xml_dir为真实xml的存放路径    json_file为存放的json路径
def convert(xml_list, xml_dir, json_file):
    list_fp = open(xml_list, 'r')
    json_dict = {"images": [], "type": "instances", "annotations": [],
                 "categories": []}
    categories = PRE_DEFINE_CATEGORIES
    bnd_id = START_BOUNDING_BOX_ID
    for line in list_fp:
        line = line.strip()
        line = line + ".xml"
        print("Processing %s" % (line))
        xml_f = os.path.join(xml_dir, line)
        tree = ET.parse(xml_f)
        root = tree.getroot()
        path = get(root, 'path')
        if len(path) == 1:
            filename = os.path.basename(path[0].text)
        elif len(path) == 0:
            filename = get_and_check(root, 'filename', 1).text
        else:
            raise NotImplementedError('%d paths found in %s' % (len(path), line))
        ## The filename must be a number
        image_id = get_filename_as_int(filename)
        size = get_and_check(root, 'size', 1)
        width = int(get_and_check(size, 'width', 1).text)
        height = int(get_and_check(size, 'height', 1).text)
        image = {'file_name': filename, 'height': height, 'width': width,
                 'id': image_id}
        json_dict['images'].append(image)
        ## Cruuently we do not support segmentation
        #  segmented = get_and_check(root, 'segmented', 1).text
        #  assert segmented == '0'
        for obj in get(root, 'object'):
            category = get_and_check(obj, 'name', 1).text
            if category not in categories:
                new_id = len(categories)
                categories[category] = new_id
            category_id = categories[category]
            bndbox = get_and_check(obj, 'bndbox', 1)
            xmin = int(get_and_check(bndbox, 'xmin', 1).text) - 1
            ymin = int(get_and_check(bndbox, 'ymin', 1).text) - 1
            xmax = int(get_and_check(bndbox, 'xmax', 1).text)
            ymax = int(get_and_check(bndbox, 'ymax', 1).text)
            assert (xmax > xmin)
            assert (ymax > ymin)
            o_width = abs(xmax - xmin)
            o_height = abs(ymax - ymin)
            ann = {'area': o_width * o_height, 'iscrowd': 0, 'image_id':
                image_id, 'bbox': [xmin, ymin, o_width, o_height],
                   'category_id': category_id, 'id': bnd_id, 'ignore': 0,
                   'segmentation': []}
            json_dict['annotations'].append(ann)
            bnd_id = bnd_id + 1

    for cate, cid in categories.items():
        cat = {'supercategory': 'none', 'id': cid, 'name': cate}
        json_dict['categories'].append(cat)
    json_fp = open(json_file, 'w')
    json_str = json.dumps(json_dict)
    json_fp.write(json_str)
    json_fp.close()
    list_fp.close()

if __name__ == '__main__':
    # xml_list为xml文件存放的txt文件名    xml_dir为真实xml的存放路径    json_file为存放的json路径
    xml_list = 'F:\dataset\VOCWSODD\ImageSets\Main\\test.txt'
    xml_dir = 'F:\dataset\VOCWSODD\Annotations'
    json_dir = 'F:\dataset\cocoU\\test.json'  # 注意！！！这里test.json先要自己创建，不然                                                                          #程序回报权限不足
    convert(xml_list, xml_dir, json_dir)

最后对图片进行拷贝，训练集、验证集和测试集的图片添加到不同的目录下（和COCO数据集格式一致），只需要改前三行

import os
import shutil

images_file_path = 'F:\dataset\VOCWSODD\JPEGImages\\'  #VOC数据中图片所在文件夹
split_data_file_path = 'F:\dataset\VOCWSODD\ImageSets\Main\\' #前面三个.txt文件所在文件夹
new_images_file_path = 'F:\dataset\cocoU\\' #图片输出文件夹

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")

注意文件路径一定要配置对，如果遇到\t这类的需要再加一个\变为\t，否则路径会报错