1 labelimg标注VOC格式和yolo格式介绍
labelimg标注工具怎么安装和使用在我的博客中已经讲解了,有需要可以看看,博客。

1.1 voc格式
VOC格式文件保存在和图像名称一样的xml文件中,xml文件中的标注信息如下图所示:文中红色框中保存着标注图片的主要信息。第一个红色框中里面显示着图片的保存在哪个文件夹中,标签对应的图片名称,还有图片保存的绝对路径。第二个红色框中的信息为标签图片的大小尺寸和通道,正常都是3通道。第三个红色框中的信息为图中标注的对象的信息,分别为该目标对象的属于哪一类,可以看出该对象名称为boat,然后还有标注框的两个点,分别为框的起始点和终结点。第四个红色框中的信息和第三个框框一样,都是我们标注对象的信息,不过该对象为cat。

1.2 yolo数据格式介绍

        yolo数据格式,是把每个图片的标注信息保存在一个和图片名称一样的txt文件中。txt文件中的信息如下图所示:

0 0.47416020671834624 0.4523809523809524 0.5968992248062015 0.683982683982684
1 0.874031007751938 0.4069264069264069 0.1227390180878553 0.2727272727272727

每一行代表标注的一个目标,第一个数字代表着这个数的类别,第一类目标就是0,第二类目标就是1,以此类推。后面的四个数字是归一化后的的标注的中心点坐标和归一化标注框的长和宽。

2 voc格式数据和yolo格式数据相互转换

2.1 voc转yolo代码

import xml.etree.ElementTree as ET
import pickle
import os
from os import listdir, getcwd
from os.path import join
 
 
def convert(size, box):
    x_center = (box[0] + box[1]) / 2.0
    y_center = (box[2] + box[3]) / 2.0
    x = x_center / size[0]
    y = y_center / size[1]
    w = (box[1] - box[0]) / size[0]
    h = (box[3] - box[2]) / size[1]
    return (x, y, w, h)
 
 
def convert_annotation(xml_files_path, save_txt_files_path, classes):
    xml_files = os.listdir(xml_files_path)
    print(xml_files)
    for xml_name in xml_files:
        print(xml_name)
        xml_file = os.path.join(xml_files_path, xml_name)
        out_txt_path = os.path.join(save_txt_files_path, xml_name.split('.')[0] + '.txt')
        out_txt_f = open(out_txt_path, 'w')
        tree = ET.parse(xml_file)
        root = tree.getroot()
        size = root.find('size')
        w = int(size.find('width').text)
        h = int(size.find('height').text)
 
        for obj in root.iter('object'):
            difficult = obj.find('difficult').text
            cls = obj.find('name').text
            if cls not in classes or int(difficult) == 1:
                continue
            cls_id = classes.index(cls)
            xmlbox = obj.find('bndbox')
            b = (float(xmlbox.find('xmin').text), float(xmlbox.find('xmax').text), float(xmlbox.find('ymin').text),
                 float(xmlbox.find('ymax').text))
            # b=(xmin, xmax, ymin, ymax)
            print(w, h, b)
            bb = convert((w, h), b)
            out_txt_f.write(str(cls_id) + " " + " ".join([str(a) for a in bb]) + '\n')
 
 
if __name__ == "__main__":
    # 需要转换的类别,需要一一对应
    classes1 = ['boat', 'cat']
    # 2、voc格式的xml标签文件路径
    xml_files1 = r'C:\Users\86159\Desktop\VOC2007\Annotations'
    # 3、转化为yolo格式的txt标签文件存储路径
    save_txt_files1 = r'C:\Users\86159\Desktop\VOC2007\label'
 
    convert_annotation(xml_files1, save_txt_files1, classes1)


2.2 yolo转voc格式代码

from xml.dom.minidom import Document
import os
import cv2
 
 
# def makexml(txtPath, xmlPath, picPath):  # txt所在文件夹路径,xml文件保存路径,图片所在文件夹路径
def makexml(picPath, txtPath, xmlPath):  # txt所在文件夹路径,xml文件保存路径,图片所在文件夹路径
    """此函数用于将yolo格式txt标注文件转换为voc格式xml标注文件
    在自己的标注图片文件夹下建三个子文件夹,分别命名为picture、txt、xml
    """
    dic = {'0': "boat",  # 创建字典用来对类型进行转换
           '1': "cat",  # 此处的字典要与自己的classes.txt文件中的类对应,且顺序要一致
           }
    files = os.listdir(txtPath)
    for i, name in enumerate(files):
        xmlBuilder = Document()
        annotation = xmlBuilder.createElement("annotation")  # 创建annotation标签
        xmlBuilder.appendChild(annotation)
        txtFile = open(txtPath + name)
        txtList = txtFile.readlines()
        img = cv2.imread(picPath + name[0:-4] + ".jpg")
        Pheight, Pwidth, Pdepth = img.shape
 
        folder = xmlBuilder.createElement("folder")  # folder标签
        foldercontent = xmlBuilder.createTextNode("driving_annotation_dataset")
        folder.appendChild(foldercontent)
        annotation.appendChild(folder)  # folder标签结束
 
        filename = xmlBuilder.createElement("filename")  # filename标签
        filenamecontent = xmlBuilder.createTextNode(name[0:-4] + ".jpg")
        filename.appendChild(filenamecontent)
        annotation.appendChild(filename)  # filename标签结束
 
        size = xmlBuilder.createElement("size")  # size标签
        width = xmlBuilder.createElement("width")  # size子标签width
        widthcontent = xmlBuilder.createTextNode(str(Pwidth))
        width.appendChild(widthcontent)
        size.appendChild(width)  # size子标签width结束
 
        height = xmlBuilder.createElement("height")  # size子标签height
        heightcontent = xmlBuilder.createTextNode(str(Pheight))
        height.appendChild(heightcontent)
        size.appendChild(height)  # size子标签height结束
 
        depth = xmlBuilder.createElement("depth")  # size子标签depth
        depthcontent = xmlBuilder.createTextNode(str(Pdepth))
        depth.appendChild(depthcontent)
        size.appendChild(depth)  # size子标签depth结束
 
        annotation.appendChild(size)  # size标签结束
 
        for j in txtList:
            oneline = j.strip().split(" ")
            object = xmlBuilder.createElement("object")  # object 标签
            picname = xmlBuilder.createElement("name")  # name标签
            namecontent = xmlBuilder.createTextNode(dic[oneline[0]])
            picname.appendChild(namecontent)
            object.appendChild(picname)  # name标签结束
 
            pose = xmlBuilder.createElement("pose")  # pose标签
            posecontent = xmlBuilder.createTextNode("Unspecified")
            pose.appendChild(posecontent)
            object.appendChild(pose)  # pose标签结束
 
            truncated = xmlBuilder.createElement("truncated")  # truncated标签
            truncatedContent = xmlBuilder.createTextNode("0")
            truncated.appendChild(truncatedContent)
            object.appendChild(truncated)  # truncated标签结束
 
            difficult = xmlBuilder.createElement("difficult")  # difficult标签
            difficultcontent = xmlBuilder.createTextNode("0")
            difficult.appendChild(difficultcontent)
            object.appendChild(difficult)  # difficult标签结束
 
            bndbox = xmlBuilder.createElement("bndbox")  # bndbox标签
            xmin = xmlBuilder.createElement("xmin")  # xmin标签
            mathData = int(((float(oneline[1])) * Pwidth + 1) - (float(oneline[3])) * 0.5 * Pwidth)
            xminContent = xmlBuilder.createTextNode(str(mathData))
            xmin.appendChild(xminContent)
            bndbox.appendChild(xmin)  # xmin标签结束
 
            ymin = xmlBuilder.createElement("ymin")  # ymin标签
            mathData = int(((float(oneline[2])) * Pheight + 1) - (float(oneline[4])) * 0.5 * Pheight)
            yminContent = xmlBuilder.createTextNode(str(mathData))
            ymin.appendChild(yminContent)
            bndbox.appendChild(ymin)  # ymin标签结束
 
            xmax = xmlBuilder.createElement("xmax")  # xmax标签
            mathData = int(((float(oneline[1])) * Pwidth + 1) + (float(oneline[3])) * 0.5 * Pwidth)
            xmaxContent = xmlBuilder.createTextNode(str(mathData))
            xmax.appendChild(xmaxContent)
            bndbox.appendChild(xmax)  # xmax标签结束
 
            ymax = xmlBuilder.createElement("ymax")  # ymax标签
            mathData = int(((float(oneline[2])) * Pheight + 1) + (float(oneline[4])) * 0.5 * Pheight)
            ymaxContent = xmlBuilder.createTextNode(str(mathData))
            ymax.appendChild(ymaxContent)
            bndbox.appendChild(ymax)  # ymax标签结束
 
            object.appendChild(bndbox)  # bndbox标签结束
 
            annotation.appendChild(object)  # object标签结束
 
        f = open(xmlPath + name[0:-4] + ".xml", 'w')
        xmlBuilder.writexml(f, indent='\t', newl='\n', addindent='\t', encoding='utf-8')
        f.close()
 
if __name__ == "__main__":
    picPath = "C:/Users/86159/Desktop/VOC2007/JPEGImage/"  # 图片所在文件夹路径,后面的/一定要带上
    txtPath = "C:/Users/86159/Desktop/VOC2007/yolo/"  # txt所在文件夹路径,后面的/一定要带上
    xmlPath = "C:/Users/86159/Desktop/VOC2007/Annotations1/"  # xml文件保存路径,后面的/一定要带上
    makexml(picPath, txtPath, xmlPath)