替换 VOC 数据集中图片路径

HauHau

发布于 2022-01-12 09:07:28

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发布于 2022-01-12 09:07:28

文章被收录于专栏：叹世界叹世界

前言

在一次做项目的时候，团队分配任务做数据集，用 labelimage 来打标，汇总数据时发现 xml 中的图片路径各不相同，于是就写了这个工具来修改 xml 中的图片路径。

原理

先打开一个 xml 文件，观察一下它的结构

<annotation>
    <folder>zhua_qu</folder>
    <filename>2021_03_16_16_42_11_296.jpg</filename>
    <path>D:\xyolo\images\train\2021_03_16_16_42_11_296.jpg</path>
    <source>
        <database>Unknown</database>
    </source>
    <size>
        <width>640</width>
        <height>480</height>
        <depth>3</depth>
    </size>
    <segmented>0</segmented>
    <object>
        <name>zhua_qu</name>
        <pose>Unspecified</pose>
        <truncated>0</truncated>
        <difficult>0</difficult>
        <bndbox>
            <xmin>389</xmin>
            <ymin>225</ymin>
            <xmax>522</xmax>
            <ymax>359</ymax>
        </bndbox>
    </object>
</annotation>

可以发现图片文件名在 <filename> 和 </filename > 标签之间，图片路径在 < path > 和 </path > 标签之间，理论上来说我们只要将 < path > 和 </path > 之间的图片路径替换成我们想要的就可以了

这个路径我们怎么生成，将要替换成的路径加上文件名就可以了，在这里我们不用考虑 c++ 烦人的中文乱码问题，就算我们要替换成中文路径，但是我们不考虑读取这些路径，直接替换 xml 中的图片路径即可。

到这里，替换的问题已经有思路了，然后我们再考虑批处理的问题，这里我用了 <io.h> 这个库来对指定的目录进行遍历，如果遇到目录就用递归的方法继续遍历，对检测到的文件进行过滤，留下 xml 文件的路径，压入一个 vector 容器中，后面 pop 出来调用替换的函数或者类来处理。

代码

main.cpp

#include <iostream>
#include <vector>
#include <string>
#include <chrono>
#include "replace.h"
#include "getfiles.h"


void help(const char* name)
{
    std::string progname = name;
    size_t lastPos = progname.find_last_of("/\\");
    progname = progname.substr(lastPos + 1);

    // 显示帮助
    std::cout << std::endl;
    std::cout << "This tool replaces the file path of the image in the XML file in the dataset" << std::endl << std::endl;
    std::cout << "Usage: " << std::endl;
    std::cout <<  "\t.\\" << progname << " [DataSet Path] [Replace Path]" << std::endl << std::endl;
    std::cout << "For example: " << std::endl;
    std::cout << "\t.\\main.exe C:\\Users\\17740\\Desktop\\DataSet\\ D:\\xyolo\\images\\train\\" 
    << std::endl << std::endl;
}


int main(int argc, char **argv)
{
    // 显示帮助
    if(argc == 1 || (argc == 2 &&(strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-h") == 0)))
    {
        help(argv[0]);
        return 0;
    }

    // 开始计时
    auto start = std::chrono::system_clock::now();

    std::string filePath = argv[1];
    std::string replace = argv[2];
    std::vector<std::string> files;

    // 规范化字符串
    if(filePath.find_last_of("\\") == filePath.length() - 1)
    {
        filePath.pop_back();
    }
    
    // 获取目录中的全部xml文件的路径
    getFiles(filePath, files);
    
    std::cout << "Replace...";

    int size = files.size();
    for (int i = 0; i < size; i++)
    {
        //std::cout << files[i].c_str() << std::endl;
        Replace r(replace, files[i]);
        r.work();
    }
    
    std::cout << "\rDone...   " << std::endl << std::endl;

    // 结束计时
    std::chrono::duration<double> diff = std::chrono::system_clock::now() - start;
    std::cout << "\tUsed: " << diff.count() << " Second" << std::endl;
    
    return 0;
}

replace.h

#include <iostream>
#include <fstream>
#include <string>


class Replace
{
private:
    std::string str;
    std::fstream f;
    char buf[1024];

private:
    std::string replace;
    std::string xmlname;
    std::string filename;
    std::string filename_label_start;
    std::string filename_label_end;
    std::string path_label_start;
    std::string path_label__end;
    int filename_pos_start;
    int filename_pos_end;
    int filenameLength;
    int path_pos_start;
    int path_pos__end;
    int pathLength;

public:
    bool work();

public:
    Replace(const std::string& replace, const std::string& xmlname);

};

replace.cpp

#include "replace.h"


Replace::Replace(const std::string& replace, const std::string& xmlname)
{
    this->replace = replace;
    this->xmlname = xmlname;
    filename_label_start    = "<filename>";
    filename_label_end      = "</filename>";
    path_label_start        = "<path>";
    path_label__end         = "</path>";
    filename_pos_start  = 0;
    filename_pos_end    = 0;
    filenameLength      = 0;
    path_pos_start      = 0;
    path_pos__end       = 0;
    pathLength          = 0;

    if(this->replace.find_last_of("\\") < this->replace.length() - 1)
    {
        this->replace.push_back('\\');
    }
}

bool Replace::work()
{
    f.open(xmlname.c_str());

    if(!f.is_open())
    {
        return false;
    }

    while(!f.eof())
    {
        f.getline(buf, 1024);
        str.append(buf);
        str.append("\n");
    }

    str.pop_back();

    // 从filname标签中截取filename
    filename_pos_start = str.find(filename_label_start.c_str());
    filename_pos_end = str.find(filename_label_end.c_str());
    filenameLength = filename_pos_end - filename_pos_start - filename_label_start.length();
    filename = str.substr(filename_pos_start + filename_label_start.length(), filenameLength);

    // 将path标签中的文件路径替换为定义的路径加上文件名
    path_pos_start = str.find(path_label_start.c_str());
    path_pos__end = str.find(path_label__end.c_str());
    pathLength = path_pos__end - path_pos_start - path_label_start.length();
    str.replace(path_pos_start + path_label_start.length(), pathLength, (replace + filename).c_str());

    f.clear();
    f.seekp(0, std::ios::beg);
    f << str;
    f.close();

    return true;
}

getfiles.h

#include <iostream>
#include <vector>
#include <string>
#include <io.h>

void getFiles(std::string path, std::vector<std::string>& files)
{
    long long hFile = 0;
    struct _finddata_t fileinfo;
    std::string p;

    if((hFile = _findfirst(p.assign(path).append("\\*").c_str(), &fileinfo)) !=  -1)
    {
        do
        {
            if((fileinfo.attrib &  _A_SUBDIR))
            {
                if(strcmp(fileinfo.name,".") != 0  &&  strcmp(fileinfo.name,"..") != 0)
                {
                    getFiles(p.assign(path).append("\\").append(fileinfo.name), files);
                }
            }
            else
            {
                std::string s = fileinfo.name;
                size_t lastPos = s.find_last_of(".");
                if(strcmp(s.substr(lastPos + 1).c_str(), "xml") == 0)
                {
                    files.push_back(p.assign(path).append("\\").append(fileinfo.name));
                    //files.push_back(p.assign(path).append(fileinfo.name));
                }
            }
        }while(_findnext(hFile, &fileinfo)  == 0);
        _findclose(hFile);
    }
}