Read in image file sequence in C++ w/o using opencv

Question

Given image files

lights000.rgbe
lights001.rgbe
lights002.rgbe
...
lights899.rgbe

Are all located in a single subfolder. What is the best way to read one file then the next?

Given that my read command for .rgbe is called readHDR(char* filename)

I have seen several questions regrading this problem but they all use OpenCV. I am not using opencv and .rgbe is not even a supported OpenCV file extension so that method wouldn't even work.

I saw the following code from a different question:

char* Dataset_Dir( "C:/Data/" ); // Or take it from argv[1]
cv::Mat normal_matrix;
std::vector<cv::Mat>* image_stack;
for( int i=1; i<=endNumber; ++i )
{
    // Gives the entire stack of images for you to go through
    image_stack->push_back(cv::imread(std::format("%s/%03d-capture.png", Dataset, i), CV_LOAD_IMAGE_COLOR)); 

    normal_matrix = cv::imread(std::format("%s/%03d-capture.png", Dataset, i), CV_LOAD_IMAGE_COLOR);
}

But I cannot find any information on the std::format command or the Dataset_Dir.

Any advice for even how to split the file name string into three parts would be really helpful.

Split into:

 char Name = "lights";
 int Num  = "000";
 char File = ".rgbe;

This is not a duplicate cause this questions - http://stackoverflow.com/questions/236129/how-to-split-a-string-in-c does not answer mine. It explains how to split a string with spaces — Maggick, Oct 06 '14 at 21:18
read [this answer](http://stackoverflow.com/a/236803/2296458) in that post. You may use any delimiter you would like. Try reading the whole post before jumping to defense. — Cory Kramer, Oct 06 '14 at 21:19
Well, you want to extract the `Num` value also. There's no delimiter you can use, just you can check if the filename in question starts with `"lights"`, and take the rest up to the `'.'` as the `Num` value. — πάντα ῥεῖ, Oct 06 '14 at 21:21
But the filename is also not fixed. So what would be the best way to find what that first file is in the folder — Maggick, Oct 06 '14 at 21:23

score 1 · Accepted Answer · answered Oct 06 '14 at 21:47

Here's a simple solution, how to split your filename strings by the criteria you specified:

#include <iostream>
#include <string>
#include <sstream>

using namespace std;

int main() {
    istringstream filename("lights042.rgbe");
    string Name;
    int Num;
    string File;

    while(filename && !isdigit(filename.peek())) {
        char c;
        filename >> c;
        Name += c;
    }

    filename >> Num;
    filename >> File;

    cout << "Name = '" << Name << "'" << endl;
    cout << "Num = " << Num << endl;
    cout << "File = '" << File << "'" << endl;

    return 0;
}

Output

Name = 'lights'
Num = 42
File = '.rgbe'

See the live demo please.

Read in image file sequence in C++ w/o using opencv

1 Answers1