opencv c++ 将ipl更改为mat累加

Question

i tried to change code ipl to mat

but failed

i use opencv 4.1.2

this sample uses opencv 2.4.13

https://jadeshin.tistory.com/entry/cvAcc에-의한-배경-영상-계산

i can't use ipl

so i changed

 #include <opencv2\opencv.hpp>
 #include <opencv2\highgui\highgui.hpp>
 #include <opencv2\core\mat.hpp>
 #include <opencv2\imgproc.hpp>
 #include <iostream>

using namespace cv;
using namespace std;

int main()
{
    VideoCapture cap("ball.avi");
    if (!cap.isOpened())
    {
            cout << "file not found." << endl;
            return 0;
    }
    Mat image;
    Size size = Size((int)CAP_PROP_FRAME_WIDTH, (int)CAP_PROP_FRAME_HEIGHT);
    Mat grayImage(size, CV_8UC1);
    Mat sumImage(size, CV_32FC1);
    sumImage.setTo(Scalar::all(0));
    int nFrameCount = 0;
    for (;;)
    {
            cap.read(image);
            if (image.empty())
            {
                    cout << "could'nt capture" << endl;
                    break;
            }

            cvtColor(image, grayImage, COLOR_BGR2GRAY);
            accumulate(grayImage, sumImage, NULL); //here is error
            imshow("grayImage", grayImage); 
            char chKey = waitKey(50);
            if (chKey == 27)
                    break;
            nFrameCount++;
    }
    convertScaleAbs(sumImage, sumImage, 1.0 / nFrameCount);
    imwrite("ballBkg.jpg", sumImage);
    destroyAllWindows();
    return 0;
}

nothing wrong to compile but wrong to excute

i did also try, catch

but also failed

what's wrong with accumulate?

Answer 1

C++ version of accumulate void accumulate(InputArray src, InputOutputArray dst, InputArray mask=noArray() )

your are passing NULL instead of noArray() . so just do :

accumulate(grayImage, sumImage);  


 cv::noArray() is an empty Mat not NULL.

Edit :

Also change

Size size = Size((int)CAP_PROP_FRAME_WIDTH, (int)CAP_PROP_FRAME_HEIGHT);

to

Size size = Size((int)cap.get(CV_CAP_PROP_FRAME_WIDTH), (int)cap.get(CV_CAP_PROP_FRAME_HEIGHT));