opencv c++ change ipl to mat accumulate - c++

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));