opencv removes small areas of connected areas

#include "opencv.hpp"

#include "iostream"

using namespace std;

using namespace cv;

int main()

{

Mat srcImage, grayImage, dstImage,imgHSVMask;

int size = 800; //area factor

//srcImage = imread("");

/*imshow("original image", srcImage).

cvtColor(srcImage, grayImage, COLOR_RGB2GRAY);

threshold(grayImage, dstImage, 100, 255, THRESH_BINARY);

imshow("binary image", dstImage);*/

Mat img = imread("");

cvtColor(img, grayImage, COLOR_RGB2GRAY);

threshold(grayImage, imgHSVMask, 100, 255, THRESH_BINARY);

//imshow("Original image", imgHSVMask);

Mat element = getStructuringElement(MORPH_RECT, Size(3, 3)); // for the highlighted section

erode(imgHSVMask, imgHSVMask, element);

imshow("Corrosion", imgHSVMask);

// Extraction of connected areas and elimination of small connected areas

vector<vector<Point>> contours; //container for binary image contours

vector<Vec4i> hierarchy; //4 int vectors representing the index numbers of the back, front, parent, and child, respectively

findContours(imgHSVMask, contours, hierarchy,RETR_LIST, CHAIN_APPROX_NONE); // detect all contours

//(remove_if((), (),[](const vector<Point>& c) {return contourArea(c) < 800; }), ()); // Delete element

// Display the image and save it

/*(0);

drawContours(imgHSVMask, contours, -1, Scalar(255), FILLED);

imshow("Processing Map", imgHSVMask); */

Mat ImageContours = Mat::zeros((), CV_8UC1); //plotting

Mat ImgContours= Mat::zeros((), CV_8UC1);

vector<vector<Point>>::iterator k; // iterator that accesses container data

for (k = (); k ! = ();) // traverse the container, set the area factor

{

if (contourArea(*k, false) < size)

{// Deletes the specified element, returning an iterator pointing to the position of the next element of the deleted element.

k = (k);

}

else

++k;

}

//contours[i] represents the ith contour, contours[i].size() represents all pixel points on the ith contour

for (int i = 0; i < (); i++)

{

for (int j = 0; j < contours[i].size(); j++)

{

//Get the coordinates of the points on the contour.

Point P = Point(contours[i][j].x, contours[i][j].y);

<uchar>(P) = 255;

}

drawContours(ImageContours, contours,i, Scalar(255), -1, 8);

}

imshow("Contours", ImageContours);

imshow("Contour Points Collection", ImgContours);

waitKey(0);

return 0;

}