how to remove small contour from the frame? - c++

Question

I have written the program to detect the object in the water(swimming pool). But I am getting lot of other contours like as shown in this screenshot. But this is the actual image. Please help me to get rid of other unwanted contours detected in the video. Below is the code that I have written.
#include "opencv2/objdetect/objdetect.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>
#include <stdio.h>
using namespace std;
using namespace cv;
string window_name = "Captured rectangle block";
RNG rng(12345);
double fps;
int thresh = 100;
int main( int argc, const char** argv )
{
VideoCapture cap("IMGP2850.MOV"); // open the video file for reading
if ( !cap.isOpened() ) // if not success, exit program
{
cout << "Cannot open the video file" << endl;
return -1;
}
fps = cap.get(CV_CAP_PROP_FPS); //get the frames per seconds of the video
cout << "Frame per seconds : " << fps << endl;
double dWidth = cap.get(CV_CAP_PROP_FRAME_WIDTH);
double dHeight = cap.get(CV_CAP_PROP_FRAME_HEIGHT);
Size S(dWidth,dHeight);
while(1)
{
Mat frame;
Mat threshold_output;
int skip_frame = 4;
while(skip_frame)
{
printf("inside while loop\n");
bool bSuccess = cap.read(frame); // read a new frame from video
skip_frame--;
if (!bSuccess) //if not success, break loop
{
cout << "Cannot read the frame from video file" << endl;
break;
}
}
//-- 3. Apply the classifier to the frame
if( frame.empty() )
{ printf(" --(!) No captured frame -- Break!"); break; }
std::vector<Rect> faces;
Mat frame_gray;
cvtColor( frame, frame_gray, CV_BGR2GRAY );
equalizeHist( frame_gray, frame_gray);
blur( frame_gray, frame_gray, Size(3,3) );
vector<vector<Point> > contours;
vector<Vec4i> hierarchy;
printf("before finding countrs\n");
threshold( frame_gray, threshold_output, thresh, 255, THRESH_BINARY );
findContours( threshold_output, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0));
vector<vector<Point> > contours_poly( contours.size() );
vector<Rect> boundRect( contours.size() );
vector<Point2f>center( contours.size() );
vector<float>radius( contours.size() );
// contours.resize(contours.size());
printf("after finding countrs\n");
for( unsigned int i = 0; i < contours.size(); i++ )
{
printf("inside for loop\n");
approxPolyDP( Mat(contours[i]), contours_poly[i], 3, true );
printf("after poly\n");
boundRect[i] = boundingRect( Mat(contours_poly[i]) );
printf("after bondrec\n");
minEnclosingCircle( (Mat)contours_poly[i], center[i], radius[i] );
}
Mat drawing = Mat::zeros( threshold_output.size(), CV_8UC3 );
for( unsigned int i = 0; i< contours.size(); i++ )
{
Scalar color = Scalar( rng.uniform(0, 255), rng.uniform(0,255), rng.uniform(0,255) );
drawContours( drawing, contours_poly, i, color, 1, 8, vector<Vec4i>(), 0, Point() );
rectangle( drawing, boundRect[i].tl(), boundRect[i].br(), color, 2, 8, 0 );
circle( drawing, center[i], (int)radius[i], color, 2, 8, 0 );
}
/// Show in a window
namedWindow( "Contours", CV_WINDOW_AUTOSIZE );
imshow( "Contours", drawing );
int c = waitKey(10);
if( (char)c == 'c' ) { break; }
}
return 0;
}