# OpenCV Distance c++

Goodmorning everyone. I am making a small program that allows me to go and determine the area of the object and then to determine the distance of this object. To determine the distance of the object. I determined the area and measured the distance with the meter, repeating the same operation several times. At this point trying with any other object, I do not understand why the part on the distance is not printed on the screen.

```
void trackFilteredObject(int &x, int &y, Mat threshold, Mat &cameraFeed){
Mat temp;
threshold.copyTo(temp);
//these two vectors needed for output of findContours
std::vector< std::vector<Point> > contours;
std::vector<Vec4i> hierarchy;
//find contours of filtered image using openCV findContours function
findContours(temp,contours,hierarchy,CV_RETR_CCOMP,CV_CHAIN_APPROX_SIMPLE );
//use moments method to find our filtered object
double refArea = 0;
bool objectFound = false;
if (hierarchy.size() > 0) {
int numObjects = hierarchy.size();
//if number of objects greater than MAX_NUM_OBJECTS we have a noisy filter
if(numObjects<MAX_NUM_OBJECTS){
for (int index = 0; index >= 0; index = hierarchy[index][0]) {
Moments moment = moments((cv::Mat)contours[index]);
double area = moment.m00;
//if the area is less than 20 px by 20px then it is probably just noise
//if the area is the same as the 3/2 of the image size, probably just a bad filter
//we only want the object with the largest area so we safe a reference area each
//iteration and compare it to the area in the next iteration.
if(area>MIN_OBJECT_AREA && area<MAX_OBJECT_AREA && area>refArea){
x = moment.m10/area;
y = moment.m01/area;
xCoord=x;
yCoord=y;
objectFound = true;
refArea = area;
std::cout<<area<<std::endl;
//DISTANCE HERE
double dist;
if (refArea==0) {
cout << "\nArea is egual to 0" << endl;
}
else if (refArea>0 && refArea<=295) {
dist = 50;
cout << "\nThe distance of the object is " << dist << " cm\n" <<endl;
}
else if (refArea>295 && refArea<=320) {
dist = 65;
cout << "\nThe distance of the object is " << dist << " cm\n" <<endl;
}
else if (refArea>320 && refArea<=335) {
dist = 95;
cout << "\nThe distance of the object is " << dist << " cm\n" <<endl;
}
else {
cout << "\nDistance no determinate" <<endl;
}
// end of distance
} else objectFound = false;
}
//let user know you found an object
if(objectFound ==true) {
putText(cameraFeed,"Tracking Object",Point(0,50),2,1,Scalar(0,255,0),2);
//draw object location on screen
drawObject(x,y,cameraFeed);
}
}else putText(cameraFeed,"TOO MUCH NOISE! ADJUST FILTER",Point(0,50),1,2,Scalar(0,0,255),2);
}
}
```

Can you help me to understand why nothing relative to distance is printed? Thank you

go and debug it.

Ok now it works. But in your opinion can i use this code to measure distance?

if you meant "real world distance" : https://en.wikipedia.org/wiki/Pinhole...