Someone please help thanks

#include <sstream>
#include <string>
#include <iostream>
#include <opencv\highgui.h>
#include <opencv\cv.h>

using namespace cv;
//initial min and max HSV filter values.
//these will be changed using trackbars
int H_MIN = 0;
int H_MAX = 256;
int S_MIN = 0;
int S_MAX = 256;
int V_MIN = 0;
int V_MAX = 256;
//default capture width and height
const int FRAME_WIDTH = 640;
const int FRAME_HEIGHT = 480;
//max number of objects to be detected in frame
const int MAX_NUM_OBJECTS=50;
//minimum and maximum object area
const int MIN_OBJECT_AREA = 40*40;
//names that will appear at the top of each window
const string windowName = "Original Image";
const string windowName1 = "HSV Image";
const string windowName2 = "Thresholded Image";
const string windowName3 = "After Morphological Operations";
const string trackbarWindowName = "Trackbars";
void on_trackbar( int, void* )
{//This function gets called whenever a
    // trackbar position is changed

string intToString(int number){

    std::stringstream ss;
    ss << number;
    return ss.str();
void createTrackbars(){
    //create window for trackbars

    //create memory to store trackbar name on window
    char TrackbarName[50];
    sprintf( TrackbarName, "H_MIN", H_MIN);
    sprintf( TrackbarName, "H_MAX", H_MAX);
    sprintf( TrackbarName, "S_MIN", S_MIN);
    sprintf( TrackbarName, "S_MAX", S_MAX);
    sprintf( TrackbarName, "V_MIN", V_MIN);
    sprintf( TrackbarName, "V_MAX", V_MAX);
    //create trackbars and insert them into window
    //3 parameters are: the address of the variable that is changing when the trackbar is moved(eg.H_LOW),
    //the max value the trackbar can move (eg. H_HIGH), 
    //and the function that is called whenever the trackbar is moved(eg. on_trackbar)
    //                                  ---->    ---->     ---->      
    createTrackbar( "H_MIN", trackbarWindowName, &H_MIN, H_MAX, on_trackbar );
    createTrackbar( "H_MAX", trackbarWindowName, &H_MAX, H_MAX, on_trackbar );
    createTrackbar( "S_MIN", trackbarWindowName, &S_MIN, S_MAX, on_trackbar );
    createTrackbar( "S_MAX", trackbarWindowName, &S_MAX, S_MAX, on_trackbar );
    createTrackbar( "V_MIN", trackbarWindowName, &V_MIN, V_MAX, on_trackbar );
    createTrackbar( "V_MAX", trackbarWindowName, &V_MAX, V_MAX, on_trackbar );

void drawObject(int x,int y,Mat &frame){

    cv::putText(frame,intToString(x)+ " , " + intToString(y),cv::Point(x,y+20),1,1,Scalar(0,255,0));

void morphOps(Mat &thresh){

    //create structuring element that will be used to "dilate" and "erode" image.
    //the element chosen here is a 3px by 3px rectangle

    Mat erodeElement = getStructuringElement( MORPH_RECT,Size(3,3));
    //dilate with larger element so make sure object is nicely visible
    Mat dilateElement = getStructuringElement( MORPH_RECT,Size(8,8));



void trackFilteredObject(Mat threshold,Mat HSV, Mat &cameraFeed){

    int x,y;

    Mat temp;
    //these two vectors needed for output of findContours
    vector< vector<Point> > contours;
    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
            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.
                    x = moment.m10/area;
                    y = moment.m01/area;

                    objectFound = true;

                }else objectFound = false;

            //let user know you found an object
            if(objectFound ==true){
                //draw object location on screen

        }else putText(cameraFeed,"TOO MUCH NOISE! ADJUST FILTER",Point(0,50),1,2,Scalar(0,0,255),2);

int main(int argc, char* argv[])
    //if we would like to calibrate our filter values, set to true.
    bool calibrationMode = true;

    //Matrix to store each frame of the webcam feed
    Mat cameraFeed;
    Mat threshold;
    Mat HSV;

        //create slider bars for HSV filtering
    //video capture object to acquire webcam feed
    VideoCapture capture;
    //open capture object at location zero (default location for webcam);
    //set height and width of capture frame
    //start an infinite loop where webcam feed is copied to cameraFeed matrix
    //all of our operations will be performed within this loop
        //store image to matrix;
        //convert frame from BGR to HSV colorspace

        //if in calibration mode, we track objects based on the HSV slider values.

        //show frames 


        //delay 30ms so that screen can refresh.
        //image will not appear without this waitKey() command

    return 0;

The compiler does not know where COLOR_BGR2HSV is defined.
I suggest you take a look at the documentation for the OpenCV library and see if you can find the header file that COLOR_BGR2HSV is defined in and ensure it is #included in your source file.

Second thoughts:
From a quick poke around on the net I've found this:
Which contains the following line:
cvCvtColor(frame, imgHSV, CV_BGR2HSV); //Change the color format from BGR to HSV
Which looks as if it is exactly what you are doing at the line where you are getting your error. So perhaps COLOR_BGR2HSV is actually incorrect. Perhaps you should be using CV_BGR2HSV instead!

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