OpenCV object/color detection

//Color.h
#pragma once
enum Color {BLUE, RED, GREEN, YELLOW, PURPLE};

//Ball.h
#pragma once

#include "Color.h"
#include <opencv2/core/types.hpp>

class Ball
{
public:
    Color color;
    cv::Point position;
    cv::Rect rect;

    Ball();
    Ball(Color color, cv::Rect rect, int x, int y);

};

//Ball.cpp
#include "Ball.h"

Ball::Ball(){
}

Ball::Ball(Color color, cv::Rect rect, int x, int y){
    this->color = color;
    this->rect = rect;
    this->position = cv::Point(x, y);
}

//main.cpp
#include <opencv2/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>

#include "Ball.h"

cv::Scalar yellowLow = cv::Scalar(25, 130, 180);
cv::Scalar yellowHigh = cv::Scalar(45, 255, 255);
cv::Scalar greenLow = cv::Scalar(46, 40, 40);
cv::Scalar greenHigh = cv::Scalar(70, 255, 255);
cv::Scalar blueLow = cv::Scalar(100, 150, 150);
cv::Scalar blueHigh = cv::Scalar(140, 255, 255);
cv::Scalar purpleLow = cv::Scalar(148, 117, 89);
cv::Scalar purpleHigh = cv::Scalar(152, 255, 255);
cv::Scalar redLow = cv::Scalar(170, 140, 160);
cv::Scalar redHigh = cv::Scalar(180, 255, 255);

std::vector<Ball> balls;

void GetBalls(cv::Mat img, cv::Scalar low, cv::Scalar high, Color color) {
    cv::Mat mask;
    cv::inRange(img, low, high, mask);
    std::vector<std::vector<cv::Point> > contours;
    cv::findContours(mask, contours, cv::RETR_EXTERNAL, cv::CHAIN_APPROX_SIMPLE);

    for (size_t i = 0; i < contours.size(); i++)
    {
        cv::Rect boundRect = boundingRect(contours[i]);
        if (boundRect.area() > 350 && (boundRect.width < 70 || boundRect.height < 70)) {
            balls.emplace_back(color, boundRect, boundRect.x + boundRect.width / 2, boundRect.y + boundRect.height / 2);
        }
    }
}

void drawBalls(cv::Mat background) {
    for (size_t i = 0; i < balls.size(); i++) {
        switch (balls[i].color) {
        case RED:
            rectangle(background, balls[i].rect.tl(), balls[i].rect.br(), CV_RGB(255, 0, 0), 2);
            break;
        case BLUE:
            rectangle(background, balls[i].rect.tl(), balls[i].rect.br(), CV_RGB(0, 0, 255), 2);
            break;
        case GREEN:
            rectangle(background, balls[i].rect.tl(), balls[i].rect.br(), CV_RGB(0, 255, 0), 2);
            break;
        case YELLOW:
            rectangle(background, balls[i].rect.tl(), balls[i].rect.br(), CV_RGB(255, 255, 0), 2);
            break;
        case PURPLE:
            rectangle(background, balls[i].rect.tl(), balls[i].rect.br(), CV_RGB(128, 0, 128), 2);
            break;
        }
    }
}


int main(){
    cv::Mat target = cv::imread("target.jpg"); //cv::IMREAD_COLOR

    cv::Mat background;
    target.copyTo(background);

    cv::cvtColor(target, target, cv::COLOR_BGR2HSV);

    cv::rectangle(target, cv::Point(0, 0), cv::Point(640, 30), (0, 0, 0), cv::FILLED);

    GetBalls(target, yellowLow, yellowHigh, Color::YELLOW); //find yellow balls
    GetBalls(target, blueLow, blueHigh, Color::BLUE); //find blue balls
    GetBalls(target, redLow, redHigh, Color::RED); //find red balls
    GetBalls(target, greenLow, greenHigh, Color::GREEN); //find green balls
    GetBalls(target, purpleLow, purpleHigh, Color::PURPLE); // find purple balls
    drawBalls(background);

    cv::imshow("contours", background);
    cv::waitKey(0);
}