#include <iostream>
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc_c.h"
#include "opencv2/imgproc/imgproc.hpp"
#include <stdio.h>
using namespace std;
using namespace cv;

int main()
{

Mat newImg,img;
img=imread("img.jpeg");
cvtColor(img, newImg, CV_BGR2HSV);

imwrite("test.jpg", newImg);

vector<Mat> hsv_planes;
split(newImg, hsv_planes); //geting the color plans of image
int param = -70; // the value that I'm seting for V
    for (int y = 0; y < newImg.rows; y++) {
    for (int x = 0; x < newImg.cols; x++) {

        Vec3b pixel = hsv_planes[2].at<Vec3b>(y, x);
        pixel[0] = 0;
        pixel[1] = 0;
        pixel[2] = param;

        hsv_planes[2].at<Vec3b>(y, x) = pixel;

    }
}

    merge(hsv_planes, newImg);
Mat imagem;
cvtColor(newImg, imagem, CV_HSV2BGR);

imwrite("final.jpg", imagem);

    return 0;
}