brightness.cpp

#include "opencv2/highgui/highgui.hpp"
#include <iostream>

using namespace cv;
using namespace std;

int truncate(int value)
{
    if(value<0)
      value = 0;
    else if(value > 255)
      value = 255;
    
    return value;
}
int main( int argc, const char** argv )
{
     Mat img = imread("Image.png", CV_LOAD_IMAGE_COLOR);

     if (img.empty())
     {
              cout << "Image cannot be loaded..!!" << endl;
              return -1;
     }

     CV_Assert(img.depth() == CV_8U);
     unsigned char *input = (unsigned char*) (img.data);
     /// new matrix 
     Mat outputImg(img.rows,img.cols,CV_8U);
     unsigned char *output = (unsigned char*) (outputImg.data);
     
     for(int i = 0; i < img.rows; ++i){
         for(int j = 0; j < img.cols;++j){
	     int b = input[i*img.step+j*3]; 
	     int g = input[i*img.step+j*3+1];
	     int r = input[i*img.step+j*3+2];
	     output[i*outputImg.step+j] = static_cast<unsigned char>(truncate(b+70));
	     output[i*outputImg.step+j+1] = static_cast<unsigned char>(truncate(g+70));
	     output[i*outputImg.step+j+2] = static_cast<unsigned char>(truncate(r+70));
	 }  
     }
//      cout << "Size of Matrix " << img.size() << " and " << newImg.size() << endl;
//      cout << "Rows of Matrix " << img.size().width << endl;
//      cout << "Coloums of Matrix " << img.size().height << endl;
//      cout << "Values " << img.total() << endl;
     
     //Mat imgH = img + Scalar(75, 75, 75); //increase the brightness by 75 units
     //img.convertTo(imgH, -1, 1, 75);

     //Mat imgL = img + Scalar(-75, -75, -75); //decrease the brightness by 75 units
     //img.convertTo(imgL, -1, 1, -75);

     namedWindow("Original Image", CV_WINDOW_AUTOSIZE);
     namedWindow("High Brightness", CV_WINDOW_AUTOSIZE);
//      namedWindow("Low Brightness", CV_WINDOW_AUTOSIZE);

     imshow("Original Image", img);
     imshow("High Brightness", outputImg);
//      imshow("Low Brightness", imgL);

     waitKey(0);

     destroyAllWindows(); //destroy all open windows

     return 0;
}