Code for changing contrast of image

******code starts here********

/* compilation:

1. chmod +x contrast.cpp
2. g++ -ggdb pkg-config --cflags opencv -o basename contrast.cpp .cpp contrast.cpp pkg-config --libs opencv

Usage: ./contrast IMAGE.EXTENSION CONTRAST_ADDING_VALUE (eg: - ./contrast cat.jpg 100) */

include <cv.h>

include <highgui.h>

int main(int argc, char** argv)

{

IplImage* src;

src=cvLoadImage(argv[1],1);

int add = atoi(argv[2]);

cvAddS(src, cvScalar(add),src);

cvNamedWindow( "example", CV_WINDOW_AUTOSIZE );

cvShowImage( "example", src );

cvWaitKey();

return 0;

}

Hope this helps you :)

Code for changing contrast of image

******code starts here********

/* compilation: 
 
 
1. chmod +x contrast.cpp
 
contrast.cpp
2. g++ -ggdb pkg-config `pkg-config --cflags opencv opencv` -o basename `basename contrast.cpp .cpp .cpp` contrast.cpp pkg-config `pkg-config --libs opencv
opencv`
 
 
Usage: ./contrast IMAGE.EXTENSION CONTRAST_ADDING_VALUE
(eg: - ./contrast cat.jpg 100)
*/*/
 #include <cv.h>
 
include <cv.h>#include <highgui.h>
  
include <highgui.h>
 
int main(int argc, char** argv)argv)
{
IplImage* src;
src=cvLoadImage(argv[1],1);
 
{
 
IplImage* src;
 
src=cvLoadImage(argv[1],1);
 
 int add = atoi(argv[2]);atoi(argv[2]);
cvAddS(src, cvScalar(add),src);
 
cvAddS(src, cvScalar(add),src);
 
 cvNamedWindow( "example", CV_WINDOW_AUTOSIZE ););
  
 cvShowImage( "example", src ););
cvWaitKey();
 
cvWaitKey();
 
 return 0;
 
}0;
}

Code for changing contrast of image

******code starts here********

/* compilation: 

1. chmod +x contrast.cpp
2. g++ -ggdb `pkg-config --cflags opencv` -o `basename contrast.cpp .cpp` contrast.cpp `pkg-config --libs opencv`

Usage: ./contrast IMAGE.EXTENSION CONTRAST_ADDING_VALUE
CONTRAST_ADDING_VALUE BRIGHTNESS_ADDING_VALUE
(eg: - ./contrast cat.jpg 2 100)
*/

 #include <cv.h>
 #include <highgui.h>

int main(int #include <iostream>

using namespace cv;

double alpha; /**< Simple contrast control */
int beta;  /**< Simple brightness control */

int main( int argc, char** argv)

argv )
{

  IplImage* src;

  src=cvLoadImage(argv[1],1);


  int add = atoi(argv[2]);

  cvAddS(src, cvScalar(add),src);


  cvNamedWindow( "example", CV_WINDOW_AUTOSIZE  /// Read image given by user
 Mat image = imread( argv[1] );

  cvShowImage( "example", src  Mat new_image = Mat::zeros( image.size(), image.type() );

  cvWaitKey();


 /// Initialize values
 std::cout<<" Basic Linear Transforms "<<std::endl;
 std::cout<<"-------------------------"<<std::endl;
 std::cout<<"* Enter the alpha value [1.0-3.0]: ";std::cin>>alpha;
 std::cout<<"* Enter the beta value [0-100]: "; std::cin>>beta;

 /// Do the operation new_image(i,j) = alpha*image(i,j) + beta
 for( int y = 0; y < image.rows; y++ )
    { for( int x = 0; x < image.cols; x++ )
         { for( int c = 0; c < 3; c++ )
              {
      new_image.at<Vec3b>(y,x)[c] =
         saturate_cast<uchar>( alpha*( image.at<Vec3b>(y,x)[c] ) + beta );
             }
    }
    }

 /// Create Windows
 namedWindow("Original Image", 1);
 namedWindow("New Image", 1);

 /// Show stuff
 imshow("Original Image", image);
 imshow("New Image", new_image);

 /// Wait until user press some key
 waitKey();
 return 0;
}

Hope this helps you :)