【OpenCV学习】图像亮度、对比度调节（伽马校正）

 
#include "cv.h"
#include "highgui.h"
#include <stdio.h>
int ImageAdjust(IplImage *src,IplImage *dst,
                double low,double high,        //x direction
                double bottom,double top,    //y direction
                double gamma);
int main(void)
{
    char *filename="lena.jpg";
    IplImage *dst,*src = /blog.armyourlife.info/cvLoadImage(filename,0);
    if(!src)
    {
        printf("Couldn't seem to Open %s, sorry/n",filename);
        return -1;
    }
   
  cvNamedWindow( "src", 1 );
    cvNamedWindow( "result", 1 );
   
    // Image adjust
    dst = cvCloneImage(src);
    // 输入参数 [0,0.5] 和 [0.5,1], gamma=1
    if( ImageAdjust( src, dst, 0, 0.5, 0.5, 1, 1)!=0)
        return -1;
   
    cvShowImage( "src", src );
    cvShowImage( "result", dst );
    cvWaitKey(0);
    cvDestroyWindow("src");
    cvDestroyWindow("result");
    cvReleaseImage( &src );
    cvReleaseImage( &dst );
   
    return 0;
}
int ImageAdjust(IplImage* src, IplImage* dst,
        double low, double high,   // X方向：low and high are the intensities of src
        double bottom, double top, // Y方向：mapped to bottom and top of dst
        double gamma )
{
    double low2 = low*255;
    double high2 = high*255;
    double bottom2 = bottom*255;
    double top2 = top*255;
    double err_in = high2 - low2;
    double err_out = top2 - bottom2;
    int x,y;
    double val;
    if(low<0 && low>1 && high <0 && high>1&&
    bottom<0 && bottom>1 && top<0 && top>1 && low>high)
        return -1;
      // intensity transform
    for( y = 0; y < src->height; y++)
    {
        for (x = 0; x < src->width; x++)
        {
            val = ((uchar*)(src->imageData + src->widthStep*y))[x];
            val=pow((val - low2)/err_in, gamma)*err_out+bottom2;
            if(val>255)
                val=255;
            if(val<0)
                val=0; // Make sure src is in the range [low,high]
            ((uchar*)(dst->imageData + dst->widthStep*y))[x] = (uchar) val;
        }
    }
    return 0;
}