【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;
}