cvLoadImage

cvLoadImage( filename, -1 ); 默认读取图像的原通道数

cvLoadImage( filename, 0 ); 强制转化读取图像为灰度图

cvLoadImage( filename, 1 ); 读取彩色图

例：将读入图像强制转换为灰度图像显示

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

int main(int argc, char **argv)
{
    if (argc != 2)
        return -1;
    /*强制转换为灰度图像*/
    IplImage *img = cvLoadImage(argv[1], 0);
    cvNamedWindow("example");
    cvShowImage("example", img);
    cvWaitKey(0);
    cvReleaseImage(&img);
    cvDestroyWindow("example");
    return 0;
}