sift 图像拼接 static IplImage* convert_to_gray32( IplImage* img ) { IplImage* gray8, * gray32; gray32 = cvCreateImage( cvGetSize(img), IPL_DEPTH_32F, 1 ); if( img->nChannels == 1 ) gray8 = cvClone( img ); else { gray8 = cvCreateImage( cvGetSize(img), IPL_DEPTH_8U, 1 ); cvCvtColor( img, gray8