opencv下图像的旋转操作，需要安装最新版本的opencv-opencv image under the rotation operation, the need to install the latest version of opencv

这个函数旋转是改进刘瑞祯的例子，在旋转后不会改变原图像的位置，很有用-This function is to improve the rotation example Rui Chen, in the rotation would not change the location of the original image, very useful! !