vtk中的图片传给opencv的mat操作

vtkImageData* image = windowToImageFilter->GetOutput(); 
// Check number of components. 
const int numComponents =  image->GetNumberOfScalarComponents(); // 3
// Construct the OpenCv Mat 
int dims[3]; 
image->GetDimensions(dims); 
cv::Mat openCVImage(dims[0], dims[1], CV_8UC3, image->GetScalarPointer()); // Unsigned int, 3 channels 

cvtColor(openCVImage, openCVImage, CV_BGRA2GRAY); 

// Flip because of different origins between vtk and OpenCV 
cv::flip(openCVImage,openCVImage, 0); 

I think vtk is giving me the image in BGRA, so I perform a conversion from BGRA to GRAY. Doing it to RGB did not give me the expected results, but since I just need a black and white image I did not did deeper.
If you need to keep colors, just figure out if vtk is storing the image in RGBA, BGRA or how and transform into RGB.
网上搜了一下，用vtk得到的图像传给opencv使用，资料里说明，vtk的图像可能是RGBA的4通道，所以用转换一下成灰度图像。并且两个库得到图像的坐标也不一样，所以要对图片进行翻转操作。

再来对vtk图像进行了解，vtkChangeImageInformation可以作为管线中的一个filter来修改图像信息。利用这个filter可以修改图像的原点，像素间隔以及范围起点（extent），另外还可以对图像平移缩放等操作。【2】

参考资料：
【1】

http://vtk.1045678.n5.nabble.com/From-vtkImageData-to-Iplimage-OpenCV-td5716020.html
【2】

http://blog.youkuaiyun.com/shenziheng1/article/details/54646862