1

I am now doing image registration with ITK library. I read source images with OpenCV, then convert them to ITKImage; after registration, I convert the result to CVMat and use imwrite to store it.

However, ITKOmageToCVMat always gives a white image (show by imshow), and after imwrite, the result isn't stored in the folder. That's so strange...

Below is my code:

cv::Mat img1 = imread(argv[1], IMREAD_GRAYSCALE);
cv::Mat img2 = imread(argv[2], IMREAD_GRAYSCALE);

typedef float  PixelType;
const unsigned int Dimension = 2;
typedef itk::Image< PixelType, Dimension > FixedImageType;
typedef itk::Image< PixelType, Dimension > MovingImageType;
typedef itk::OpenCVImageBridge BridgeType;
FixedImageType::Pointer fixedImage = BridgeType::CVMatToITKImage<FixedImageType>(img1);
MovingImageType::Pointer movingImage = BridgeType::CVMatToITKImage<MovingImageType>(img2);

Mat img3 = itk::OpenCVImageBridge::ITKImageToCVMat<MovingImageType>(movingImage);
display("moving image", img3);
string filename3 = "img3";
imwrite(filename3, img3);

Even without registration, just convert an image from CVMat to ITKImage, then convert back, it doesn't work.... Do you have any idea? Thank you :)

Kaiwen
  • 137
  • 1
  • 9

1 Answers1

1

Your code is almost fine and it should work but you have to consider 2 things. One is your images' type. When you read an image from hard disk, pixels' values are between 0 and 255 in "uchar" type but you defined the ITK's images in float type { typedef float PixelType; }, so when you convert them back to cv::Mat , they're still float, but their values are more than 1 (0~255) and the maximum value of a float image for "imshow" command, has to be "1", so you just need to divide your image to 255: imshow("moving image", img3/255);

The second problem is the filename: string filename3 = "img3"; you have to determine the image's format to save, like string filename3 = "img3.bmp";

MeiH
  • 1,763
  • 11
  • 17