OpenCV and reading image with floating point data

Question

I use OpenCV to read the image. Then I use Matlab to load the same image. Then I display the images. For OpenCV loaded image, the image is has no picture inside and just gray plane. For Matlab loaded image, it has the image what I want. The image pixel values are very small floating point data like 0.0021. The code I used to load the image is shown as follow.

`Mat image(IMAGE_ROW, IMAGE_COL, CV_64FC3);
Mat  gray(IMAGE_ROW, IMAGE_COL, CV_64FC1);
image = imread(filespath, CV_LOAD_IMAGE_COLOR );// Read the file
cv::imshow("Image", image);
cvtColor( image, gray, CV_BGR2GRAY, 1);
cv::imshow("gray", gray);`

Why I can't have the same image as loaded by Matlab?

Answer 1

well you can't do it with imwrite()/imread() as stated before.

but you can save/load floating point Mats using the FileStorage, like this:

Mat fm = Mat::ones(3,3,CV_32FC3); // dummy data

FileStorage fs("my.yml", FileStorage::WRITE );
fs << "mat1" << fm;  //choose any key here, just be consistant with the one below

and read back in:

Mat fm;
FileStorage fs("my.yml", FileStorage::READ );
fs["mat1"] >> fm;