Units of centroid in regionprops

Hi, I calculated the centroid of some of the blobs in my image using centroid property of regionprops. It gave me x and y coordinates as:

[36.945, 129.114]

Can anyone explain me, what is the unit of this centroid? Since it is in decimals, I think it is not in pixels.

For additional information, my image size is 330 * 330

Please reply.

Thanks!