Python OpenCV - Find black areas in a binary image
After inverting binary image to turn black to white areas, apply cv.FindContours function. It will give you boundaries of the region you need.
Later you can use cv.BoundingRect to get minimum bounding rectangle around region. Once you got the rectangle vertices, you can find its center etc.
Or to find centroid of region, use cv.Moment function after finding contours.  Then use cv.GetSpatialMoments in x and y direction. It is explained in opencv manual. 
To find area, use cv.ContourArea function.
There is any method/function in the python wrapper of Opencv that finds black areas in a binary image? (like regionprops in Matlab)
Up to now I load my source image, transform it into a binary image via threshold and then invert it to highlight the black areas (that now are white).
I can't use third party libraries such as cvblobslob or cvblob