'**SUMMARY**
Return the centroid (mass-determined center) of the blob. Note that this is differnt from the bounding box center.
**RETURNS**
An (x,y) tuple that is the center of mass of the blob.
**EXAMPLE**
>>> img = Image("lenna")
>>> blobs = img.findBlobs()
>>> img.drawCircle((blobs[-1].x,blobs[-1].y),10,color=Color.RED)
>>> img.drawCircle((blobs[-1].centroid()),10,color=Color.BLUE)
>>> img.show()'

def centroid(self):

    return ((self.m10 / self.m00), (self.m01 / self.m00))
