Select these parameters to retrieve the area of the region of interest and to compute the area of objects relative to the area of the region of interest. AreaRef returns the reference area of the currently selected regions in the image or, if no selection is made, the area of the whole image in calibrated units. AreaRatio returns the ratio between the area of objects and the reference area. If the region of interest or objects contain holes, the holes do not deposit to AreaRef or AreaRatio.