A method and apparatus (20) for recognizing and determining a location of an object (40) in an area of interest (31) comprises an imaging device (61) for obtaining an image of the area of interest. At least three identifying marks (104) are located at predetermined positions in the area of interest (31). The apparatus (20) also comprises a memory (78) in which the predetermined positions of the at least three identifying marks (104) are stored. A controller (80) determines whether the imaging device (61) is calibrated properly by analyzing the image obtained by the imaging device to determine whether positions of the at least three identifying marks (104) in the obtained image correspond to the predetermined positions stored in the memory (78). The controller (80) is also adapted to determine whether a view of the area of interest (31) from the imaging device (61) is obstructed.