An apparatus for monitoring and replenishing an inventory of goods includes a first inventory area and a first movable structure having a first optical code associated with the first distinct inventory area. The first movable structure is placed in a replenishment signaling area after a supply of goods in the inventory area has been depleted. Boundary optical codes are disposed near a boundary of the replenishment signaling area. A camera generates periodic images of the replenishment signaling area and the boundary optical codes. A computer processor detects the boundary optical codes in the images and determines a boundary line of the replenishment signaling area based thereon. The processor determines a spatial relationship between the first optical code and the boundary line in the images and generates a replenishment notification based on the spatial relationship. The replenishment notification indicates that the supply of the first type of goods needs to be replenished.