An apparatus and method for measuring loop height of overlapping bonded wires, interconnecting the pads of a single or stacked silicon chips to the pads of a substrate taking the steps of: focussing of an optical assembly at multiple points of the bond wire including overlapping bond wires, capturing an image of the bond wire at each of the predetermined focused points; calculating the height of each point of the wire with respect to a reference plane; and tabulating the height data using the X, Y and Z coordinates.