 Real @-@ time holography is a second method of creating holographic interferograms . A holograph of the unstressed object is created . This holograph is illuminated with a reference beam to generate a hologram image of the object directly superimposed over the original object itself while the object is being subjected to some stress . The object waves from this hologram image will interfere with new waves coming from the object . This technique allows real time monitoring of shape changes . 
