The mapping between the Intensity Ratio on the image surface IR(x,y) and the displacement magnitude along the surface d(x,y) (Equation 7) for our blue laser system with = 0.47 micrometers. The Inset shows fringes of displacement amplitude on a cat tympanic membrane stimulated by a sound of 1270 Hz and 120 dB SPL. The white outline line shows the outline of the ossicular handle (the manubrium of the malleus) that is attached to the membrane. The ‘lateral process’ of the manubrium is located at the intersection of the manubrium and the tympanic ring. The ‘U’ labels the umbo, the tip of the handle. The F1, F2 and F3 label black ‘fringes’ related to the zeros in the IR at 0.09, 0.21 and 0.33 micrometers, respectively.