Optical deformation measuring apparatus by double-writing speckle images into a spatial light modulator

An apparatus for measuring a deformation of an object, comprising:

• a light source for illuminating the object;
• input means for forming an input optical image based on reflected or transmitted light from the object;
• a first spatial light modulator for storing by double writing the input optical images of the object before and after the deformation thereof in the form of a double-written image;
• a first read optical system for introducing first read light for reading out the double-written image from the first spatial light modulator;
• a first Fourier transform optical system for Fourier-transforming a first output optical image read out from the first spatial light modulator;
• a second spatial light modulator for storing the first Fourier-transformed image;
• a second read optical system for introducing second read light for reading out the stored first Fourier-transformed image from the second spatial light modulator;
• a second Fourier transform optical system for Fourier-transforming a second output optical image read out from the second spatial light modulator;
• and
• observing means for measuring the second Fourier-transformed image to determine the deformation of the object.

An apparatus for measuring a deformation of an object, comprising:

• a light source for illuminating the object;
• first input means for forming a first input optical image based on reflected or transmitted light from the object before the deformation thereof;
• a first spatial light modulator for storing the first input image;
• second input means for forming a second input optical image based on reflected or transmitted light from the object after the deformation thereof;
• a second spatial light modulator for storing the second input image;
• a read optical system for introducing read coherent light for reading out the first input image from the first spatial light modulator;
• optical means for introducing the read coherent light reflected or transmitted from the first spatial light modulator to an output surface of the second spatial light modulator to produce an output optical image which has been subjected to an exclusive-OR operation between the first and second input images;
• a Fourier transform optical system for Fourier-transforming the output optical image;
• and
• observing means for measuring the Fourier-transformed image to determine the deformation of the object.