Patent ID: 8237933

Claim:
An apparatus for image acquiring, comprising: a light beam generator, capable of generating a light beam; a beam splitting unit, capable of reflecting the light beam to generate a reflected light beam; an interferoscope set, capable of transforming the reflected light beam into a reference light beam and a measurement light beam incident on an object to be tested and reflected to the interferoscope set so as to combine with the reference light beam to form an interfered light beam emitted into the beam splitting unit; and an image acquiring unit coupled to a first actuator on one side, capable of receiving the interfered light beam from the beam splitting unit so as to form an image, obtaining a peak of the sharpness focusing index curve and a peak of the contract focusing index curve, and performing a calibration process to calibrate a relative position of the peak of the sharpness focusing index curve to the peak of the contrast focusing index curve so as to obtain a sequence of clear interference images.