A new approach for signal loss compensation in a vibrometer

This paper presents an approach for signal loss compensation in vibrometry, a contactless measurement technique. Since a new scanning method based on computer generated holograms was developed, now signal loss caused by speckle effects can be reduced and in the best case significantly compensated. For this, multiple Zernike polynomials are used in a Zernike expansion mapped to a computer generated hologram, which modifies the wave front of a coherent laser beam. The coefficients of each Zernike polynomial are used as parameters in a global optimization. Solving this optimization problem with a suitable cost function leads to an increased signal level.