Combined two nonlinear image processings for speckle-free imaging with the optical array imaging system

Abstract

In previous articles an optical array imaging system has been presented, where after collecting the array data the eigenvector with the largest eigenvalue is derived and it is computationally beamsteared to get images of the object. Images obtainable with this system have serious speckle noise. Two nonlinear processing methods are applied to reduce the speckle noise. One method is to average the intensity images over the parameter of the array elements used for laser light transmission. The other is to apply a Gaussian low-pass filter to the averaged image after taking its logarithm. Their usefulness was examined by computer simulation and it was shown that almost speckle-free imaging is achievable with little effects on image resolution.