Automatic Reconstruction of Positive First-Order Image by Off-Axis Digital Holography
Aiming at the problem of blurring reconstruction of zero-level and conjugate images in off-axis digital holography,a method based on the peak signal-to-noise ratio is proposed to automatically extract the positive first-order spectrum and reconstruct its image.The rationality and feasibility of the method are theoretically deduced and analyzed,and the three impulse function points of the spectral amplitude corresponding to the centers of the positive and negative first-order and zero-order spectrum are known.The three centers can be determined by the amplitude maxima in the spectrogram,then the positive first-order spectrum is extracted by using a circular filter window,and the peak signal-to-noise ratio is used as an objective evaluation basis to determine the optimal radius of filter window and reconstruction distance.The experimental results show that the proposed method can automatically reconstruct the positive first-order image of the out-of-focus hologram,and its peak signal-to-noise ratio is improved by 32.2％compared with the unfiltered reconstruction results,and by 7.6％compared with the global thresholding step-by-step iterative method.The method does not depend on other a priori information and provides a new feasible scheme for off-axis holographic spectral filtering algorithms.
off-axis digital holographypositive first-order spectrumpeak signal-to-noise ratioradius of filter windowout-of-focus images
万方数据
维普
