Automatic filtering processing in off-axis digital holography with clustering algorithm

In this paper, automatic filtering for amplitude and phase reconstruction in off-axis digital holography is developed. A user-friendly interface for automatic filtering is given via program design with MATLAB. The hologram to be processed is input at the front end, and automatic spectrum filtering in Fourier spectrum domain of digital holograms is realized by using clustering algorithm at the back end. The amplitude and phase images are reconstructed from the intercepted spatial-frequency spectrum by using the reconstruction algorithm. This automatic filtering program has high robustness, which can achieve reconstruction imaging for off-axis holograms correctly and effectively in the case of different off-axis angles or different image sizes. For the user interface, upon inputting an off-axis digital hologram and confirming the operation, the reconstructed amplitude and phase images can be quickly output. This user interface has the advantages of simple operation, adjustable parameters and clear feedback. Since K-means clustering is used, this filtering algorithm increases the efficiency in processing experimental data and the reliability of reconstruction imaging. The digital hologram computer-generated is used to simulate filtering processing. The results show that the quality of reconstructed images by using the presented automatic filtering is not inferior to that by conventional manual filtering.