Noise suppression of the reconstruction of infrared digital holography based on pyramid-based bilateral filter

In this paper, we present a new technique of speckle noise suppressing of infrared digital hologram. This technique uses the Laplacian pyramid to separate the original reconstructed hologram into different layers, and conducts the bilateral filter onto each layer to discriminate the noise and the detail information. Because not all noise can be discriminated by the bilateral filter, we design an improved median filter to filter the leftover noise. The detail information of each pyramid layer can then be enhanced without too much noise. We retrieve the separated layer back to a reconstructed image using the reverse Laplacian pyramid method. This technique works effectively on the infrared digital holograms in noise suppressing. No multiple holograms or specific mechanical equipment are needed for doing so, which makes this technique easy to calculate and realize. Figures and numerical results are shown in this paper to demonstrate the performance of this technique.