Interference suppression in digital holographic images

This paper presents a digital filtering software module for noise suppression in reconstructed holographic images and in original digital holograms. In the core of the developed module is a direct two-dimensional Fourier transform applied to the holographic image. In the obtained Fourier image of the hologram, the algorithm determines pixels carrying information about interference with white color brightness (grayscale palette) below a certain threshold (in our case, based on experimental results, a threshold of 50 was chosen). Then, using an averaging operator, the brightness of such pixels is brought to the brightness value of the surrounding pixels, creating a blurring effect. After filtering, an inverse two-dimensional Fourier transform is applied to obtain a noise-free digital filtered image of the coordinate plane. Based on the results of processing of numerous digital holograms, it is revealed that the developed module can remove interference without loss of information about the shape and location of the registered objects.