Quasi noise-free digital holography

Abstract

One of the main drawbacks of Digital Holography (DH) is the coherent nature of the light source, which severely corrupts the quality of holographic reconstructions. Although numerous techniques to reduce noise in DH have provided good results, holographic noise suppression remains a challenging task. We propose a novel framework that combines the concepts of encoding multiple uncorrelated digital holograms, block grouping and collaborative filtering to achieve quasi noise-free DH reconstructions. The optimized joint action of these different image-denoising methods permits the removal of up to 98% of the noise while preserving the image contrast. The resulting quality of the hologram reconstructions is comparable to the quality achievable with non-coherent techniques and far beyond the current state of art in DH. Experimental validation is provided for both single-wavelength and multi-wavelength DH, and a comparison with the most used holographic denoising methods is performed.

An Improved Image Denoising Model Based on Nonlocal Means Filter

“…which is the discrete version of (22). To find a minimizer , the following heat equation is considered in [43] = Δ − ( − )…”

“…This is an inverse problem, and in general there is no solution. Nevertheless, there are many useful methods to deal with this problem, for example, the median filter, the Wiener filter, the bilateral filter, variational methods [1][2][3][4][5], sparse representation based methods [6], wavelet-based methods [7], the convolutional neural network based methods [8][9][10], nonlocal self-similarity based methods [11][12][13][14][15][16][17][18][19][20], and collaborative filtering methods [12][13][14][15][21][22][23].…”

“…K. Dabov et al [15] proposed the sparse 3D transform-domain collaborative filtering (BM3D) method, in which one exploits the inherent nonlocal self-similarity property of natural images, groups similar 2D image fragments into 3D groups, and then deals with these 3D groups by the developed collaborative filtering procedure. The BM3D and its variants proposed in [15,[21][22][23][24][25][26] have been demonstrated to achieve state-of-the-art performance. In [21,22], the BM3D is applied for coherent noise reduction in digital holography.…”

“…The BM3D and its variants proposed in [15,[21][22][23][24][25][26] have been demonstrated to achieve state-of-the-art performance. In [21,22], the BM3D is applied for coherent noise reduction in digital holography. In [23], an iterative algorithm combining BM3D technique was proposed for the salt and paper (S&P) noise removal.…”

Ultra-high speed digital micro-mirror device based ptychographic iterative engine method

“…Quantitative phase imaging techniques can measure the accurate complex amplitude of the light field including the modulus and phase simultaneously and thus are more suitable for the quantitative analysis. In digital holography and other interference based imaging methods, the regular reference beam adopted always makes the setup complicated and sensitive to the outside disturbance [3][4][5]. Transport of intensity equation (TIE) method, which is a non-interference phase imaging technique, has much simpler setup and lower requirement on the working environment [6][7][8][9][10][11][12][13], and recently developed Fourier ptychographic microscopy [14,15] is another non-interference phase imaging technique that can provide complex amplitude of sample, however like other lens aided imaging methods, the accuracy of these two techniques is dependent to the used optics.…”