Deep speckle correlation: a deep learning approach toward scalable imaging through scattering media

Author(s):

Yunzhe Li and Yujia Xue and Lei Tian

Abstract:

“Imaging through scattering is an important yet challenging problem. Tremendous progress has been made by exploiting the deterministic input–output “transmission matrix” for a fixed medium. However, this “one-to-one” mapping is highly susceptible to speckle decorrelations – small perturbations to the scattering medium lead to model errors and severe degradation of the imaging performance. Our goal here is to develop a new framework that is highly scalable to both medium perturbations and measurement requirement. To do so, we propose a statistical “one-to-all” deep learning (DL) technique that encapsulates a wide range of statistical variations for the model to be resilient to speckle decorrelations. Specifically, we develop a convolutional neural network (CNN) that is able to learn the statistical information contained in the speckle intensity patterns captured on a set of diffusers having the same macroscopic parameter. We then show for the first time, to the best of our knowledge, that the trained CNN is able to generalize and make high-quality object predictions through an entirely different set of diffusers of the same class. Our work paves the way to a highly scalable DL approach for imaging through scattering media.”

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Publication: Optica

Issue/Year/DOI: Optica Volume 5, Issue 10 pp. 1181-1190 (2018)
DOI: 10.1364/OPTICA.5.001181

Single-shot memory-effect video

Author(s):

Xiaohan Li and Andrew Stevens and Joel A. Greenberg and Michael E. Gehm

Abstract:

“Imaging through opaque scattering media is critically important in applications ranging from biological and astronomical imaging to metrology and security. While the random process of scattering in turbid media produces scattered light that appears uninformative to the human eye, a wealth of information is contained in the signal and can be recovered using computational post-processing techniques. Recent studies have shown that statistical correlations present in the scattered light, known as ‘memory effects’, allow for diffraction-limited imaging through opaque media without detailed knowledge of (or access to) the source or scatterer. However, previous methods require that the object and/or scatterer be static during the measurement. We overcome this limitation by combining traditional memory effect imaging with coded-aperture-based computational imaging techniques, which enables us to realize for the first time single-shot video of arbitrary dynamic scenes through dynamic, opaque media. This has important implications for a wide range of real-world imaging scenarios.”

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Publication: Scientific Reports

Issue/Year/DOI: Scientific Reports 8, Article number: 13402 (2018)
DOI: 10.1038/s41598-018-31697-8

Generation of focal pattern with controllable polarization and intensity for laser beam passing through a multi-mode fiber

Author(s):

Weiru Fan and Xiansheng Hu and Bamao Zhaxi and Ziyang Chen and Jixiong Pu

Abstract:

“Similar to coherent light passing through a scattering medium, the propagation of coherent light through a multi-mode fiber (MMF) will result in a random speckle field. For a non-polarization maintaining MMF, the randomization can be observed not only in the intensity distribution, but also in the polarization state. In this paper, we propose a new technique known as phase combination to control the optical field for the light passing through the MMF. We show that, based on this new technique, the random speckle pattern can be modulated into an intensity distribution of two bright focal spots with mutually perpendicular polarization by only one polarizer. In particular, the intensity distribution of these two focal spots can be quantitatively controlled. This technique may find applications in medical imaging, nonlinear optics and optical communication etc.”

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Publication: Optics Expresss

Issue/Year/DOI: Optics Express Volume 26, Issues 6 pp. 7693-7700 (2018)
DOI: 10.1364/OE.26.007693

Imaging moving targets through scattering media

Author(s):

Michelle Cua and Edward (Haojiang) Zhou and Changhuei Yang

Abstract:

“Optical microscopy in complex, inhomogeneous media is challenging due to the presence of multiply scattered light that limits the depths at which diffraction-limited resolution can be achieved. One way to circumvent the degradation in resolution is to use speckle- correlation-based imaging (SCI) techniques, which permit imaging of objects inside scattering media at diffraction-limited resolution. However, SCI methods are currently limited to imaging sparsely tagged objects in a dark-field scenario. In this work, we demonstrate the ability to image hidden, moving objects in a bright-field scenario. By using a deterministic phase modulator to generate a spatially incoherent light source, the background contribution can be kept constant between acquisitions and subtracted out. In this way, the signal arising from the object can be isolated, and the object can be reconstructed with high fidelity. With the ability to effectively isolate the object signal, our work is not limited to imaging bright objects in the dark-field case, but also works in bright-field scenarios, with non-emitting objects.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express Vol. 25, Issue 4, pp. 3935-3945  (2017)

DOI: 10.1364/OE.25.003935

 

Focusing light into desired patterns through turbid media by feedback-based wavefront shaping

Author(s):

Lipeng Wan and Ziyang Chen and Huiling Huang and Jixiong Pu

Abstract:

“We demonstrate that the focusing of light into
desired patterns through turbid media can be realized using
feedback-based wavefront shaping. Three desired focused
patterns—a triangle, a circle, and a rectangle—are used as
examples to study this ability. During the process of modulating
scattered light, the Pearson’s correlation coefficient is
introduced as a feedback signal. It is found that the speckle
field formed by the turbid media gradually transforms into
the desired pattern through a process of modulation of the
input beam wave front. The proposed approach has potential
applications in biomedical treatment and laser material
processing.”

Link to Publications Page

Publication: Applied Physics B

Issue/Year/DOI: Applied Physics B 122:204
DOI: 10.1007/s00340-016-6466-0