scholarly journals Imaging Through Random Scatterer with Spatial Coherence Structure Measurement

2022 ◽  
Vol 9 ◽  
Author(s):  
Deming Peng ◽  
Xuan Zhang ◽  
Yonglei Liu ◽  
Yimeng Zhu ◽  
Yahong Chen ◽  
...  
Keyword(s):  
Phase Retrieval ◽  
Spatial Coherence ◽  
Three Dimensional ◽  
Retrieval Algorithm ◽  
Scattering Media ◽  
Image Information ◽  
Partially Coherent Light ◽  
Spatial Shape ◽  
Structure Measurement ◽  
Coherent Light Beam

Optical coherence is becoming an efficient degree of freedom for light field manipulations and applications. In this work, we show that the image information hidden a distance behind a random scattering medium is encoded in the complex spatial coherence structure of a partially coherent light beam that generates after the random scatterer. We validate in experiment that the image information can be well recovered with the spatial coherence measurement and the aid of the iterative phase retrieval algorithm in the Fresnel domain. We find not only the spatial shape but also the position including the lateral shift and longitudinal distances of the image hidden behind the random scatterer can be reconstructed, which indicates the potential uses in three-dimensional optical imaging through random scattering media.

scholarly journals Synchrotron-based phase-contrast micro-CT as a tool for understanding pulmonary vascular pathobiology and the 3-D microanatomy of alveolar capillary dysplasia

2020 ◽  
Vol 318 (1) ◽  
pp. L65-L75 ◽  
Author(s):  
Christian Norvik ◽  
Christian Karl Westöö ◽  
Niccolò Peruzzi ◽  
Goran Lovric ◽  
Oscar van der Have ◽  
...  
Keyword(s):  
Phase Contrast ◽  
Phase Retrieval ◽  
Pulmonary Veins ◽  
Three Dimensional ◽  
Surrounding Tissue ◽  
Retrieval Algorithm ◽  
Micro Ct ◽  
Bronchial Arteries ◽  
Alveolar Capillary Dysplasia ◽  
Alveolar Capillary

This study aimed to explore the value of synchrotron-based phase-contrast microcomputed tomography (micro-CT) in pulmonary vascular pathobiology. The microanatomy of the lung is complex with intricate branching patterns. Tissue sections are therefore difficult to interpret. Recruited intrapulmonary bronchopulmonary anastomoses (IBAs) have been described in several forms of pulmonary hypertension, including alveolar capillary dysplasia with misaligned pulmonary veins (ACD/MPV). Here, we examine paraffin-embedded tissue using this nondestructive method for high-resolution three-dimensional imaging. Blocks of healthy and ACD/MPV lung tissue were used. Pulmonary and bronchial arteries in the ACD/MPV block had been preinjected with dye. One section per block was stained, and areas of interest were marked to allow precise beam-alignment during image acquisition at the X02DA TOMCAT beamline (Swiss Light Source). A ×4 magnifying objective coupled to a 20-µm thick scintillating material and a sCMOS detector yielded the best trade-off between spatial resolution and field-of-view. A phase retrieval algorithm was applied and virtual tomographic slices and video clips of the imaged volumes were produced. Dye injections generated a distinct attenuation difference between vessels and surrounding tissue, facilitating segmentation and three-dimensional rendering. Histology and immunohistochemistry post-imaging offered complementary information. IBAs were confirmed in ACD/MPV, and the MPVs were positioned like bronchial veins/venules. We demonstrate the advantages of using synchrotron-based phase-contrast micro-CT for three-dimensional characterization of pulmonary microvascular anatomy in paraffin-embedded tissue. Vascular dye injections add additional value. We confirm intrapulmonary shunting in ACD/MPV and provide support for the hypothesis that MPVs are dilated bronchial veins/venules.

scholarly journals Lensless Three-Dimensional Quantitative Phase Imaging Using Phase Retrieval Algorithm

2020 ◽  
Vol 6 (9) ◽  
pp. 99 ◽  
Author(s):  
Vijayakumar Anand ◽  
Tomas Katkus ◽  
Denver P. Linklater ◽  
Elena P. Ivanova ◽  
Saulius Juodkazis
Keyword(s):  
Phase Retrieval ◽  
Three Dimensional ◽  
Retrieval Algorithm ◽  
Phase Imaging ◽  
Label Free ◽  
Quantitative Phase Imaging ◽  
Single Plane ◽  
Quantitative Phase ◽  
Web Camera ◽  
Phase Retrieval Algorithm

Quantitative phase imaging (QPI) techniques are widely used for the label-free examining of transparent biological samples. QPI techniques can be broadly classified into interference-based and interferenceless methods. The interferometric methods which record the complex amplitude are usually bulky with many optical components and use coherent illumination. The interferenceless approaches which need only the intensity distribution and works using phase retrieval algorithms have gained attention as they require lesser resources, cost, space and can work with incoherent illumination. With rapid developments in computational optical techniques and deep learning, QPI has reached new levels of applications. In this tutorial, we discuss one of the basic optical configurations of a lensless QPI technique based on the phase-retrieval algorithm. Simulative studies on QPI of thin, thick, and greyscale phase objects with assistive pseudo-codes and computational codes in Octave is provided. Binary phase samples with positive and negative resist profiles were fabricated using lithography, and a single plane and two plane phase objects were constructed. Light diffracted from a point object is modulated by phase samples and the corresponding intensity patterns are recorded. The phase retrieval approach is applied for 2D and 3D phase reconstructions. Commented codes in Octave for image acquisition and automation using a web camera in an open source operating system are provided.

scholarly journals Complex Wavefront Shaping through a Multi-Core Fiber

2021 ◽  
Vol 11 (9) ◽  
pp. 3949
Author(s):  
Jiawei Sun ◽  
Nektarios Koukourakis ◽  
Jürgen W. Czarske
Keyword(s):  
Phase Retrieval ◽  
Light Field ◽  
Discrete Distribution ◽  
Cell Manipulation ◽  
Retrieval Algorithm ◽  
Optical Cell ◽  
Loop Control ◽  
Wavefront Shaping ◽  
Core Fiber ◽  
Phase Retrieval Algorithm

Wavefront shaping through a multi-core fiber (MCF) is turning into an attractive method for endoscopic imaging and optical cell-manipulation on a chip. However, the discrete distribution and the low number of cores induce pixelated phase modulation, becoming an obstacle for delivering complex light field distributions through MCFs. We demonstrate a novel phase retrieval algorithm named Core–Gerchberg–Saxton (Core-GS) employing the captured core distribution map to retrieve tailored modulation hologram for the targeted intensity distribution at the distal far-field. Complex light fields are reconstructed through MCFs with high fidelity up to 96.2%. Closed-loop control with experimental feedback denotes the capability of the Core-GS algorithm for precise intensity manipulation of the reconstructed light field. Core-GS provides a robust way for wavefront shaping through MCFs; it facilitates the MCF becoming a vital waveguide in endoscopic and lab-on-a-chip applications.

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