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Lu H, Li Y, Zhang L, Serikawa S. Contrast enhancement for images in turbid water. JOURNAL OF THE OPTICAL SOCIETY OF AMERICA. A, OPTICS, IMAGE SCIENCE, AND VISION 2015; 32:886-893. [PMID: 26366913 DOI: 10.1364/josaa.32.000886] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Absorption, scattering, and color distortion are three major degradation factors in underwater optical imaging. Light rays are absorbed while passing through water, and absorption rates depend on the wavelength of the light. Scattering is caused by large suspended particles, which are always observed in an underwater environment. Color distortion occurs because the attenuation ratio is inversely proportional to the wavelength of light when light passes through a unit length in water. Consequently, underwater images are dark, low contrast, and dominated by a bluish tone. In this paper, we propose a novel underwater imaging model that compensates for the attenuation discrepancy along the propagation path. In addition, we develop a robust color lines-based ambient light estimator and a locally adaptive filtering algorithm for enhancing underwater images in shallow oceans. Furthermore, we propose a spectral characteristic-based color correction algorithm to recover the distorted color. The enhanced images have a reasonable noise level after the illumination compensation in the dark regions, and demonstrate an improved global contrast by which the finest details and edges are enhanced significantly.
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Grabtchak S, Montgomery LG, Pang B, Wang Y, Zhang C, Li Z, Xia Y, Whelan WM. Interstitial diffuse radiance spectroscopy of gold nanocages and nanorods in bulk muscle tissues. Int J Nanomedicine 2015; 10:1307-20. [PMID: 25709450 PMCID: PMC4335609 DOI: 10.2147/ijn.s79246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Radiance spectroscopy was applied to the interstitial detection of localized inclusions containing Au nanocages or nanorods with various concentrations embedded in porcine muscle phantoms. The radiance was quantified using a perturbation approach, which enabled the separation of contributions from the porcine phantom and the localized inclusion, with the inclusion serving as a perturbation probe of photon distributions in the turbid medium. Positioning the inclusion at various places in the phantom allowed for tracking of photons that originated from a light source, passed through the inclusion's location, and reached a detector. The inclusions with high extinction coefficients were able to absorb nearly all photons in the range of 650-900 nm, leading to a spectrally flat radiance signal. This signal could be converted to the relative density of photons incident on the inclusion. Finally, the experimentally measured quantities were expressed via the relative perturbation and arranged into the classical Beer-Lambert law that allowed one to extract the extinction coefficients of various types of Au nanoparticles in both the transmission and back reflection geometries. It was shown that the spatial variation of perturbation could be described as 1/r dependence, where r is the distance between the inclusion and the detector. Due to a larger absorption cross section, Au nanocages produced greater perturbations than Au nanorods of equal particle concentration, indicating a better suitability of Au nanocages as contrast agents for optical measurements in turbid media. Individual measurements from different inclusions were combined into detectability maps.
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Affiliation(s)
- Serge Grabtchak
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI, Canada
- Departments of Electrical and Computer Engineering, and Physics, Dalhousie University, Halifax, Canada
| | - Logan G Montgomery
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI, Canada
| | - Bo Pang
- Department of Biomedical Engineering, Peking University, Beijing, People’s Republic of China
- The Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Yi Wang
- The Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- Key Laboratory of Green Synthesis and Applications, College of Chemistry, Chongqing Normal University, Chongqing, People’s Republic of China
| | - Chao Zhang
- Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, People’s Republic of China
- College of Physics and Optoelectronics, South China University of Technology, Guangzhou, People’s Republic of China
| | - Zhiyuan Li
- Laboratory of Optical Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, People’s Republic of China
- College of Physics and Optoelectronics, South China University of Technology, Guangzhou, People’s Republic of China
| | - Younan Xia
- The Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
- School of Chemistry and Biochemistry, and School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - William M Whelan
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI, Canada
- Atlantic Veterinary College, Charlottetown, PEI, Canada
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Grabtchak S, Callaghan KB, Whelan WM. Tagging photons with gold nanoparticles as localized absorbers in optical measurements in turbid media. BIOMEDICAL OPTICS EXPRESS 2013; 4:2989-3006. [PMID: 24409396 PMCID: PMC3862156 DOI: 10.1364/boe.4.002989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 11/19/2013] [Accepted: 11/21/2013] [Indexed: 06/03/2023]
Abstract
We analyze a role of a localized inclusion as a probe for spatial distributions of migrating photons in turbid media. We present new experimental data and two-dimensional analysis of radiance detection of a localized absorptive inclusion formed by gold nanoparticles in Intralipid-1% when the target is translated along the line connecting the light source and detector. Data are analyzed using the novel analytical expression for the relative angular photon distribution function for radiance developed by extending the perturbation approach for fluence. Obtained photon maps allow predicting conditions for detectability of inclusions for which proximity to the detector is essential.
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Affiliation(s)
- Serge Grabtchak
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI C1A4P3, Canada
- Departments of Electrical and Computer Engineering, and Physics, Dalhousie University, Halifax, NS B3H3J5, Canada
| | - Kristen B. Callaghan
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI C1A4P3, Canada
| | - William M. Whelan
- Department of Physics, University of Prince Edward Island, Charlottetown, PEI C1A4P3, Canada
- Atlantic Veterinary College, Charlottetown, PEI C1A4P3, Canada
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