• Chinese Optics Letters
  • Vol. 21, Issue 10, 101102 (2023)
Riffat Tehseen1, Amjad Ali1, Mithilesh Mane1, Wenmin Ge1, Yanlong Li1, Zejun Zhang1、2、3, and Jing Xu1、2、3、*
Author Affiliations
  • 1Optical Communication Laboratory, Ocean College, Zhejiang University, Zhoushan 316021, China
  • 2Hainan Institute of Zhejiang University, Sanya 572000, China
  • 3Key Laboratory of Ocean Observation-Imaging Testbed of Zhejiang Province, Ocean College, Zhejiang University, Zhoushan 316021, China
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    DOI: 10.3788/COL202321.101102 Cite this Article Set citation alerts
    Riffat Tehseen, Amjad Ali, Mithilesh Mane, Wenmin Ge, Yanlong Li, Zejun Zhang, Jing Xu. Enhanced imaging through turbid water based on quadrature lock-in discrimination and retinex aided by adaptive gamma function for illumination correction[J]. Chinese Optics Letters, 2023, 21(10): 101102 Copy Citation Text show less

    Abstract

    This paper presents an improved method for imaging in turbid water by using the individual strengths of the quadrature lock-in discrimination (QLD) method and the retinex method. At first, the high-speed QLD is performed on images, aiming at capturing the ballistic photons. Then, we perform the retinex image enhancement on the QLD-processed images to enhance the contrast of the image. Next, the effect of uneven illumination is suppressed by using the bilateral gamma function for adaptive illumination correction. The experimental results depict that the proposed approach achieves better enhancement than the existing approaches, even in a high-turbidity environment.
    I=ImM×L×[01010101]1×LT,

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    Q=ImM×L×[10101010]1×LT,

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    IQLD(x,y)=IL(x,y)×R(x,y),

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    ILi(x,y)=IQLD(x,y)*Gi(x,y),

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    Gi(x,y)=12πσi2exp(x2y22σi2),

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    rMSR(x,y)=i=1nwi{log[IQLD(x,y)]log[ILi(x,y)]},

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    Oh(x,y)=[255·(RMSR(x,y)255)]γ,

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    Ol(x,y)=255·[1(255RMSR(x,y)255)]γ,γ=γ0|μIL(x,y)|μ,

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    Iadpt(x,y)=α·Oh(x,y)+(1α)·Ol(x,y),α={1,IL(x,y)μ,0,IL(x,y)>μ,

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    Ic(x,y)=RMSR(x,y)×ILc(x,y).

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    Iout(x,y)=β·Ic(x,y)+(1β)·Iadpt(x,y).

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    Riffat Tehseen, Amjad Ali, Mithilesh Mane, Wenmin Ge, Yanlong Li, Zejun Zhang, Jing Xu. Enhanced imaging through turbid water based on quadrature lock-in discrimination and retinex aided by adaptive gamma function for illumination correction[J]. Chinese Optics Letters, 2023, 21(10): 101102
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