en
×

分享给微信好友或者朋友圈

使用微信“扫一扫”功能。
作者简介:

李浩翔(1993-),男,博士生,主要从事水下偏振去散射研究。

通讯作者:

朱京平(1967-),女,博士,教授,主要从事偏振光谱成像与水下偏振探测研究。

中图分类号:TP391.4

文献标识码:A

文章编号:2096-5753(2023)04-0435-07

DOI:10.19838/j.issn.2096-5753.2023.04.006

参考文献 1
JAFFE J S.Underwater optical imaging:the past,the present,and the prospects[J].IEEE Journal of Oceanic Engineering,2015,40(3):683-700.
参考文献 2
LIU F,HAN P L,WEI Y,et al.Deeply seeing through highly turbid water by active polarization imaging[J].Optics Letters,2018,43(20):4903-4906.
参考文献 3
TREIBITZ T,SCHECHNER Y Y.Active polarization descattering[J].IEEE Transactions on Pattern Analysis and Machine Intelligence,2009,31(3):385-399.
参考文献 4
SCHETTINI R,CORCHS S.Underwater image processing:state of the art of restoration and image enhancement methods[J].EURASIP Journal on Advances in Signal Processing,2010,1:746052.
参考文献 5
CHIANG J Y,CHEN Y C.Underwater image enhancement by wavelength compensation and dehazing[J].IEEE Transactions on Image Processing,2012,21(4):1756-1769.
参考文献 6
LI X B,HAN Y L,WANG H Y,et al.Polarimetric imaging through scattering media:a review[J].Frontiers in Physics,2022,10:3389.
参考文献 7
HE K M,SUN J,TANG X O.Single image haze removal using dark channel prior[J].IEEE Transactions on Pattern Analysis and Machine Intelligence,2011,33(12):2341-2353.
参考文献 8
AMER K O,ELBOUZ M,ALFALOU A,et al.Enhancing underwater optical imaging by using a low-pass polarization filter[J].Optics Express,2019,27(2):621-643.
参考文献 9
TANG A P.A restoration of underwater polarized images based on DCP[C]//2019 International Conference on Sensing,Diagnostics,Prognostics,and Control(SDPC).Beijing:IEEE,2019.
参考文献 10
CHEN X W,JIN M Y,CHEN H L,et al.Computational temporal ghost imaging for long-distance underwater wireless optical communication[J].Optics Letters,2021,46(8):1938-1941.
参考文献 11
SCHECHNER Y Y,KARPEL N.Recovery of underwater visibility and structure by polarization analysis [J].IEEE Journal of Oceanic Engineering,2005,30(3):570-587.
参考文献 12
LI X B,XU J N,ZHANG L P,et al.Underwater image restoration via Stokes decomposition[J].Optics Letters,2022,47(11):2854-2857.
参考文献 13
HU H F,ZHANG Y B,LI X B,et al.Polarimetric underwater image recovery via deep learning[J].Optics and Lasers in Engineering,2020,133:106152.
参考文献 14
REN Q M,XIANG Y F,WANG G C,et al.The underwater polarization dehazing imaging with a lightweight convolutional neural network[J].Optik,2022,251:168381.
参考文献 15
HU H F,HAN Y L,LI X B,et al.Physics-informed neural network for polarimetric underwater imaging[J].Optics Express,2022,30(13):22512-22522.
参考文献 16
HU H F,ZHAO L,LI X B,et al.Underwater image recovery under the nonuniform optical field based on polarimetric imaging[J].IEEE Photonics Journal,2018,10(1):1-9.
参考文献 17
HU H F,ZHAO L,HUANG B J,et al.Enhancing visibility of polarimetric underwater image by transmittance correction[J].IEEE Photonics Journal,2017,9(3):1-10.
参考文献 18
HUANG B J,LIU T G,HU H F,et al.Underwater image recovery considering polarization effects of objects[J].Optics Express,2016,24(9):9826-9838.
参考文献 19
JIN L L,HONG L.Deep learning for underwater image recognition in small sample size situations[C]//Oceans 2017.Aberdeen:IEEE,2017.
参考文献 20
HAN P L,LIU F,WEI Y,et al.Optical correlation assists to enhance underwater polarization imagingperformance[J].Optics and Lasers in Engineering,2020,134:106256.
参考文献 21
DUBREUIL M,DELROT P,LEONARD I,et al.Exploring underwater target detection by imaging polarimetry and correlation techniques[J].Applied Optics,2013,52(5):997-1005.
参考文献 22
ZHANG H J,REN M Y,WANG H T,et al.Fast processing of underwater polarization imaging based on optical correlation[J].Applied Optics,2021,60(15):4462-4468.
参考文献 23
GUAN J G,ZHAO Y,ZHENG Y Q,et al.Optical polarization imaging for underwater target detection with non-scatter background[J].Journal of Measurement Science & Instrumentation,2020,11(4):335-342.
参考文献 24
HU H F,LI J Q,LI X B,et al.Underwater polarization difference imaging with three degrees of freedom[J].Acta Optica Sinica,2021,41(3):0329001.
参考文献 25
YANG S L,QU B W W,LIU G S,et al.Unsupervised learning polarimetric underwater image recovery under nonuniform optical fields[J].Applied Optics,2021,60(26):8198-8205.
参考文献 26
YU T,WANG X L,XI S X,et al.Underwaterpolarization imaging for visibility enhancement of moving targets in turbid environments[J].Optics Express,2023,31(1):459-468.
参考文献 27
ZHAO Y Z,HE W J,REN H,et al.Polarization descattering imaging through turbid water without prior knowledge[J].Optics and Lasers in Engineering,2022,148(23-24):106777.
参考文献 28
LIANG J,JU H J,REN L Y,et al.Generalized polarimetric dehazing method based on low-pass filtering in frequency domain[J].Sensors,2020,20(6):1729.
参考文献 29
TIAN H,ZHU J P,TAN S W,et al.Rapid underwater target enhancement method based on polarimetric imaging[J].Optics & Laser Technology,2018,108:515-520.
参考文献 30
PANETTA K A,WHARTON E J,AGAIAN S S.Human visual system-based image enhancement and logarithmic contrast measure[J].IEEE Transactions on Systems,Man,and Cybernetics.Part B:Cybernetics,2008,38(1):174-188.
目录contents

    摘要

    受浑浊水体自身吸收与微颗粒散射的影响,水下光学成像面临成像距离短、像质差等问题。一种基于斯托克斯参量的主动偏振成像模型被应用到水下成像去散射过程中,有效提升了目标成像探测的清晰度。相比于被动偏振成像模型,引入主动光源可以实现对入射光的偏振调制,由此可以充分挖掘目标反射光与介质光的偏振特征差异进而实现分离选通。改进的主动偏振去散射模型利用了目标反射光的偏振共模抑制效应,借助偏振斯托克斯参量 S2 分量实现了介质光偏振角与偏振度全局分布的准确估算。同时引入图像质量评价参数对比度 contrast 作为反馈参量,通过迭代计算实现背景噪声的最大化滤除。不同散射程度、不同类型目标的水下成像实验表明:相比于传统主动偏振成像方法,改进后的成像模型可大幅提升水下目标的图像质量,特别是强散射环境下的图像 contrast 提升超 2 倍以上。该项工作为利用偏振信息进行水下图像去散射与目标重建提供了新思路。

    Abstract

    Affected by absorption of turbid water and scattering of micro-particles,underwater optical imaging faces the problems of short imaging distance and poor image quality. In this paper,an improved active polarization imaging method is introduced into the descattering process to achieve higher imaging contrast. Compared with the passive polarization imaging model,the introduction of an active light source can perform polarization modulation on the incident light,which better serves the underwater optical transmission model to separate and solve the target information. For the first time,the S2 component of Stokes vectors based on the common mode suppression is used to eliminate the interference of the target information. Therefore,the polarization degree of backscattered light is accurately reconstructed. Meanwhile,introducing contrast as feedback optimization is to achieve determination of optimal parameters. The imaging experiments with different types of targets prove the effectiveness of the method under various turbidities water. The imaging contrast is improved by more than 2 times in strong scattering water. This work provides a new idea for introducing the polarization information into the enhancement and restoration of the target information.

  • 0 引言

  • 水下成像在海洋工程和科学研究中发挥着举足轻重的作用,而光学成像技术因灵敏度高、成像速度快、空间分辨率高等独特优势在海洋科考、水下救援、海底资源勘探、水下重点目标监测等领域具有重要的应用前景[1-3]。然而受浑浊水体自身的吸收作用影响,成像作用距离大大降低。受水体不同种类微悬浮物的强散射作用,成像对比度大幅下降,目标信息淹没在背景噪声中[4-6]。为克服水下强散射影响,近年来基于暗通道去散射的水下成像技术[7-9],基于量子关联效应的鬼成像技术[10]、基于水下光传输物理模型的复原技术[11-12]、基于深度学习的图像重构技术[13-15]都大幅提升了水下成像的质量。而偏振成像技术因设备简便、无先验信息、成像质量佳,在水下目标探测中也表现出良好的应用潜力。

  • SCHECHNER 和 KARPEL 在 2005 年提出水下清晰化成像模型[11],其以水体透射系数的估计为重点,建立被动照射下目标信息复原的方法。针对原模型中理想假设,近年来研究者针对无穷远处介质光分布拟合[16]、水体透射函数校正[17]、目标本身偏振差分信息估算[18]、水体对不同波段选择性吸收[19]影响等一系列问题进行了改进与完善,进一步证明了偏振成像技术可行性。由于引入主动光源可以克服水体吸收的影响,同时对入射偏振信号进行调制,SCHECHNER 与 TREIBITZ 在 2009 年提出了浑浊水体中主动偏振成像模型,在考虑目标的偏振特性同时,进一步提升成像对比度与清晰度[3]。之后,光学相关性被用来估计高浊度水中物体的退偏程度[20-21],以及最优正交图像的选取[22];2020 年管今哥等人以水下主动偏振成像模型为基础针对无散射参照的水下场景提出了偏振减法成像[23]; 2021 年胡浩峰团队提出了一种三自由度计算偏振差分成像去散射方法[24],获得更好的复原结果。为了适应不同成像场景,近期多项研究针对非均匀光照[25],目标移动[26],无背景参照[27]等开展了研究,进一步拓展了水下偏振成像的应用范围。在主动偏振去散射过程中,对于目标信息与介质信息的偏振度的估算是极其关键过程,其直接影响去散射的效果。之前的研究通常将无目标区域作为抽样去获得固定的偏振度数值,而实际成像过程中,受光源非均匀性影响,全场景偏振度分布差异极大,人为随机抽样取值将带来更大的复原误差。

  • 本文基于反射型偏振目标在主动偏振分离选通成像时介质信息与目标信息的偏振特征差异,突破以往采用最亮与最暗正交子图像进行目标重建时介质光偏振度分布估算不准确的问题,首次借助偏振斯托克斯参量中的 S2分量实现偏振共模抑制,减少了目标漫射光的干扰,准确还原了介质光的偏振角与偏振度分布。不同散射场景下的成像实验表明:该方法在充分复原目标信息的同时,实现了对介质光的分离滤除,即使在强散射环境下效果仍然良好。本研究为水下主动偏振成像模型关键参量计算提供了全新的思路,进一步提升了偏振成像在强散射环境下的成像稳定性。

  • 1 水下目标主动偏振去散射模型

  • 为了提高浑浊介质中目标的成像效果,TREIBITZ 根据介质光和目标光的偏振特性差异提出了一种单独提取目标光信息的去散射物理模型[3]。模型的具体原理:探测器接收到的光包括目标光和介质光 2 部分,即

  • I=B+D
    (1)
  • 式中:I 为进入探测器的总光强;B 为进入探测器的介质光; D 为进入探测器的目标光。

  • 任何偏振状态的光均可以被分解到 2 个相互正交的方向上,因此进入探测器的总光强、介质光以及目标光可分别表示为

  • I=Ico+Icr
    (2)
  • B=Bco+Bcr
    (3)
  • D=Dco+Dcr
    (4)
  • 式中:co 代表平行方向;cr 代表垂直方向。

  • 进入探测器的所有光强中与入射光振动方向相同以及与入射光振动方向正交的光强可分别表示为

  • Ico=Bco+Dco
    (5)
  • Icr=Bcr+Dcr
    (6)
  • 根据偏振度的定义可以分别得到介质光和目标光的偏振度:

  • PB=Bco-BcrBco+Bcr
    (7)
  • PT=Dco-DcrDco+Dcr
    (8)
  • 式中: PB 为介质光偏振度; PT 为目标光偏振度。

  • 根据上面公式可推导出目标光的表达式:

  • D=1PB-PTIcr1+PB-Ico1-PB
    (9)
  • 2 基于斯托克斯参量的主动去散射模型

  • 2.1 目标信息的复原求解

  • 在之前的研究中关于介质光偏振度的确定主要采用无目标区域进行抽样确定,该过程存在一定的误差,这里引入托克斯参量 S2,由于目标光反射光的偏振特性,当入射偏振方向为 0°时,其在 45° 方向与 135°方向分解后差值为 0,即:

  • Dpd=D45-D135=0
    (10)
  • 使用 S2 参量可以避免目标漫射光的干扰,其偏振度可以表示为

  • PB=S2S01sin2θ=B45-B135B45+B1351sin2θ
    (11)
  • 介质光的偏振角可以表示为

  • θ=12arctanS2(B)S1(B)
    (12)
  • 由于 S2 分量中不包含目标信息,所以介质光的 S2 分量:

  • S2(B)=S2(I)=I45-I135
    (13)
  • 对于介质光的 S1 分量:

  • S1(B)=S1(I)-S1(D)
    (14)
  • 这里需要确定目标光的偏振差分信息,我们借鉴了文献[18]中方法,构建了 Kxy),如下:

  • K(x,y)=Ico(x,y)Aco-Icr(x,y)Acr
    (15)
  • 式中,AcoAcr分别代表了与入射偏振态平行与垂直时检偏图像背景区域无穷远处介质光强度。

  • 进一步将目标的偏振差分信息表示为

  • S1(D)=nexp[mK(x,y)]
    (16)
  • 式中,(mn)为调节系数,其确定方法在之前研究中已有说明[18]

  • 由此将方程(16),(11),(12),(13)联立即可获得介质光偏振度分布,进一步代入式(9)即可获得最终的目标信息 D

  • D=1KS2S1-PTIcr1+KS2S1-Ico1-KS2S1
    (17)
  • 这里目标信息的偏振度由于是反射型偏振目标,所以取 PT1。

  • 2.2 最优目标图像的获取

  • 为了获得最好的去散射效果,我们引入对比度 contrast 参数作为一种反馈,通过 MATLAB 计算程序进行逐步迭代运算。具体过程如下:以 0.01 为步长的值,逐步迭代计算(mn)所对应的图像质量参数,寻找 contrast[28]评价参数同时最大时所对应系数值。

  • contrast =σI-=1M×Ni=1M j=1N [I(i,j)-I-]21M×Ni=1M j=1N I(i,j)
    (18)
  • optical (m,n)=max( contrast )
    (19)
  • 式中: Iij)为输入的图像;I-为图像所有像素的灰度均值;MN 分别代表了图像像素的行列数。

  • 3 实验与结果

  • 3.1 实验设置

  • 通过图1 所示的实验装置我们获得了浑浊水体中不同场景下的偏振图像。实验中采用的光源是中心波长为 532 nm 的发光二极管(THORLABS M532L3)。入射光通过偏振态发生器(PSG)产生一束水平线偏振光作为水下场景的主动照明。成像探测器是 8 位数字单色 SCMOS 相机(Dhyana400D)。水平和垂直线偏振图像是通过将可旋转的偏振状态分析器(PSA)放置在相机前面获得的。这里的 PSG 和 PSA 都是由线性偏振片组成的。实验浑浊水体采用高透玻璃水槽作为混浊介质容器,4 个内层覆盖黑色吸光纸,避免镜面反射光的影响。通过添加不同体积的中长链脂肪乳注射液控制其浓度模拟不同的散射散射系数。我们将 Intralipid 20% 溶液分别稀释 1 000 倍和 2 000 倍对应高散射与低散射 2 种浑浊度环境。

  • 图1 偏振成像实验装置

  • Fig.1 Schematic of the polarization imaging experimental setup

  • 3.2 成像复原结果的对比

  • 为了验证本文所提出方法的有效性,我们选取了经典的传统强度成像技术、水下偏振差分成像技术[29]、主动偏振去散射方法作为对照方法。对于成像目标,为了验证不同方法的成像适应性,我们选取了金属硬币与刻度尺 2 种不同材质目标。目标本身具有不同的细节信息,且分别为均一底色目标与黑白对照型目标,有利于从不同细节对比最终去散射效果与目标清晰度。

  • 图2 中给出了 4 种成像方法在两种散射程度的成像效果,在低散射环境下,由于背向散射噪声的强度较弱,强度成像的目标信息被噪声部分掩盖,可以分辨轮廓信息,如硬币的形状与尺子的数字刻度信息,偏振差分成像由于低散射不能将介质光充分向正交偏振方向转化导致去散射效果并不显著。经典的主动偏振去散射方法相比于强度成像提升显著,硬币上的汉字与尺子的刻度线被复原。而本文提出的方法进一步实现了背景区域与目标区域噪声的选择性分离,目标信息更加突出。在高散射环境下,强度成像的结果表现为一层浓雾覆盖在目标表面,目标信息已无法辨识,其余 3 种成像方式近乎失效。通过文中所提出的去散射方法,较好地滤除背向散射光,恢复了被衰减的目标信息,如复原后的尺子的黑色刻度与白色背景对比更加突出,更加有利于识别。产生这种现象的主要原因改进模型实现了介质光的全局偏振度分布的准确估算,其直接决定了最终成像效果。2 种散射环境下不同目标类型的成像对比实验证明本方法在强散射环境下去除背景散射噪声的有效性。

  • 3.3 复原图像的无参照图像评价参数对比

  • 之前的分析主要集中于定性的像质对比,为了定量表征不同成像方法的成像效果,我们采用成像对比度 contrast 与图像增强测度 EME(Enhancement Measure Evaluation)对图3 中的复原结果进行了评价参数的计算,2 种参数分别表征了图像局部区域黑白对比梯度与细节的表现能力。其中 EME 被广泛作为评价水下图像质量的无参照指标[30],其原理如下:将整幅图像分为多个区域,分别寻找每个区域中的灰度最大值和最小值,将其代入式即可求出图像的 EME 值,EME 值越大,表明图像细节表现能力越好,视觉效果越好。

  • EME=1k1k2l=1k2 k=1k1 20logimax;k,lω(x,y)imin;k,lω(x,y)+q
    (20)
  • 式中:k1k2指将图像分解为k1×k2块区域;imax; klωxy为每个区域的最大灰度值; imin; klωxy 代表每个区域的最小灰度值; q 取值 0.001。

  • 图2 四种成像方法的对比

  • Fig.2 Comparison of four imaging methods

  • 如表1 与表2 所示,我们给出了 4 种成像方法的评价参数的对比结果。从中可以看出,文中所提出的方法在成像 contrast 与成像 EME 均是最高的。其他方法从高向低依次是主动偏振成像、偏振差分、强度成像。进一步分析可以发现,基于物理退化模型的去散射方法相对于传统的偏振成像技术具有更好的去散射效果,其核心在于对不同区域背景噪声光的选择性抑制。

  • 另外,从表中不同散射系数下的成像结果看,随着散射的加剧,4 种成像方法的成像 contrast 与 EME 均下降明显。强散射环境下偏振成像所面临的主要问题一方面体现在噪声偏振特征与目标信息的偏振特征差异进一步模糊化;另一方面则体现在目标信息被严重衰减,可用信息变少,最终恢复难度增加。

  • 表1 不同成像方法的成像评价参数 contrast 对比

  • Table1 Comparison of contrast with different imaging methods

  • 表2 不同成像方法的成像评价参数 EME 对比

  • Table2 Comparison of EME with different imaging methods

  • 4 结束语

  • 本文充分利用目标反射光的偏振共模抑制特性,提出了一种基于斯托克斯参量的主动偏振去散射成像方法,实现了背向散射光的准确估算,进而实现了噪声的分离与目标信息的重建。通过引入像质的反馈优化参数进一步获得了最优的目标复原结果。不同浑浊程度水体的成像实验结果表明,该方法能够在保留目标信号的前提下,充分滤除后向散射噪声。特别是对于反射型高偏振目标,可以显著改善图像的细节信息和视觉质量。

  • 基于物理模型的主动偏振成像方法相对于纯图像处理方法充分考虑了光线传输的物理过程,通过提取目标与介质偏振特性差异,实现了信噪比的提升,在未来水下光学成像应用中将发挥更大的作用。

  • 参考文献

    • [1] JAFFE J S.Underwater optical imaging:the past,the present,and the prospects[J].IEEE Journal of Oceanic Engineering,2015,40(3):683-700.

    • [2] LIU F,HAN P L,WEI Y,et al.Deeply seeing through highly turbid water by active polarization imaging[J].Optics Letters,2018,43(20):4903-4906.

    • [3] TREIBITZ T,SCHECHNER Y Y.Active polarization descattering[J].IEEE Transactions on Pattern Analysis and Machine Intelligence,2009,31(3):385-399.

    • [4] SCHETTINI R,CORCHS S.Underwater image processing:state of the art of restoration and image enhancement methods[J].EURASIP Journal on Advances in Signal Processing,2010,1:746052.

    • [5] CHIANG J Y,CHEN Y C.Underwater image enhancement by wavelength compensation and dehazing[J].IEEE Transactions on Image Processing,2012,21(4):1756-1769.

    • [6] LI X B,HAN Y L,WANG H Y,et al.Polarimetric imaging through scattering media:a review[J].Frontiers in Physics,2022,10:3389.

    • [7] HE K M,SUN J,TANG X O.Single image haze removal using dark channel prior[J].IEEE Transactions on Pattern Analysis and Machine Intelligence,2011,33(12):2341-2353.

    • [8] AMER K O,ELBOUZ M,ALFALOU A,et al.Enhancing underwater optical imaging by using a low-pass polarization filter[J].Optics Express,2019,27(2):621-643.

    • [9] TANG A P.A restoration of underwater polarized images based on DCP[C]//2019 International Conference on Sensing,Diagnostics,Prognostics,and Control(SDPC).Beijing:IEEE,2019.

    • [10] CHEN X W,JIN M Y,CHEN H L,et al.Computational temporal ghost imaging for long-distance underwater wireless optical communication[J].Optics Letters,2021,46(8):1938-1941.

    • [11] SCHECHNER Y Y,KARPEL N.Recovery of underwater visibility and structure by polarization analysis [J].IEEE Journal of Oceanic Engineering,2005,30(3):570-587.

    • [12] LI X B,XU J N,ZHANG L P,et al.Underwater image restoration via Stokes decomposition[J].Optics Letters,2022,47(11):2854-2857.

    • [13] HU H F,ZHANG Y B,LI X B,et al.Polarimetric underwater image recovery via deep learning[J].Optics and Lasers in Engineering,2020,133:106152.

    • [14] REN Q M,XIANG Y F,WANG G C,et al.The underwater polarization dehazing imaging with a lightweight convolutional neural network[J].Optik,2022,251:168381.

    • [15] HU H F,HAN Y L,LI X B,et al.Physics-informed neural network for polarimetric underwater imaging[J].Optics Express,2022,30(13):22512-22522.

    • [16] HU H F,ZHAO L,LI X B,et al.Underwater image recovery under the nonuniform optical field based on polarimetric imaging[J].IEEE Photonics Journal,2018,10(1):1-9.

    • [17] HU H F,ZHAO L,HUANG B J,et al.Enhancing visibility of polarimetric underwater image by transmittance correction[J].IEEE Photonics Journal,2017,9(3):1-10.

    • [18] HUANG B J,LIU T G,HU H F,et al.Underwater image recovery considering polarization effects of objects[J].Optics Express,2016,24(9):9826-9838.

    • [19] JIN L L,HONG L.Deep learning for underwater image recognition in small sample size situations[C]//Oceans 2017.Aberdeen:IEEE,2017.

    • [20] HAN P L,LIU F,WEI Y,et al.Optical correlation assists to enhance underwater polarization imagingperformance[J].Optics and Lasers in Engineering,2020,134:106256.

    • [21] DUBREUIL M,DELROT P,LEONARD I,et al.Exploring underwater target detection by imaging polarimetry and correlation techniques[J].Applied Optics,2013,52(5):997-1005.

    • [22] ZHANG H J,REN M Y,WANG H T,et al.Fast processing of underwater polarization imaging based on optical correlation[J].Applied Optics,2021,60(15):4462-4468.

    • [23] GUAN J G,ZHAO Y,ZHENG Y Q,et al.Optical polarization imaging for underwater target detection with non-scatter background[J].Journal of Measurement Science & Instrumentation,2020,11(4):335-342.

    • [24] HU H F,LI J Q,LI X B,et al.Underwater polarization difference imaging with three degrees of freedom[J].Acta Optica Sinica,2021,41(3):0329001.

    • [25] YANG S L,QU B W W,LIU G S,et al.Unsupervised learning polarimetric underwater image recovery under nonuniform optical fields[J].Applied Optics,2021,60(26):8198-8205.

    • [26] YU T,WANG X L,XI S X,et al.Underwaterpolarization imaging for visibility enhancement of moving targets in turbid environments[J].Optics Express,2023,31(1):459-468.

    • [27] ZHAO Y Z,HE W J,REN H,et al.Polarization descattering imaging through turbid water without prior knowledge[J].Optics and Lasers in Engineering,2022,148(23-24):106777.

    • [28] LIANG J,JU H J,REN L Y,et al.Generalized polarimetric dehazing method based on low-pass filtering in frequency domain[J].Sensors,2020,20(6):1729.

    • [29] TIAN H,ZHU J P,TAN S W,et al.Rapid underwater target enhancement method based on polarimetric imaging[J].Optics & Laser Technology,2018,108:515-520.

    • [30] PANETTA K A,WHARTON E J,AGAIAN S S.Human visual system-based image enhancement and logarithmic contrast measure[J].IEEE Transactions on Systems,Man,and Cybernetics.Part B:Cybernetics,2008,38(1):174-188.

  • 参考文献

    • [1] JAFFE J S.Underwater optical imaging:the past,the present,and the prospects[J].IEEE Journal of Oceanic Engineering,2015,40(3):683-700.

    • [2] LIU F,HAN P L,WEI Y,et al.Deeply seeing through highly turbid water by active polarization imaging[J].Optics Letters,2018,43(20):4903-4906.

    • [3] TREIBITZ T,SCHECHNER Y Y.Active polarization descattering[J].IEEE Transactions on Pattern Analysis and Machine Intelligence,2009,31(3):385-399.

    • [4] SCHETTINI R,CORCHS S.Underwater image processing:state of the art of restoration and image enhancement methods[J].EURASIP Journal on Advances in Signal Processing,2010,1:746052.

    • [5] CHIANG J Y,CHEN Y C.Underwater image enhancement by wavelength compensation and dehazing[J].IEEE Transactions on Image Processing,2012,21(4):1756-1769.

    • [6] LI X B,HAN Y L,WANG H Y,et al.Polarimetric imaging through scattering media:a review[J].Frontiers in Physics,2022,10:3389.

    • [7] HE K M,SUN J,TANG X O.Single image haze removal using dark channel prior[J].IEEE Transactions on Pattern Analysis and Machine Intelligence,2011,33(12):2341-2353.

    • [8] AMER K O,ELBOUZ M,ALFALOU A,et al.Enhancing underwater optical imaging by using a low-pass polarization filter[J].Optics Express,2019,27(2):621-643.

    • [9] TANG A P.A restoration of underwater polarized images based on DCP[C]//2019 International Conference on Sensing,Diagnostics,Prognostics,and Control(SDPC).Beijing:IEEE,2019.

    • [10] CHEN X W,JIN M Y,CHEN H L,et al.Computational temporal ghost imaging for long-distance underwater wireless optical communication[J].Optics Letters,2021,46(8):1938-1941.

    • [11] SCHECHNER Y Y,KARPEL N.Recovery of underwater visibility and structure by polarization analysis [J].IEEE Journal of Oceanic Engineering,2005,30(3):570-587.

    • [12] LI X B,XU J N,ZHANG L P,et al.Underwater image restoration via Stokes decomposition[J].Optics Letters,2022,47(11):2854-2857.

    • [13] HU H F,ZHANG Y B,LI X B,et al.Polarimetric underwater image recovery via deep learning[J].Optics and Lasers in Engineering,2020,133:106152.

    • [14] REN Q M,XIANG Y F,WANG G C,et al.The underwater polarization dehazing imaging with a lightweight convolutional neural network[J].Optik,2022,251:168381.

    • [15] HU H F,HAN Y L,LI X B,et al.Physics-informed neural network for polarimetric underwater imaging[J].Optics Express,2022,30(13):22512-22522.

    • [16] HU H F,ZHAO L,LI X B,et al.Underwater image recovery under the nonuniform optical field based on polarimetric imaging[J].IEEE Photonics Journal,2018,10(1):1-9.

    • [17] HU H F,ZHAO L,HUANG B J,et al.Enhancing visibility of polarimetric underwater image by transmittance correction[J].IEEE Photonics Journal,2017,9(3):1-10.

    • [18] HUANG B J,LIU T G,HU H F,et al.Underwater image recovery considering polarization effects of objects[J].Optics Express,2016,24(9):9826-9838.

    • [19] JIN L L,HONG L.Deep learning for underwater image recognition in small sample size situations[C]//Oceans 2017.Aberdeen:IEEE,2017.

    • [20] HAN P L,LIU F,WEI Y,et al.Optical correlation assists to enhance underwater polarization imagingperformance[J].Optics and Lasers in Engineering,2020,134:106256.

    • [21] DUBREUIL M,DELROT P,LEONARD I,et al.Exploring underwater target detection by imaging polarimetry and correlation techniques[J].Applied Optics,2013,52(5):997-1005.

    • [22] ZHANG H J,REN M Y,WANG H T,et al.Fast processing of underwater polarization imaging based on optical correlation[J].Applied Optics,2021,60(15):4462-4468.

    • [23] GUAN J G,ZHAO Y,ZHENG Y Q,et al.Optical polarization imaging for underwater target detection with non-scatter background[J].Journal of Measurement Science & Instrumentation,2020,11(4):335-342.

    • [24] HU H F,LI J Q,LI X B,et al.Underwater polarization difference imaging with three degrees of freedom[J].Acta Optica Sinica,2021,41(3):0329001.

    • [25] YANG S L,QU B W W,LIU G S,et al.Unsupervised learning polarimetric underwater image recovery under nonuniform optical fields[J].Applied Optics,2021,60(26):8198-8205.

    • [26] YU T,WANG X L,XI S X,et al.Underwaterpolarization imaging for visibility enhancement of moving targets in turbid environments[J].Optics Express,2023,31(1):459-468.

    • [27] ZHAO Y Z,HE W J,REN H,et al.Polarization descattering imaging through turbid water without prior knowledge[J].Optics and Lasers in Engineering,2022,148(23-24):106777.

    • [28] LIANG J,JU H J,REN L Y,et al.Generalized polarimetric dehazing method based on low-pass filtering in frequency domain[J].Sensors,2020,20(6):1729.

    • [29] TIAN H,ZHU J P,TAN S W,et al.Rapid underwater target enhancement method based on polarimetric imaging[J].Optics & Laser Technology,2018,108:515-520.

    • [30] PANETTA K A,WHARTON E J,AGAIAN S S.Human visual system-based image enhancement and logarithmic contrast measure[J].IEEE Transactions on Systems,Man,and Cybernetics.Part B:Cybernetics,2008,38(1):174-188.