Degradation and optimal recovery of underwater turbulent imaging

Chen Yuzhang; Ye Ting; Cheng Chaojie; Yang Wanlu

doi:10.12086/oee.2018.180233

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Chen Yuzhang, Ye Ting, Cheng Chaojie, et al. Degradation and optimal recovery of underwater turbulent imaging[J]. Opto-Electronic Engineering, 2018, 45(12): 180233. doi: 10.12086/oee.2018.180233

Citation:

Chen Yuzhang, Ye Ting, Cheng Chaojie, et al. Degradation and optimal recovery of underwater turbulent imaging[J]. Opto-Electronic Engineering, 2018, 45(12): 180233. doi: 10.12086/oee.2018.180233

Degradation and optimal recovery of underwater turbulent imaging

1.
School of Computer Science and Information Engineering, Hubei University, Wuhan, Hubei 430062, China
2.
School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China

Fund Project: Supported by Research Project of Hubei Provincial Department of Education in China (Q20171010)

More Information

Corresponding author: Ye Ting, E-mail:630197027@qq.com

Received Date 30 April 2018

Revised Date 05 July 2018

Published Date 01 December 2018

Abstract

Abstract

In order to comprehensively and objectively study the degenerate factors of underwater turbulent imaging and optimize the corresponding image restoration algorithms, a reusable submarine imaging experiment system with a controllable turbulent flow condition is established. The circulating water pump is used to control the intensity of turbulence in the laboratory tank.The bubble generator is used to generate micro bubbles. The image sensor is used to obtain the images of sinusoidal stripe target plates under different conditions. The effect of turbulent flow field, path radiation and fluid media on submarine imaging in turbulent flow were studied, and the differences and applicability of modulation transfer functions (MTFs) of three degradation factors are compared by combining image restoration and super-resolution reconstruction. The experimental results show that the turbulent flow field causes MTF declines of the low spatial frequency, and the path radiation and fluid media lead to the decrease of modulation contrast of the high spatial frequency. In the restoration of the underwater turbulent degraded image, the MTF of the turbulent flow field is suitable for image restoration, and the MTFs of the path radiation and fluid media are suitable for image reconstruction.
- oceanic optics /
- modulation transfer function /
- image reconstruction-restoration /
- superresolution

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References

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Overview

Overview

Overview: At present, the related researches of underwater turbulence mainly include three major categories. The first category is the theoretical calculation based on turbulent structure function and scattering properties. The second category is to use the refractive index power spectra to construct experimental systems for indoor or outdoor experimental measurements and analysis. The third category is the simulation testing based on the PIV system. The existing three categories of research methods have different emphases, and few literatures compare them.

In order to comprehensively and objectively study the degenerate factors of underwater turbulent imaging and optimize the corresponding image restoration algorithms, a reusable submarine imaging experiment system with a turbulent flow controllable condition is established. The circulating water pump is used to provide water force, and the water valve is used to control the turbulent flow field in the laboratory tank. The bubble generator is used to generate micro bubbles, and the bubbles is used as tracer particles. Image sensor is used to obtain the images of sinusoidal stripe target plates under different conditions. In order to reduce the experimental error, the experiment is conducted in a dark environment.
Through indoor and outdoor field experiments, the effect of turbulent flow field, path radiation and fluid media on submarine imaging in turbulent flow are studied. The modulation transfer function (MTF) of the underwater turbulence degradation is correspondingly extracted and analyzed for the three models. The adaptation performance and advantages of the three MTFs are compared and analyzed by using several typical image processing algorithms in turbulent image restoration and super-resolution reconstruction. The objective evaluation criteria such as information capacity (IC), blur metric (BM), and gray mean grads (GMG) are used to compare the objective effect of image processing. The experimental results show that the turbulent flow field, path radiation and fluid media affect the underwater imaging process in turbulent water. The turbulent flow field is the main factor that causes the degradation of underwater imaging in the low spatial frequency. The path radiation and fluid media are the main causes of image degradation. In the restoration of the underwater turbulent degraded image, the MTF of the turbulent flow field is suitable for the image restoration, and the MTFs of the path radiation and turbulent fluid media are suitable for the image super-resolution reconstruction. Compared with other methods of the same class, the information capacity and the gray mean grads value are larger and the blur metric value is smaller.