Temporal Model of Underwater Laser Range-Gated Imaging and Pulse Stretching

Youwei, 黄有为 Huang; Xia, 王霞 Wang; Weiqi, 金伟其 Jin; Kun, 丁琨 Ding; Hailan, 李海兰 Li; Jing, 刘敬 Liu

doi:10.3788/aos20103011.3177

Cited by 2 publications

(1 citation statement)

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“…Laser range gated imaging system is widely used in underwater detection [1][2], night target imaging [3][4] and military reconnaissance and other aspects. Range gated imaging adopts the idea of slice imaging [5], through the control of photon flight time, environmental backscattered signals can be effectively shielded to improve the detection and imaging distance. In the general sense [6][7], single imaging only selects the target at a fixed distance.…”

Section: Introductionmentioning

confidence: 99%

Research on coding method of underwater full range gated lidar

Jin,

Wang,

Pei

et al. 2023

Ninth Symposium on Novel Photoelectronic Detection Technology and Applications

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Section: Introductionmentioning

confidence: 99%

Research on coding method of underwater full range gated lidar

Jin,

Wang,

Pei

et al. 2023

Ninth Symposium on Novel Photoelectronic Detection Technology and Applications

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Image contrast for different imaging methods in turbid media

Tian¹,

Zhu²,

Zhang³

et al. 2016

Acta Phys. Sin.

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The physics-based methods that can effectively improve the image contrast in turbid media while truly preserving all the detailed information, have received great attention in recent years. The range-gated imaging (RGI), polarization difference method (PD) and polarization-based range-gated technology (PRG) are three effective methods of enhancing the contrast. However, the relationship between the extent of contrast enhancement and the imaging distance for each method has not been revealed. In this paper, a compact disc (CD) plate is set to be in the intralipid with different concentrations contained in a glass cell and imaged by RGI, PD, PRG and raw intensity imaging (RI). The Indian ink is used as the absorber which eliminates the multiple scattered photons and achieves the range-gated technology. In order to investigate the number of the scattered photons filtered out by the 4 methods, the image intensity curves are acquired while the imaging distance, the distance between the target surface and the front surface of the cell, is set to be 26 mm. The results indicate that PRG filters out the largest number of the scattered photons, followed by PD and RGI because the long imaging distance results in more multiple scattering photons. Then the influence of the imaging distance on the image intensity is investigated by the 4 methods. The image intensity is recorded while the imaging distance varies from 22 mm to 30 mm with even increments. Then four sets of intensity curves are plotted against the imaging distance corresponding to RI, RGI, PD and PRG respectively. Based on the RI, three sets of image intensity difference curves of RGI, PD and PRG are also calculated. The tendencies of the curves show that these imaging methods have their own imaging distance thresholds. It implies that the numbers of the photons filtered out by these methods are all constant when their imaging distances exceed their thresholds of 22 mm, 30 mm and 30 mm, respectively. Finally, the effect of the imaging distance on the contrast variation is studied in turbid media with two different scattering coefficient 0.714 cm-1 and 1.19 cm-1. The results show that PRG is superior to other methods in contrast enhancement. In addition, the imaging distances of the 4 methods under the same image contrast are obtained, showing that under the same contrast increment, the PRG presents the largest imaging distance enhancement, followed by PD, RGI and RI. The increase of scattering coefficient could also cause the decrease of the imaging distance. These results can be very useful to understand the mechanism of imaging in turbid media and are of great significance for improving the ability to recognize the target.

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Temporal Model of Underwater Laser Range-Gated Imaging and Pulse Stretching

Cited by 2 publications

References 0 publications

Research on coding method of underwater full range gated lidar

Research on coding method of underwater full range gated lidar

Image contrast for different imaging methods in turbid media

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