Sonar watermark embedding and detection: a sea trial report

2012 ◽  
Author(s):  
Bijan G. Mobasseri ◽  
Nagarjun Chakilam ◽  
Robert S. Lynch
Keyword(s):  
Trial Report ◽  
Sea Trial ◽  
Watermark Embedding

scholarly journals Seabed Terrain 3D Reconstruction Using 2D Forward-Looking Sonar: A Sea-Trial Report From The Pipeline Burying Project

2019 ◽  
Vol 52 (21) ◽  
pp. 175-180
Author(s):  
Sanming Song ◽  
Yan Li ◽  
Zhigang Li ◽  
Zhiqiang Hu ◽  
Shuo Li ◽  
...  
Keyword(s):  
3D Reconstruction ◽  
Trial Report ◽  
Sea Trial ◽  
Forward Looking

A Study of the Sealing Performance of a New High-Pressure Cone Valve for Deep-Sea Gas-Tight Water Samplers

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Shi-Jun Wu ◽  
Can-Jun Yang ◽  
Ying Chen ◽  
Yan-Qing Xie
Keyword(s):  
Finite Element Analysis ◽  
High Pressure ◽  
Deep Sea ◽  
Hydrothermal Fluid ◽  
Contact Model ◽  
Element Analysis ◽  
Sea Trial ◽  
Sealing Performance ◽  
Pressure Cone ◽  
Gas Tight

The cone valve plays an important role in high-pressure sealing applications. In this paper, a new high-pressure cone valve, based on the titanium alloy poppet-to-polyetheretherketone seat sealing structure, is proposed for deep-sea gas-tight water samplers. In order to study the sealing performance of the new valve, both the conforming poppet-seat contact model and the nonconforming poppet-seat contact model were evaluated. Finite element analysis based on the two models was performed and validated by experiments. The results indicate that the nonconforming poppet-seat contact model has a better sealing performance than the conforming poppet-seat contact model. The new cone valve also was applied in a gas-tight hydrothermal fluid sampler and successfully tested in a sea trial during the KNOX18RR cruise from 9 July to 12 August 2008.

Anti-Print and Scan Halftone Watermarking Algorithm Based on Edge Detection

2013 ◽  
Vol 416-417 ◽  
pp. 1210-1213
Author(s):  
Hua Wen Ai ◽  
Ping Feng Liu ◽  
Sheng Cong Dong
Keyword(s):  
Edge Detection ◽  
Image Watermarking ◽  
Error Diffusion ◽  
Grayscale Image ◽  
Good Resistance ◽  
Visibility Function ◽  
Gray Image ◽  
Halftone Image ◽  
Watermark Embedding ◽  
Edge Points

In order to resist print and scan attacks, a kind of digital halftone image watermarking algorithm is proposed, which is based on the edge detection and improved error diffusion. The edge of gray image is gotten using canny detection. Calculate the noise visibility function values of the edge points. Then, sort the values in ascending order and select the size that equal to the length of watermark as the location of watermark embedding. While the grayscale image turns to halftone image using the improved error diffusion algorithm, binary watermark is embedded in the edge position. Watermark is pretreated with Arnold before embedding to improve the safety of watermark. Experiment results show that the algorithm is good resistance to print and scan attacks, while resistance to shearing, noise and jpeg compression attacks.

Watermark embedding in optimal color direction

2013 ◽  
Author(s):  
Robert Lyons ◽  
Alastair Reed ◽  
John Stach
Keyword(s):  
Watermark Embedding

scholarly journals The Estimation of Angular Misalignments for Ultra Short Baseline Navigation Systems. Part II: Experimental Results

2013 ◽  
Vol 66 (5) ◽  
pp. 773-787 ◽  
Author(s):  
Hsin-Hung Chen
Keyword(s):  
Trial Data ◽  
Experimental Results ◽  
Experimental Result ◽  
Alignment Error ◽  
Navigation Systems ◽  
Analytical Prediction ◽  
Short Baseline ◽  
Sea Trial ◽  
Alignment Errors ◽  
Cross Track

An algorithm of alignment calibration for Ultra Short Baseline (USBL) navigation systems was presented in the companion work (Part I). In this part (Part II) of the paper, this algorithm is tested on the sea trial data collected from USBL line surveys. In particular, the solutions to two practical problems referred to as heading deviation and cross-track error in the USBL line survey are presented. A field experiment running eight line surveys was conducted to collect USBL positioning data. The numerical results for the sea trial data demonstrated that the proposed algorithm could robustly and effectively estimate the alignment errors. Comparisons of the experimental result with the analytical prediction of roll misalignment estimation in Part I is drawn, showing good agreement. The experimental results also show that an inappropriate estimation of roll alignment error will significantly degrade the quality of estimations of heading and pitch alignment errors.

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