scholarly journals DEPTH RETRIEVAL FROM A RESERVOIR USING A CONDITIONAL-BASED MODEL

2020 ◽  
Vol XLII-3/W12-2020 ◽  
pp. 231-235
Author(s):  
M. B. Nunes ◽  
A. P. Dal Poz ◽  
E. Alcântara ◽  
M. Curtarelli
Keyword(s):  
Water Depth ◽  
Empirical Models ◽  
Depth Information ◽  
Single Model ◽  
Important Measure ◽  
Multispectral Sensors

Abstract. Water depth is an important measure for nautical charts. Accurate methods to provide water depth information are expensive and time costing. For this reason, since late 70’s, it started to be estimate by multispectral sensors with empirical models. In the literature there is no investigation using empirical models partitioned in depth intervals, for this reason, we evaluated the accuracy of partitioned and single bathymetric models. The results have shown that to retrieve depth in from 0 to 15 m the single model provided an RMSE of 3.57 m, with a bias of about −0.83 m; while the RMSE for the partitioned model was 2.29 m with a bias of 0.41 m. For updating nautical charts using multispectral sensors it was concluded that the partitioned model can provide a better result than using a single model.

scholarly journals LSTM-Based Remote Sensing Inversion of Largescale Sand Wave Topography of the Taiwan Banks

2021 ◽  
Vol 13 (16) ◽  
pp. 3313
Author(s):  
Yujin Zhao ◽  
Liaoying Zhao ◽  
Huaguo Zhang ◽  
Bin Fu
Keyword(s):  
Remote Sensing ◽  
Water Depth ◽  
Short Term Memory ◽  
Sand Wave ◽  
Depth Information ◽  
Sand Waves ◽  
Practical Applications ◽  
Sea Sand ◽  
Wave Region ◽  
Memory Network

Shallow underwater topography has important practical applications in fisheries, navigation, and pipeline laying. Traditional multibeam bathymetry is limited by the high cost of largescale topographic surveys in large, shallow sand wave areas. Remote sensing inversion methods to detect shallow sand wave topography in Taiwan rely heavily on measured water depth data. To address these problems, this study proposes a largescale remote sensing inversion model of sand wave topography based on long short-term memory network machine learning. Using multi-angle sun glitter remote sensing to obtain sea surface roughness (SSR) information and by learning and training SSR and its corresponding water depth information, the sand wave topography of a largescale shallow sea sand wave region is extracted. The accuracy of the model is validated through its application to a 774 km2 area in the sand wave topography of the Taiwan Banks. The model obtains a root mean square error of 3.31–3.67 m, indicating that the method has good generalization capability and can achieve a largescale topographic understanding of shallow sand waves with some training on measured bathymetry data. Sand wave topography is widely present in tidal environments; our method has low requirements for ground data, with high application value.

scholarly journals Accurate Refraction Correction—Assisted Bathymetric Inversion Using ICESat-2 and Multispectral Data

2021 ◽  
Vol 13 (21) ◽  
pp. 4355
Author(s):  
Changda Liu ◽  
Jiawei Qi ◽  
Jie Li ◽  
Qiuhua Tang ◽  
Wenxue Xu ◽  
...  
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Incidence Angle ◽  
Correction Method ◽  
Emission Angle ◽  
Sea Surface ◽  
Depth Information ◽  
Multispectral Data ◽  
Position Correction ◽  
Shallow Water Depth

Shallow-water depth information is essential for ship navigation and fishery farming. However, the accurate acquisition of shallow-water depth has been a challenge for marine mapping. Combining Ice, Cloud, and Land Elevation Satellite-2 (ICESat-2) bathymetry data with multispectral data, satellite-derived bathymetry is a promising solution through which to obtain bathymetric information quickly and accurately. This study proposes a photon refraction correction method considering sea-surface undulations to address errors in the underwater photons obtained by the ICESat-2. First, the instantaneous sea surface and beam emission angle are integrated to determine the sea-surface incidence angle. Next, the distance of photon propagation in water is determined using sea-surface undulation and Snell’s law. Finally, position correction is performed through geometric relationships. The corrected photons were combined with the multispectral data for bathymetric inversion, and a bathymetric map of the Yongle Atoll area was obtained. A bathymetric chart was created using the corrected photons and the multispectral data in the Yongle Atoll. Comparing the results of different refraction correction methods with the data measured shows that the refraction correction method proposed in this paper can effectively correct bathymetry errors: the root mean square error is 1.48 m and the R2 is 0.86.

scholarly journals The importance of Atmospheric Correction for Airborne Hyperspectral Remote Sensing of Shallow Waters. Application to Depth Estimation

2017 ◽  
Author(s):  
Elena Castillo-López ◽  
Jose Antonio Dominguez ◽  
Raúl Pereda ◽  
Julio Manuel de Luis ◽  
Ruben Pérez ◽  
...  
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Accurate Determination ◽  
Atmospheric Correction ◽  
Principal Component ◽  
Depth Estimation ◽  
Correction Method ◽  
Shallow Waters ◽  
Depth Information ◽  
Cross Track

Abstract. Abstract. Accurate determination of water depth is indispensable in multiple aspects of civil engineering (dock construction, dikes, submarines outfalls, trench control, etc.). According to the final objective, different accuracies will be required. Accuracy in bathymetric information is highly dependent on the atmospheric correction made to the imagery. The reduction of effects such as glint and cross track illumination in shallow-water areas with homogeneous improves the results of the depth estimations. The aim of this work is to assess the best atmospheric correction method for the estimation of depth in shallow waters. This paper addresses the use of hyperspectral imagery to quantitative bathymetric mapping, and explores one of the most common problems when attempting to extract depth information in conditions of variable water types and bottom reflectances. The current work assesses the accuracy of some classical bathymetric algorithms (Polcyn-Lyzenga, Philpot, Benny-Dawson, Hamilton, Principal Component Analysis) when four different atmospheric correction methods are applied and water depth is derived. This work shows the importance of atmospheric correction in order to depth estimation in shallow waters. None atmospheric correction is valid for all type of coastal waters but in heterogeneous shallow water, the model of atmospheric correction 6S offers good results.

scholarly journals The importance of atmospheric correction for airborne hyperspectral remote sensing of shallow waters: application to depth estimation

2017 ◽  
Vol 10 (10) ◽  
pp. 3919-3929 ◽  
Author(s):  
Elena Castillo-López ◽  
Jose Antonio Dominguez ◽  
Raúl Pereda ◽  
Julio Manuel de Luis ◽  
Ruben Pérez ◽  
...  
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Accurate Determination ◽  
Atmospheric Correction ◽  
Principal Component ◽  
Depth Estimation ◽  
Correction Method ◽  
Shallow Waters ◽  
Depth Information ◽  
Cross Track

Abstract. Accurate determination of water depth is indispensable in multiple aspects of civil engineering (dock construction, dikes, submarines outfalls, trench control, etc.). To determine the type of atmospheric correction most appropriate for the depth estimation, different accuracies are required. Accuracy in bathymetric information is highly dependent on the atmospheric correction made to the imagery. The reduction of effects such as glint and cross-track illumination in homogeneous shallow-water areas improves the results of the depth estimations. The aim of this work is to assess the best atmospheric correction method for the estimation of depth in shallow waters, considering that reflectance values cannot be greater than 1.5 % because otherwise the background would not be seen. This paper addresses the use of hyperspectral imagery to quantitative bathymetric mapping and explores one of the most common problems when attempting to extract depth information in conditions of variable water types and bottom reflectances. The current work assesses the accuracy of some classical bathymetric algorithms (Polcyn–Lyzenga, Philpot, Benny–Dawson, Hamilton, principal component analysis) when four different atmospheric correction methods are applied and water depth is derived. No atmospheric correction is valid for all type of coastal waters, but in heterogeneous shallow water the model of atmospheric correction 6S offers good results.

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