A new video monitoring system in support of Coastal Zone Management at Apulia Region, Italy

Valentini, Nico; Saponieri, Alessandra; Damiani, Leonardo

doi:10.1016/j.ocecoaman.2017.03.032

Cited by 31 publications

(24 citation statements)

References 35 publications

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“…This enabled the errors in projecting a given pixel when the lens distortion is neglected to be assessed. A camera calibration routine to determine the intrinsic and extrinsic camera parameters was used, similar to the one proposed by Zhang [42] and implemented by Valentini et al [43]. For the conditions and zoom setting used in Reñaca, this led to errors in placement that did not exceed one pixel.…”

Section: Discussionmentioning

confidence: 99%

Assessing the Performance of a Low-Cost Method for Video-Monitoring the Water Surface and Bed Level in the Swash Zone of Natural Beaches

et al. 2018

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A method to continuously measure bed and water levels along a cross-shore transect of vertical poles is evaluated. This remote sensing based method uses video imagery of swash flows propagating past an array of vertical poles buried on the beach face. Using datasets collected at two beaches in Chile, the method is compared against measurements obtained with conventional co-localized instruments: LiDAR and ultrasonic distance meters. The present video swash pole technique shows good skill in retrieving swash zone bed level and water levels, while providing the possibility to measure morphological variations at time scales varying from wave groups (tens of seconds) to hours. Discrepancies between video and ultrasonic distance meters are found when short time scales are used, for both depositional and erosion events, but longer duration trends are captured well. Water surface elevations at the wave-by-wave scale proved to be accurate for the backwash phase (root-mean-sqaure-error, RMSE down to 0.028 m, R 2 up to 0.89), when compared against LiDAR. However, discrepancies have been found during the uprush phase (RMSE up to 0.062 m, R 2 down to 0.71), when the influence of the pole on the swash flow generates an overestimation of the water surface. Overall, owing to its simplicity of deployment, low cost and reasonable accuracy, the technique is considered suitable for swash studies.

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Section: Discussionmentioning

confidence: 99%

Assessing the Performance of a Low-Cost Method for Video-Monitoring the Water Surface and Bed Level in the Swash Zone of Natural Beaches

et al. 2018

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“…Among the coastal video monitoring techniques, ground-sensing approaches by means of camera systems are widely used, allowing the investigation of coastal processes with high temporal and spatial resolution, with optimal accuracy. Numerous alternative or complementary uses are also pursued, with applications related to coastal hydrodynamics [1][2][3][4], morphodynamics [5][6][7], or quality monitoring (e.g., seagrass) [8,9]. Moreover, the use of low-cost devices and public resources has recently become a focus of attention and is being further explored [10][11][12].…”

Section: Image Classification-coastal Areamentioning

confidence: 99%

Assessment of a Smartphone-Based Camera System for Coastal Image Segmentation and Sargassum monitoring

Valentini

Balouin

2020

JMSE

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Coastal video monitoring has proven to be a valuable ground-based technique to investigate ocean processes. Presently, there is a growing need for automatic, technically efficient, and inexpensive solutions for image processing. Moreover, beach and coastal water quality problems are becoming significant and need attention. This study employs a methodological approach to exploit low-cost smartphone-based images for coastal image classification. The objective of this paper is to present a methodology useful for supervised classification for image semantic segmentation and its application for the development of an automatic warning system for Sargassum algae detection and monitoring.A pixel-wise convolutional neural network (CNN) has demonstrated optimal performance in the classification of natural images by using abstracted deep features. Conventional CNNs demand a great deal of resources in terms of processing time and disk space. Therefore, CNN classification with superpixels has recently become a field of interest. In this work, a CNN-based deep learning framework is proposed that combines sticky-edge adhesive superpixels. The results indicate that a cheap camera-based video monitoring system is a suitable data source for coastal image classification, with optimal accuracy in the range between 75% and 96%. Furthermore, an application of the method for an ongoing case study related to Sargassum monitoring in the French Antilles proved to be very effective for developing a warning system, aiming at evaluating floating algae and algae that had washed ashore, supporting municipalities in beach management.

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“…Different representative nearshore bathymetries were used, all derived from bathymetric surveys, and depicting different steps of the morphological changes observed following SBW implementation (Section 3.3). To complete the survey in shallow water, the shoreline was extracted from video images (Section 3.3) using a shoreline detection method based on a boundary extraction procedure from the automatic segmented coastal area [51]. Given the abrupt water depth changes across the SBW, owing to the sandbag shape, the structure was implemented schematically according to grid resolution.…”

Section: Model Setupmentioning

confidence: 99%

Modeling the Impact of the Implementation of a Submerged Structure on Surf Zone Sandbar Dynamics

Bouvier

Castelle

Balouin³

2019

JMSE

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Coastal defense strategies based on structures are increasingly unpopular as they are costly, leave lasting scars on the landscape, and sometimes have limited effectiveness or even adverse impacts. While a clear improvement concerning aesthetic considerations using soft submerged breakwater is undeniable, their design has often focused on wave transmission processes across the crest of the structure, overlooking short- to medium-term morphodynamic responses. In this study, we used a time- and depth-averaged morphodynamic model to investigate the impact of the implementation of a submerged breakwater on surf zone sandbar dynamics at the beach of Sète, SE France. The hydrodynamic module was calibrated with data collected during a field experiment using three current profilers deployed to capture rip-cell circulation at the edge of the structure. The model showed good agreement with measurements, particularly for the longshore component of the flow (RMSE = 0.07 m/s). Results showed that alongshore differential wave breaking at the edge of the submerged breakwater drove an intense (0.4 m/s) two-dimensional circulation for low- to moderate-energy waves. Simulations indicated that inner-bar rip channel development, which was observed prior to the submerged reef implementation, was inhibited in the lee of the structure as rip-cell circulation across the inner bar disappeared owing to persistently low-energy breaking waves. The cross-shore sandbar dynamics in the lee of the structure were also impacted due to the drastic decrease of the offshore-directed flow over the inner-bar during energetic events. This paper highlights that implementation of a submerged breakwater results in larges changes in nearshore hydrodynamics that, in turn, can affect overall surf zone sandbar behavior.

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A new video monitoring system in support of Coastal Zone Management at Apulia Region, Italy

Cited by 31 publications

References 35 publications

Assessing the Performance of a Low-Cost Method for Video-Monitoring the Water Surface and Bed Level in the Swash Zone of Natural Beaches

Assessing the Performance of a Low-Cost Method for Video-Monitoring the Water Surface and Bed Level in the Swash Zone of Natural Beaches

Assessment of a Smartphone-Based Camera System for Coastal Image Segmentation and Sargassum monitoring

Modeling the Impact of the Implementation of a Submerged Structure on Surf Zone Sandbar Dynamics

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