Operational Use of Surfcam Online Streaming Images for Coastal Morphodynamic Studies

Abstract

Coastal video monitoring has been proven to be a valuable shore-based remote-sensing technique to study coastal processes, as it offers the possibility of high-frequency, continuous and autonomous observations of the coastal area. However, the installation of a video systems infrastructure requires economical and technical efforts, along with being often limited by logistical constraints. This study presents methodological approaches to exploit “surfcam” internet streamed images for quantitative scientific studies. Two different methodologies to collect the required ground control points (GCPs), both during fieldwork and using web tools freely available are presented, in order to establish a rigorous geometric connection between terrestrial and image spaces. The application of an image projector tool allowed the estimation of the unknown camera parameters necessary to georectify the online streamed images. Three photogrammetric procedures are shown, distinct both in the design of the computational steps and in number of GCPs available to solve the spatial resection system. Results showed the feasibility of the methodologies to generate accurate rectified planar images, with the best horizontal projection accuracy of 1.3 m compatible with that required for a quantitative analysis of coastal processes. The presented methodologies can turn “surfcam” infrastructures and any online streaming beach cam, into fully remote shore-based observational systems, fostering the use of these freely available images for the study of nearshore morphodynamics.

Breaking Wave Height Estimation from Timex Images: Two Methods for Coastal Video Monitoring Systems

“…The use of Timex is opportunistic also because it allows sampling multiple arrays of transects over alongshore domain, hence characterizing breaking wave height over the whole monitored area, without the need of producing a Timestack image for each transect of interest. Finally, both methods can be directly coupled to the numerous applications that use Timex properties for studying coastal processes [14,16,40,41].…”

“…Image frames (image size 800 × 450) were extracted from the video burst at 5 Hz to generate 10-min Timex images for two days, 28 and 29 March 2017 ( Figure 1). Images were rectified at the corresponding water level [14,25] with a spatial image resolution of 1 m 2 pixel footprint. Ten-minute Timestack images were also produced along the cross-shore transect perpendicular to the wave propagation direction, with 1 m spatial and 1 s The camera is an online streaming Internet Protocol (IP) device installed by the company Surftotal (www.surftotal.com) on the roof of a house, at an elevation of about 80 m above Mean Sea Level (MSL) and at a distance of 400 m from the shore.…”

“…Coastal video monitoring is a shore-based remote sensing technique that uses images acquired by optical devices installed on an elevated position collecting high-frequency frames of the nearshore area [14][15][16]. The video monitoring technique has been proven as a valid tool for measuring wave breaking height because the wave characteristics have a visible signature on the sea surface.…”

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

“…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]. When dealing with coastal ground-based camera systems, with respect to satellite observations, the availability of images with smaller but optimal field-of-view and proper spatial resolution increases the opportunity of removing the barriers related to, for example, cloud cover and temporal lags, facilitating the study of large time series.…”

A New Adaptive Image Interpolation Method to Define the Shoreline at Sub-Pixel Level

“…However, as the most widespread recent mapping techniques are focused on those that minimize acquisition costs, video monitoring and the use of satellite images remain as useful resources for mapping shorelines in planimetry. Video monitoring cameras offer a high temporal resolution and are widely used for coastal research and video-derived coastal indicators [15,16] in a limited space [17][18][19]. Satellite images offer wide geographical coverage with a specific temporal and spatial resolution for each sensor [20,21].…”