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Bilge dump detection from SAR imagery using local binary patterns

Author: Mdakane, LW ; Kleynhans, W ; Schwegmann, CP Date: Jul 2015 Accidental or deliberate bilge dumping presents a major threat to the sea ecosystem. We present a semi automatic approach to detect bilge dumping in synthetic aperture radar (SAR) images. The approach consist of three main parts. Firstly, ... Read more
A CA-CFAR and localized wavelet ship detector for sentinel-1 imagery

Author: Schwegmann, CP ; Kleynhans, W ; Salmon, BP ; Mdakane, L Date: Jul 2015 The Maritime Domain Awareness initiative seeks to constantly improve the ways in which maritime information is collected. With the recent release of free Sentinel-1 imagery to the public, monitoring the maritime environment has become a more ... Read more
Detecting settlement expansion in South Africa using a hyper-temporal SAR change detection approach

Author: Kleynhans, W ; Salmon, BP ; Olivier, JC Date: Oct 2015 Recent times have seen a significant increase in the amount of readily available SAR data, with many current and historic SAR data holdings now adopting an open distribution policy. As more regular SAR observations are becoming available, the ... Read more
Feature selection and classification of oil spill from vessels using Sentinel-1 wide–swath synthetic aperture radar data

Author: Mdakane, Lizwe W ; Kleynhans, W Date: Oct 2020 Oil spills are often caused by vessels when dumping oily bilge wastewater at sea (also referred to as bilge dumping). In an synthetic aperture radar (SAR) image, oil spills dampen the radar energy return and appear as linearly shaped dark ... Read more
Hyper-temporal c-band SAR for baseline woody structural assessments in deciduous savannas

Author: Main, Russell S ; Mathieu, Renaud SA ; Kleynhans, W ; Wessels, Konrad J ; Naidoo, Laven ; Asner, GP Date: Aug 2016 Savanna ecosystems and their woody vegetation provide valuable resources and ecosystem services. Locally calibrated and cost effective estimates of these resources are required in order to satisfy commitments to monitor and manage change ... Read more
An image-segmentation-based framework to detect oil slicks from moving vessels in the Southern African oceans using SAR imagery

Author: Mdakane, Lizwe W ; Kleynhans, Waldo Date: Jun 2017 Oil slick events caused due to bilge leakage/dumps from ships and from other anthropogenic sources pose a threat to the aquatic ecosystem and need to be monitored on a regular basis. An automatic image-segmentation-based framework to detect ... Read more
Manifold adaptation for constant false alarm rate ship detection in South African oceans

Author: Schwegmann, CP ; Kleynhans, W ; Salmon, BP Date: Apr 2015 The detection of ships at sea is a difficult task made more so by uncooperative ships, especially when using transponder based ship detection systems. Synthetic Aperture Radar imagery provides a means of observation independent of the ships ... Read more
Medium resolution image fusion, does it enhance forest structure assessment

Author: Roberts, JW ; Van Aardt, J ; Ahmed, FB Date: Jul 2008 This research explored the potential benefits of fusing optical and Synthetic Aperture Radar (SAR) medium resolution satellite-borne sensor data for forest structural assessment. Image fusion was applied as a means of retaining disparate data ... Read more
Monitoring surface deformation associated with groundwater abstraction in the Western Cape using SAR Interferometry

Author: Theron, Andre ; Engelbrecht, Jeanine Date: Oct 2018 Aquifers are able to contain significant amounts of water, which is typically stored in the pore spaces between sand particles or in the fissures and matrix of rocks. This groundwater is an increasingly important source of water in many parts ... Read more
Potential of sinkhole precursor detection through interferometric SAR

Author: Theron, Andre ; Engelbrecht, Jeanine ; Kemp, J Date: Aug 2016 Sinkholes are an unpredictable geohazard that endangers life and structures in susceptible areas globally. Subsidence sinkholes occur above cavernous bedrock comprised of highly soluble evaporates or calcium carbonates such as dolomite or ... Read more
A radar and LiDAR-based earth observation system for monitoring savanna woody structure in southern Africa

Author: Mathieu, Renaud ; Wessels, Konrad ; Main, Russell S ; Naidoo, Laven ; Van der Bergh, Frans ; Erasmus, Barend Date: Apr 2018 In southern Africa, landscapes are dominated by savannas, i.e., mixed tree-grass communities. These savannas are threatened by land clearing and degradation, as well as the densification of woody plants, a process known as bush encroachment. ... Read more
Satellite synthetic aperture radar for monitoring of surface deformation in shallow underground mining environments

Author: Engelbrecht, Jeanine ; Inggs, MR Date: Aug 2016 Surface deformations associated with shallow underground mining activities have significant implications for both the natural- and built environment. Environmental problems include the exacerbation of acid mine drainage and the alteration of ... Read more
Savannah woody structure modelling and mapping using multifrequency (X-, C- and L-band) synthetic aperture radar data

Author: Naidoo, Laven ; Mathieu, Renaud SA ; Main, Russell S ; Kleynhans, W ; Wessels, Konrad J ; Asner, G ; Leblon, B Date: Jul 2015 Structural parameters of the woody component in African savannahs provide estimates of carbon stocks that are vital to the understanding of fuelwood reserves, which is the primary source of energy for 90% of households in South Africa (80% ... Read more
SENTINEL-1 SAR for operational monitoring of Southern Africa Oceans

Author: Mdakane, Lizwe W Date: Jun 2022 The introduction of Synthetic Aperture Radar (SAR) through the Oceans and Coasts Monitoring Information system (OCIMS) has therefore become a critical tool for operational coastal and ocean monitoring in South Africa. Natural/man-made ocean ... Read more
Ship detection in Sentinel-1 imagery using the h-dome transformation

Author: Schwegmann, CP ; Kleynhans, W ; Salmon, BP ; Mdakane, L Date: Jul 2015 The ability to reliably detect ships within the ocean is one of the core capabilities of Maritime Domain Awareness. Constant improvements are pursued in both computational speed and reliable responses to events by exploring new ship detection ... Read more
Ship detection in South African oceans using a combination of SAR and historic LRIT data

Author: Kleynhans, W ; Salmon, BP ; Schwegmann, CP ; Seotlo, MV Date: Jul 2013 Regular surveillance of territorial sea areas is increasingly important for coastal nations as these marine areas are a valuable economic resource (e.g. for fisheries or oil extraction). The responsibility for the administration, law enforcement, ... Read more
Simulated annealing CFAR threshold selection for South African ship detection in ASAR imagery

Author: Schwegmann, CP ; Kleynhans, W ; Salmon, BP Date: Jul 2014 Synthetic Aperture Radar images are able to detect ships that would be hidden to tradition ship tracking methods due to their transponders being turned off. Using a SAR image as input, the CFAR method can highlight these ships given a correctly ... Read more
Small ships don't shine: classification of ocean vessels from low resolution, large swath area SAR acquisitions

Author: Meyer, Rory GV ; Kleynhans, Waldo ; Schwegmann, Colin P Date: Jul 2016 Monitoring ocean vessels that are not near the coast is difficult and expensive. One way of overcoming this is through the use of SAR satellite platforms. To monitor the largest possible area would require the use of course resolution SAR ... Read more
Using an active contour method to detect bilge dumps from SAR imagery

Author: Mdakane, Lizwe W ; Kleynhans, Waldo ; Schwegmann, Colin P Date: Jul 2016 An automatic approach to detect bilge dumping in synthetic aperture radar (SAR) images over Southern African oceans is proposed. The approach uses a threshold-based algorithm and a region-based active contour model (ACM) algorithm to achieve ... Read more
Woody savannah tree structural assessment in the greater Kruger National Park region, South Africa, using multi-seasonal polarimetric synthetic aperture radar (SAR) and optical data product approaches

Author: Naidoo, Laven ; Mathieu, Renaud SA ; Cho, Moses A ; Main, Russell S ; Asner, G Date: Nov 2012 With a mean net primary productivity of 7.2 tC/ha/year and a minimum woody coverage ranging from 10 to 30%, savannahs account for approximately 40% of the global carbon store. The savannah woody component impacts the fire regime, biomass ... Read more

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