Megan Winsen

Ms. Megan Winsen

orcid

Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 February 2021 in Methods in Ecology and Evolution
Verified
Journal Article
Closed access
PDF file
ECEvangeline Corcoran
Evangeline Corcoran
MWMegan Winsen
Megan Winsen
ASAshlee Sudholz
Ashlee Sudholz
GHGrant Hamilton
Grant Hamilton
MWMegan Winsen
Megan Winsen

19 May 2022 in Remote Sensing
Verified
Journal Article
Open access
PDF file
MWMegan Winsen
Megan Winsen
SDSimon Denman
Simon Denman
ECEvangeline Corcoran
Evangeline Corcoran
GHGrant Hamilton
Grant Hamilton
Effective management of threatened and invasive species requires regular and reliable population estimates. Drones are increasingly utilised by ecologists for this purpose as they are relatively inexpensive. They enable larger areas to be surveyed than traditional methods for many species, particularly cryptic species such as koalas, with less disturbance. The development of robust and accurate methods for species detection is required to effectively use the large volumes of data generated by this survey method. The enhanced predictive and computational power of deep learning ensembles represents a considerable opportunity to the ecological community. In this study, we investigate the potential of deep learning ensembles built from multiple convolutional neural networks (CNNs) to detect koalas from low-altitude, drone-derived thermal data. The approach uses ensembles of detectors built from combinations of YOLOv5 and models from Detectron2. The ensembles achieved a strong balance between probability of detection and precision when tested on ground-truth data from radio-collared koalas. Our results also showed that greater diversity in ensemble composition can enhance overall performance. We found the main impediment to higher precision was false positives but expect these will continue to reduce as tools for geolocating detections are improved. The ability to construct ensembles of different sizes will allow for improved alignment between the algorithms used and the characteristics of different ecological problems. Ensembles are efficient and accurate and can be scaled to suit different settings, platforms and hardware availability, making them capable of adaption for novel applications.

21 March 2023 in Remote Sensing
Verified
Journal Article
Open access
PDF file
MWMegan Winsen
Megan Winsen
GHGrant Hamilton
Grant Hamilton
Light detection and ranging (LiDAR) has been a tool of choice for 3D dense point cloud reconstructions of forest canopy over the past two decades, but advances in computer vision techniques, such as structure from motion (SfM) photogrammetry, have transformed 2D digital aerial imagery into a powerful, inexpensive and highly available alternative. Canopy modelling is complex and affected by a wide range of inputs. While studies have found dense point cloud reconstructions to be accurate, there is no standard approach to comparing outputs or assessing accuracy. Modelling is particularly challenging in native eucalypt forests, where the canopy displays abrupt vertical changes and highly varied relief. This study first investigated whether a remotely sensed LiDAR dense point cloud reconstruction of a native eucalypt forest completely reproduced canopy cover and accurately predicted tree heights. A further comparison was made with a photogrammetric reconstruction based solely on near-infrared (NIR) imagery to gain some insight into the contribution of the NIR spectral band to the 3D SfM reconstruction of native dry eucalypt open forest. The reconstructions did not produce comparable canopy height models and neither reconstruction completely reproduced canopy cover nor accurately predicted tree heights. Nonetheless, the LiDAR product was more representative of the eucalypt canopy than SfM-NIR. The SfM-NIR results were strongly affected by an absence of data in many locations, which was related to low canopy penetration by the passive optical sensor and sub-optimal feature matching in the photogrammetric pre-processing pipeline. To further investigate the contribution of NIR, future studies could combine NIR imagery captured at multiple solar elevations. A variety of photogrammetric pre-processing settings should continue to be explored in an effort to optimise image feature matching.

6 February 2025 in Remote Sensing
Verified
Journal Article
Open access
PDF file
Pirunthan KeerthinathanPirunthan Keerthinathan
Pirunthan Keerthinathan
MWMegan Winsen
Megan Winsen
TKThanirosan Krishnakumar
Thanirosan Krishnakumar
Anthony AriyanayagamAnthony Ariyanayagam
Anthony Ariyanayagam
GHGrant Hamilton
Grant Hamilton
FGFelipe Gonzalez
Felipe Gonzalez
Vegetation characteristics significantly influence the impact of wildfires on individual building structures, and these effects can be systematically analyzed using heat transfer modelling software. Close-range light detection and ranging (LiDAR) data obtained from uncrewed aerial systems (UASs) capture detailed vegetation morphology; however, the integration of dense vegetation and merged canopies into three-dimensional (3D) models for fire modelling software poses significant challenges. This study proposes a method for integrating the UAS–LiDAR-derived geometric features of vegetation components—such as bark, wooden core, and foliage—into heat transfer models. The data were collected from the natural woodland surrounding an elevated building in Samford, Queensland, Australia. Aboveground biomass (AGB) was estimated for 21 trees utilizing three 3D tree reconstruction tools, with validation against biomass allometric equations (BAEs) derived from field measurements. The most accurate reconstruction tool produced a tree mesh utilized for modelling vegetation geometry. A proof of concept was established with Eucalyptus siderophloia, incorporating vegetation data into heat transfer models. This non-destructive framework leverages available technologies to create reliable 3D tree reconstructions of complex vegetation in wildland–urban interfaces (WUIs). It facilitates realistic wildfire risk assessments by providing accurate heat flux estimations, which are critical for evaluating building safety during fire events, while addressing the limitations associated with direct measurements.

1 October 2026 in Basic and Applied Ecology
Verified
Journal Article
Open access
MWMegan Winsen
Megan Winsen
CCCarly Campbell
Carly Campbell
GHGrant Hamilton
Grant Hamilton

28 August 2026 in Ecology and Evolution
Verified
Journal Article
Open access
MWMegan Winsen
Megan Winsen
SDSimon Denman
Simon Denman
GHGreg Hocking
Greg Hocking
GHGrant Hamilton
Grant Hamilton
While ecologists are exploring the capacity of artificial intelligence to automatically identify wildlife in camera trap and other remote sensing data, it has yet to be commonly adopted in workflows that produce density or abundance estimates and thus many image datasets remain under‐analysed. There is potential to enhance image classification with deep learning ensembles which remain uncommon in wildlife studies, and to synergistically connect the output with population modelling in automated workflows. Here we present a repeatable workflow that connects these elements in a case study of macropods (Bennett's wallaby Notamacropus rufogriseus and Tasmanian pademelon Thylogale billardierii ) in Tasmania, Australia. We analysed a pre‐existing camera trap dataset with no contemporaneous field‐collected data. We used readily available computer vision algorithms to train a deep learning ensemble to classify the most common fauna in the dataset, achieving an overall classification accuracy of 94%. Once reviewed, we connected the output to a hierarchical abundance estimation process via a fully scripted workflow designed for repeat application, including the derivation of covariate data from spatial proxies. We then tested the use of classification confidence levels to subset raw (unverified) automated detections, by replacing the verified detection history with a series of automatically generated versions. We found that a detection history derived from a confidence level of 0.75 produced a highly comparable abundance estimate. Our analysis suggested that correctly identifying empty sampling occasions was more important to the estimation process than correctly identifying all occasions with detections. The potential to feed automated detection output that is subset with a classification confidence threshold into a modelling workflow, in place of costly manual verification, represents a high yield opportunity that is worthy of further investigation. In addition, our ensemble approach provides a tool for ecologists who study underrepresented fauna that occur in less frequently surveyed locations and habitats.