6 research outputs found
Detecting animals in African Savanna with UAVs and the crowds
Unmanned aerial vehicles (UAVs) offer new opportunities for wildlife
monitoring, with several advantages over traditional field-based methods. They
have readily been used to count birds, marine mammals and large herbivores in
different environments, tasks which are routinely performed through manual
counting in large collections of images. In this paper, we propose a
semi-automatic system able to detect large mammals in semi-arid Savanna. It
relies on an animal-detection system based on machine learning, trained with
crowd-sourced annotations provided by volunteers who manually interpreted
sub-decimeter resolution color images. The system achieves a high recall rate
and a human operator can then eliminate false detections with limited effort.
Our system provides good perspectives for the development of data-driven
management practices in wildlife conservation. It shows that the detection of
large mammals in semi-arid Savanna can be approached by processing data
provided by standard RGB cameras mounted on affordable fixed wings UAVs
Dolphins in Space: Quantifying the Relative Positions of Bottlenose Dolphins (Tursiops truncatus)
Bottlenose dolphins (Tursiops truncatus) are socially sophisticated mammals with high fission-fusion dynamics and complex communication. The relative positioning of individual dolphins as they swim within their social group may aid in the expression of social roles. This study sought to quantify relative positioning in a small social group of female bottlenose dolphins at the National Aquarium in Baltimore that included two mother-daughter pairs, maternal and paternal half-sisters, a half-aunt and niece, and one unrelated female. We devised a method for scoring relative positioning in three dimensions. We found that the two mothers and their juvenile and adult daughters often swam in pairs, indicating that the mother-offspring relationship continued to be an important affiliation later in life. The two dolphins without a mother or daughter in the group, as well as the youngest juvenile female (one of the daughters), spent more time swimming alone than with others. Both of the mother-daughter pairs frequently swam in a position known as the infant position in the literature, despite the fact that both of the daughters in our group were 8 and 13 years of age. Among frequently associating non-mother/daughter pairs, there was some evidence that one dolphin typically stayed in front of the other, possibly indicating leader/follower roles. Conversely, there was no evidence that any dolphin stayed to the left or right of another; to the inside or outside of another in relation to the pool wall; or above or below another. A discussion of the application of developing technologies, such as machine learning techniques and unmanned aerial vehicles, to future research on relative positioning in cetacean social groups is included
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Whales from space: Assessing the feasibility of using satellite imagery to monitor whales
By the mid-twentieth century, the majority of great whale species were threatened with extinction, following centuries of commercial whaling. Since the implementation of a moratorium on commercial whaling in 1985 by the International Whaling Commission, the recovery of whale population is being regularly assessed. Various methods are used to survey whale populations, though most are spatially limited and prevent remote areas from being studied. Satellites orbiting Earth can access most regions of the planet, offering a potential solution to surveying remote locations. With recent improvements in the spatial resolution of satellite imagery, it is now possible to detect wildlife from space, including whales.
In this thesis, I aimed to further investigate the feasibility of very high resolution (VHR) satellite imagery as a tool to reliably monitor whales. The first objective was to describe, both visually and spectrally, how four morphologically distinct species appear in VHR satellite imagery. The second objective was to explore different ways to automatically detect whales in such imagery, as the current alternative is manual detection, which is time-consuming and impractical when monitoring large areas. With the third objective, I attempted to give some insights on how to estimate the maximum depth at which a whale can be detected in VHR satellite imagery, as this will be crucial to estimate whale abundance from space.
This thesis shows that the four species targeted could be detected with varying degrees of accuracy, some contrasting better with their surroundings. Compared to manual detection, the automated systems trialled here took longer, were not as accurate, and were not transferable to other images, suggesting to focus future automation research on machine learning and the creation of a well-labelled database required to train and validate. The maximum depth of detection could be assessed only approximately using nautical charts. Other methods such as the installation of panels at various depths should be trialled, although it requires prior knowledge of the spectral reflectance of whales above the surface, which I tested on post-mortem samples of whale integument and proved unreliable. Such reflectance should be measured on free-swimming whale using unmanned aerial vehicles or small aircraft. Overall, this thesis shows that currently VHR satellite imagery can be a useful tool to assess the presence or absence of whales, encouraging further developments to make VHR satellite imagery a reliable method to monitor whale numbers.The MAVA Foundation (16035
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Spatio-Temporal Information Extraction Under Uncertainty Using Multi-Source Data Integration and Machine Learning: Applications To Human Settlement Modelling
Due to advances in information and communication technology, new ways of acquisition, storage, and analysis of digital data have emerged. This constitutes new opportunities, but also imposes challenges for many scientific disciplines, including the geospatial sciences, where the availability, accessibility, and spatio-temporal granularity and coverage of environmental, geographic, and socioeconomic data is steadily increasing. Multi-source data measuring identical or related processes typically increase the reliability of knowledge derived but also lead to higher levels of discrepancies. In order to fully benefit from the value of such multi-source data, the contained information needs to be extracted effectively and efficiently, employing adequate data integration, mining, and analysis techniques. This work demonstrates how the integration of coherent multi-source geospatial data supports information extraction and analysis to generate new knowledge of both, the data itself and the underlying phenomenon, exemplified by the spatio-temporal distribution of human settlements. I present three applications in the field of human settlement modelling where data integration is a key component for knowledge acquisition. These three applications consist of i) a deep-learning based classification framework for fully automated extraction of built-up areas from historical maps in the spatial domain, ii) a machine-learning based time series classification framework for estimating changes in built-up areas in the temporal domain, based on multispectral remote sensing time series data, and iii) a novel framework for an in-depth accuracy assessment of model-generated data, exemplified by the Global Human Settlement Layer, for a detailed analysis of data uncertainty in the spatio-temporal domain, as well as across different scales and aggregation levels, attempting to quantify the fitness-for-use of such data.</p
A convolutional neural network for automatic analysis of aerial imagery
This paper introduces a new method to automate the detection of marine species in aerial imagery using a Machine Learning approach. Our proposed system has at its core, a convolutional neural network. We compare this trainable classifier to a handcrafted classifier based on color features, entropy and shape analysis. Experiments demonstrate that the convolutional neural network outperforms the handcrafted solution. We also introduce a negative training example-selection method for situations where the original training set consists of a collection of labeled images in which the objects of interest (positive examples) have been marked by a bounding box. We show that picking random rectangles from the background is not necessarily the best way to generate useful negative examples with respect to learning