6 research outputs found

    Detecting animals in African Savanna with UAVs and the crowds

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    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)

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    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

    A convolutional neural network for automatic analysis of aerial imagery

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    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
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