References of "Linchant, Julie"
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See detailPotentiel des véhicules aériens sans pilote dans la détection des activités humaines illégales dans les aires protégées en République Démocratique du Congo
Semeki Ngabinzeke, Jean; Linchant, Julie ULg; Quevauvillers, Samuel ULg et al

in Journal of Unmanned Vehicle Systems (2016), 4

The recent advent of unmanned aerial vehicles (UAVs) in natural resource management opens new opportunities to help protected area managers fighting against various human pressures. The Falcon UAV was ... [more ▼]

The recent advent of unmanned aerial vehicles (UAVs) in natural resource management opens new opportunities to help protected area managers fighting against various human pressures. The Falcon UAV was used for 15 missions to help detect human activities in Garamba National Park and its surrounding game reserves (Gangala na Bodio, Mondo Missa) in the North-Eastern Democratic Republic of Congo. A Sony Block camera coupled with a Tamarisk thermal camera was used to record videos, whereas photos were acquired with a Sony Nex7 digital camera. Tests showed that it was possible to detect precise objects using the Falcon UAV. Houses, fields, bare ground patches, burned areas, roads and tracks were easily detectable and identified in the videos at a flight altitude of up to 250 m AGL. Artisanal gold mining sites (size ≤ 0.21 ha) are also recognizable on the video and still images. Improvements are needed, notably in photo overlap and georeferencing, but the system shows great potential to ensure detection and continuous surveillance of human activities within protected areas. [less ▲]

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See detailCartographie de la dynamique de terroirs villageois à l'aide d'un drone dans les aires protégées de la République Démocratique du Congo
Semeki Ngabinzeke, Jean; Linchant, Julie ULg; Quevauvillers, Samuel ULg et al

in Bois et Forêts des Tropiques (2016), 330(4), 69-83

Les aires protégées de la République démocratique du Congo (RDC) sont menacées par diverses pressions anthropiques nécessitant un suivi fréquent et précis. Le mini-drone Falcon équipé d’un appareil photo ... [more ▼]

Les aires protégées de la République démocratique du Congo (RDC) sont menacées par diverses pressions anthropiques nécessitant un suivi fréquent et précis. Le mini-drone Falcon équipé d’un appareil photo numérique Sony NEX-7 a été utilisé pour cartographier et suivre la dynamique d’un terroir villageois dans le Domaine de chasse de Mondo Missa à l’est du Parc national de la Garamba, au nord-est de la RDC. Un total de 3 143 photos acquises en avril et juillet 2015, avec une résolution au sol de 8 cm/pixel, a été orthorectifié. La cartographie a porté sur une zone de 114 ha. Les ortho-images ont d’abord été segmentées, les segments étant ensuite classés manuellement par photo-interprétation. Des changements notables ont été constatés entre les deux dates. Les zones des forêts et savanes ont perdu 6,5 ha (86,6 à 80,1 ha). Les jachères sont passées de 16,9 à 8,2 ha, les défriches de 4,1 à 10,0 ha. Les cultures saisonnières ont connu une variation allant de 3,2 à 11,8 ha. La taille moyenne des parcelles cultivées est de 0,2 ha (s = 0,14 ha ; n = 50). Enfin, la surface occupée par les arbres isolés a peu évolué (de 1,3 à 1,9 ha), celle des implantations humaines étant constante (1,7 ha). Ces résultats traduisent le fait que l’expansion de l’agriculture itinérante sur brûlis induit une conversion des habitats naturels et une modification de la composition végétale. Les aéronefs sans pilote à bord permettent de réaliser une cartographie précise et une surveillance rapide des changements d’affectation des terres à petite échelle dans les aires protégées des forêts et savanes tropicales. Ils offrent donc une solution efficace pour évaluer la déforestation et la dégradation au sein des espaces occupés par les communautés locales. Cette évaluation représente un enjeu important dans le processus REDD+ qui envisage de quantifier avec précision ces évolutions. [less ▲]

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See detailWiMUAS: New inventory method to perform wildlife counts with UAS and review the large datasets
Linchant, Julie ULg; Lhoest, Simon ULg; Semeki, Jean et al

Conference (2015, October 13)

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See detailHow Many Hippos (HOMHIP): Algorithm for automatic counts of animals with infrared thermal imagery from UAV
Lhoest, Simon ULg; Linchant, Julie ULg; Quevauvillers, Samuel ULg et al

Conference (2015, October 02)

The common hippopotamus (Hippopotamus amphibius L.) is part of the animal species endangered because of multiple human pressures. Monitoring of species for conservation is then essential, and the ... [more ▼]

The common hippopotamus (Hippopotamus amphibius L.) is part of the animal species endangered because of multiple human pressures. Monitoring of species for conservation is then essential, and the development of census protocols has to be chased. UAV technology is considering as one of the new perspectives for wildlife survey. Indeed, this technique has many advantages but its main drawback is the generation of a huge amount of data to handle. This study aims at developing an algorithm for automatic count of hippos, by exploiting thermal infrared aerial images acquired from UAV. This attempt is the first known for automatic detection of this species. Images taken at several flight heights can be used as inputs of the algorithm, ranging from 38 to 155 meters above ground level. A Graphical User Interface has been created in order to facilitate the use of the application. Three categories of animals have been defined following their position in water. The mean error of automatic counts compared with manual delineations is +2.3% and shows that the estimation is unbiased. Those results show great perspectives for the use of the algorithm in populations monitoring after some technical improvements and the elaboration of statistically robust inventories protocols. [less ▲]

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See detailWiMUAS: A tool to review wildlife data from various flight plans
Linchant, Julie ULg; Lhoest, Simon ULg; Quevauvillers, Samuel ULg et al

Conference (2015, October 02)

To get around UAS limitations and propose a viable solution for wildlife monitoring, the development of new inventory methods is needed. However, most authors use the classic systematic transect method as ... [more ▼]

To get around UAS limitations and propose a viable solution for wildlife monitoring, the development of new inventory methods is needed. However, most authors use the classic systematic transect method as data processing and statistics are easier. We thus created an application to process data from every type of flight plan and to help detect and compare observations on large datasets. WiMUAS is a small software compatible with the open-source QGIS© that allows the creation of visual maps compatible with geographical information systems based on telemetry data and payload parameters to estimate the covered area. The application also has a slider for animal detection that allows multiple observers to record and compare their results for accurate counts. We then tested it on data from a trial realized on savannah animal populations in Democratic Republic of Congo using the Falcon UAS. We created a new type of flight plan, a rosette-shaped design that can be covered in three flights,.and repeated it twice. More than 5000 images were collected during the six flights. Image projection gives an area of 12,4 km2 for the first trial and of 12,1 km2 for the second. The mean sampling rate for both test is 6,1 %. Observers spotted buffaloes, hippos, warthogs and various antelopes with different success over an average rate of 8 images reviewed per minute. Resulting densities observed by the three observers are similar for each test (coefficient of variation 6,9 and 8,6 % respectively) but mean densities vary a lot between the two trials (23,8 and 6,5 animals/km2 respectively). [less ▲]

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See detailAre unmanned aircraft systems (UASs) the future of wildlife monitoring? A review of accomplishments and challenges
Linchant, Julie ULg; Lisein, Jonathan ULg; Semeki, Jean et al

in Mammal Review (2015), 45

1. Regular monitoring of animal populations must be established to ensure wildlife protection, especially when pressure on animals is high. The recent development of drones or unmanned aircraft systems ... [more ▼]

1. Regular monitoring of animal populations must be established to ensure wildlife protection, especially when pressure on animals is high. The recent development of drones or unmanned aircraft systems (UASs) opens new opportunities. UASs have several advantages, including providing data at high spatial and temporal resolution, providing systematic, permanent data, having low operational costs and being low-risk for the operators. However, UASs have some constraints, such as short flight endurance. 2. We reviewed studies in which wildlife populations were monitored by using drones, described accomplishments to date and evaluated the range of possibilities UASs offer to provide new perspectives in future research. 3. We focused on four main topics: 1) the available systems and sensors; 2) the types of survey plan and detection possibilities; 3) contributions towards antipoaching surveillance; and 4) legislation and ethics. 4. We found that small fixed-wing UASs are most commonly used because these aircraft provide a viable compromise between price, logistics and flight endurance. The sensors are typically electro-optic or infrared cameras, but there is the potential to develop and test new sensors. 5. Despite various flight plan possibilities, mostly classical line transects have been employed, and it would be of great interest to test new methods to adapt to the limitations of UASs. Detection of many species is possible, but statistical approaches are unavailable if valid inventories of large mammals are the purpose. 6. Contributions of UASs to anti-poaching surveillance are not yet well documented in the scientific literature, but initial studies indicate that this approach could make important contributions to conservation in the next few years. 7. Finally, we conclude that one of the main factors impeding the use of UASs is legislation. Restrictions in the use of airspace prevent researchers from testing all possibilities, and adaptations to the relevant legislation will be necessary in future. [less ▲]

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See detailHOW MANY HIPPOS (HOMHIP): Algorithm for automatic counts of animals with infra-red thermal imagery from UAV
Lhoest, Simon ULg; Linchant, Julie ULg; Quevauvillers, Samuel ULg et al

in International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences (2015), XL-3/W3

The common hippopotamus (Hippopotamus amphibius L.) is part of the animal species endangered because of multiple human pressures. Monitoring of species for conservation is then essential, and the ... [more ▼]

The common hippopotamus (Hippopotamus amphibius L.) is part of the animal species endangered because of multiple human pressures. Monitoring of species for conservation is then essential, and the development of census protocols has to be chased. UAV technology is considering as one of the new perspectives for wildlife survey. Indeed, this technique has many advantages but its main drawback is the generation of a huge amount of data to handle. This study aims at developing an algorithm for automatic count of hippos, by exploiting thermal infrared aerial images acquired from UAV. This attempt is the first known for automatic detection of this species. Images taken at several flight heights can be used as inputs of the algorithm, ranging from 38 to 155 meters above ground level. A Graphical User Interface has been created in order to facilitate the use of the application. Three categories of animals have been defined following their position in water. The mean error of automatic counts compared with manual delineations is +2.3% and shows that the estimation is unbiased. Those results show great perspectives for the use of the algorithm in populations monitoring after some technical improvements and the elaboration of statistically robust inventories protocols. [less ▲]

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See detailWIMUAS: Developing a tool to review wildlife data from various UAS flight plans
Linchant, Julie ULg; Lhoest, Simon ULg; Quevauvillers, Samuel ULg et al

in International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences (2015), XL-3/W3

To get around UAS limitations and propose a viable solution for wildlife monitoring, the development of new inventory methods is needed. However, most authors use the classic systematic transect method as ... [more ▼]

To get around UAS limitations and propose a viable solution for wildlife monitoring, the development of new inventory methods is needed. However, most authors use the classic systematic transect method as data processing and statistics are easier. We thus created an application to process data from every type of flight plan and to help detect and compare observations on large datasets. WiMUAS is a small software compatible with the open-source QGIS© that allows the creation of visual maps compatible with geographical information systems based on telemetry data and payload parameters to estimate the covered area. The application also has a slider for animal detection that allows multiple observers to record and compare their results for accurate counts. We then tested it on data from a trial realized on savannah animal populations in Democratic Republic of Congo using the Falcon UAS. We created a new type of flight plan, a rosette-shaped design that can be covered in three flights,.and repeated it twice. More than 5000 images were collected during the six flights. Image projection gives an area of 12,4 km2 for the first trial and of 12,1 km2 for the second. The mean sampling rate for both test is 6,1 %. Observers spotted buffaloes, hippos, warthogs and various antelopes with different success over an average rate of 8 images reviewed per minute. Resulting densities observed by the three observers are similar for each test (coefficient of variation 6,9 and 8,6 % respectively) but mean densities vary a lot between the two trials (23,8 and 6,5 animals/km2 respectively). [less ▲]

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See detailNew technologies in conservation: monitoring African wildlife with UAS
Linchant, Julie ULg; Semeki, Jean; Lejeune, Philippe ULg et al

Conference (2014, December 13)

In the vast protected areas of Africa, traditional wildlife surveys performed by plane or foot are logistically difficult to implement due to the lack of means and appropriate materials. Moreover, the ... [more ▼]

In the vast protected areas of Africa, traditional wildlife surveys performed by plane or foot are logistically difficult to implement due to the lack of means and appropriate materials. Moreover, the possibilities of encountering poachers in the field pose a serious risk to the monitoring teams. Over the last decade, civilian UAS (Unmanned Aerial Systems) boomed in natural resource monitoring. One of the biggest challenges of the UAS is to replace traditional wildlife censuses for the application of wildlife conservation. Parameters have to be approached in a different way than before. We performed test flights in the open savannah of the Garamba National Park during the wet season using the Falcon Unmanned UAS. Both photos (Sony Nex7, 24Mp) and videos, including thermal infrared videos (Tamarisk 640x480), have been used. Flight altitude ranged from 50 to 200m and pictures showed that animals can be effectively detected at 100m. We spotted elephants, hippopotamus and buffaloes as well as other smaller species such as hartebeests, kobs and warthogs. Thermal videos gave medium quality results during the day due to the heat but performed well during the night. The limited range and endurance of the UAS suggest a rethink of the usual census protocols. We therefore tested new flight plans in a rosette shape to take advantage of the higher points in the park, with transects having the length of the maximal range. Twelve transects of 10km can be covered in half a day with pictures covering a 15.6km² area. Human activities could also be detected. Pictures showed areas burned by poachers and the thermal infrared camera allows the detection of fires from a high altitude. Future developments need to be investigated such as automatic detection to review the huge amount of data collected and statistical methods must be adapted to those challenging situations. [less ▲]

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See detailLe continent des couleurs
Dumortier, Tanguy; Vermeulen, Cédric ULg; Linchant, Julie ULg

Diverse speeche and writing (2014)

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See detailHow to survey your hippos night and day? Follow them in bed with drones!
Linchant, Julie ULg; Lejeune, Philippe ULg; Vermeulen, Cédric ULg

Scientific conference (2014, October 20)

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See detailConservation et biodiversité animale en Afrique centrale
Vermeulen, Cédric ULg; Linchant, Julie ULg

in Delvingt, Willy; Vermeulen, Cédric; Lebrun, Philippe (Eds.) et al La recherche dans les aires protégées d'Afrique centrale. Parcs et Réserves 69 (3). (2014)

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See detailLes drones au secours de la grande faune menacée de RDC
Linchant, Julie ULg; Lejeune, Philippe ULg; Vermeulen, Cédric ULg

in Parcs et Réserves (2014), 69(3), 5-13

Dans un contexte international de pressions de plus en plus intenses sur la faune sauvage, caractérisées notamment par une recrudescence intense du braconnage, le suivi régulier de la faune est essentiel ... [more ▼]

Dans un contexte international de pressions de plus en plus intenses sur la faune sauvage, caractérisées notamment par une recrudescence intense du braconnage, le suivi régulier de la faune est essentiel pour assurer sa conservation. La situation de la biodiversité en République Démocratique du Congo est particulièrement préoccupante suite aux nombreux conflits armés et aux pressions anthropiques qui en découlent, ainsi qu’au manque de moyens et d’investissement. Habituellement, le suivi de la faune est réalisé à l’aide d’inventaires pédestres et aériens. Cependant, ces méthodes font face à de nombreuses contraintes, notamment leur coût et la logistique importante qu’elles demandent. Elles sont aussi dangereuses pour les opérateurs, ces derniers risquant leur vie lors d’accidents de vol ou lors de rencontres avec des braconniers ou des animaux potentiellement dangereux. Dans ce contexte, l’utilisation des drones civils, actuellement en pleine expansion, représente une alternative aux méthodes classiques pour le suivi de la grande faune et la surveillance des aires protégées. En effet, cette nouvelle technologie présente un coût plus faible, une logistique facile et une prise en main rapide, ainsi qu’un minimum de risque pour les opérateurs. Néanmoins, elle en est à ses balbutiements et de nouvelles méthodes de suivi doivent être mises au point pour relever le défi imposé par les contraintes liées à ce matériel innovant, tels que la faible autonomie et le traitement de grands volumes de données. L’Université de Liège-Gembloux Agro-Bio Tech a bâti, en partenariat avec le CIFOR, le projet WiMUAS visant à développer ces nouvelles méthodes dans le cadre des aires protégées en RDC. Cet article s’appuie sur une revue bibliographique récente pour en présenter les trois principaux objectifs en regard des développements existants : - (i) la mise au point de nouvelles méthodes d’inventaire et de suivis ponctuels de la grande faune par analyse d’images et de vidéos obtenues par drone ; - (ii) la gestion des périphéries et activités illégales notamment grâce à la cartographie précise de ces activités qui peut être obtenue via l’imagerie drone ; - (iii) la lutte anti-braconnage qui pourrait être appuyée par une reconnaissance du terrain par drone pour rechercher et fournir des indices en limitant la mise en danger des gardes. [less ▲]

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See detailAerial surveys using an Unmanned Aerial System (UAS): comparison of different methods for estimating the surface area of sampling strips
Lisein, Jonathan ULg; Linchant, Julie ULg; Lejeune, Philippe ULg et al

in Tropical Conservation Science (2013), 6(4), 506-520

Conservation of natural ecosystems requires regular monitoring of biodiversity, including the estimation of wildlife density. Recently, unmanned aerial systems (UAS) have become more available for ... [more ▼]

Conservation of natural ecosystems requires regular monitoring of biodiversity, including the estimation of wildlife density. Recently, unmanned aerial systems (UAS) have become more available for numerous civilian applications. The use of small drones for wildlife surveys as a surrogate for manned aerial surveys is becoming increasingly attractive and has already been implemented with some success. This raises the question of how to process UAS imagery in order to determine the surface area of sampling strips within an acceptable confidence level. For the purpose of wildlife surveys, the estimation of sampling strip surface area needs to be both accurate and quick, and easy to implement. As GPS and an inertial measurement units are commonly integrated within unmanned aircraft platforms, two methods of direct georeferencing were compared here. On the one hand, we used the image footprint projection (IFP) method, which utilizes collinearity equations on each image individually. On the other hand, the Structure from Motion (SfM) technique was used for block orientation and georeferencing. These two methods were compared on eight sampling strips. An absolute orientation of the strip was determined by indirect georeferencing using ground control points. This absolute orientation was considered as the reference and was used for validating the other two methods. The IFP method was demonstrated to be the most accurate and the easiest to implement. It was also found to be less demanding in terms of image quality and overlap. However, even though a flat landscape is the type most widely encountered in wildlife surveys in Africa, we recommend estimating IFP sensitivity at an accentuation of the relief. [less ▲]

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See detailUsing drones to count the elephants: a new approach of wildlife inventories
Linchant, Julie ULg; Vermeulen, Cédric ULg; Lisein, Jonathan ULg et al

Conference (2013, August 29)

The use of UASs (Unmanned Aerial Systems) in wildlife survey is still recent but the fast development of this technology shows great possibilities and it could soon become an inevitable tool in wildlife ... [more ▼]

The use of UASs (Unmanned Aerial Systems) in wildlife survey is still recent but the fast development of this technology shows great possibilities and it could soon become an inevitable tool in wildlife management. The purpose of this study was to test the feasibility of inventories by UAS to survey large mammals in the Nazinga Game Ranch in the south of Burkina Faso. The Gatewing X100TM equipped with a Ricoh GR III camera was used to test the animal reaction as it passed, and their visibility on the images. A set of more than 7000 images was collected and observations revealed that only elephants (Loxodonta africana) were easily visible while medium and small sized mammals were not. At a height of 100 m the easy observation of elephant allows experts to enumerate them on images and no reaction was recorded as the UAS passed. We therefore implemented an aerial strip sample count along transects used for the annual wildlife foot count. A total of 34 elephants has been recorded on 4 transects, each overflown twice. The elephant density was estimated at 2.47 elephants/km2 with a coefficient of variation (CV%) of 36.10 %. UAS inventory of elephants is promising but improvements need to be done. The main drawback of our UAS was its autonomy. If we wish to replace manned aircraft survey of large areas (about 1000 km of transect per day vs 40 km for our UAS), increased endurance of small UAS is a requirement and the monitoring strategy should be adapted according to the sampling plan. Also, the UAS is as expensive as a second-hand light aircraft. However the logistic and flight implementation are easier, the running costs are lower and its use is safer. With technological evolution making civil UASs more efficient, they will be able to compete with light aircrafts for aerial wildlife surveys. [less ▲]

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