Unmanned Aerial Vehicles (UAVs) in environmental biology: A Review

Acquiring information about the environment is a key step during each study in the field of environmental biology at different levels, from an individual species to community and biome. However, obtaining information about the environment is frequently difficult because of, for example, the phenological timing, spatial distribution of a species or limited accessibility of a particular area for the field survey. Moreover, remote sensing technology, which enables the observation of the Earth’s surface and is currently very common in environmental research, has many limitations such as insufficient spatial, spectral and temporal resolution and a high cost of data acquisition. Since the 1990s, researchers have been exploring the potential of different types of unmanned aerial vehicles (UAVs) for monitoring Earth’s surface. The present study reviews recent scientific literature dealing with the use of UAV in environmental biology. Amongst numerous papers, short communications and conference abstracts, we selected 110 original studies of how UAVs can be used in environmental biology and which organisms can be studied in this manner. Most of these studies concerned the use of UAV to measure the vegetation parameters such as crown height, volume, number of individuals (14 studies) and quantification of the spatio-temporal dynamics of vegetation changes (12 studies). UAVs were also frequently applied to count birds and mammals, especially those living in the water. Generally, the analytical part of the present study was divided into following sections: (1) detecting, assessing and predicting threats on vegetation, (2) measuring the biophysical parameters of vegetation, (3) quantifying the dynamics of changes in plants and habitats and (4) population and behaviour studies of animals. At the end, we also synthesised all the information showing, amongst others, the advances in environmental biology because of UAV application. Considering that 33% of studies found and included in this review were published in 2017 and 2018, it is expected that the number and variety of applications of UAVs in environmental biology will increase in the future

Autonomous monitoring framework for resource-constrained environments

Acknowledgments The research described here is supported by the award made by the RCUK Digital Economy programme to the dot.rural Digital Economy Hub, reference: EP/G066051/1. URL: http://www.dotrural.ac.uk/RemoteStream/Peer reviewedPublisher PD

Sensitive and specific detection of E. coli using biomimetic receptors in combination with a modified heat-transfer method

We report on a novel biomimetic sensor that allows sensitive and specific detection of Escherichia colt (E. coli) bacteria in a broad concentration range from 10(2) up to 10(6) CFU/mL in both buffer fluids and relevant food samples (i.e. apple juice). The receptors are surface-imprinted polyurethane layers deposited on stainless-steel chips. Regarding the transducer principle, the sensor measures the increase in thermal resistance between the chip and the liquid due to the presence of bacteria captured on the receptor surface. The low noise level that enables the low detection limit originates from a planar meander element that serves as both a heater and a temperature sensor. Furthermore, the experiments show that the presence of bacteria in a liquid enhances the thermal conductivity of the liquid itself. Reference tests with a set of other representative species of Enterobacteriaceae, closely related to E. coli, indicate a very low cross-sensitivity with a sensor response at or below the noise level

Migrating eastern North Pacific gray whale call and blow rates estimated from acoustic recordings, infrared camera video, and visual sightings.

During the eastern North Pacific gray whale 2014-2015 southbound migration, acoustic call recordings, infrared blow detections, and visual sightings were combined to estimate cue rates, needed to convert detections into abundance. The gray whale acoustic call rate ranged from 2.3-24 calls/whale/day during the peak of the southbound migration with an average of 7.5 calls/whale/day over both the southbound and northbound migrations. The average daily calling rate increased between 30 December-13 February. With a call rate model, we estimated that 4,340 gray whales migrated south before visual observations began on 30 December, which is 2,829 more gray whales than used in the visual estimate, and would add approximately 10% to the abundance estimate. We suggest that visual observers increase their survey effort to all of December to document gray whale presence. The infrared camera blow rate averaged 49 blows/whale/hour over 5-8 January. Probability of detection of a whale blow by the infrared camera was the same at night as during the day. However, probability of detection decreased beyond 2.1 km offshore, whereas visual sightings revealed consistent whale densities up to 3 km offshore. We suggest that future infrared camera surveys use multiple cameras optimised for different ranges offshore

Multistage, multiband and sequential imagery to identify and quantify non-forest vegetation resources

Earth Resources photographs from Apollo 6, 7, and 9 and photographs taken during Gemini 4, were used in the research along with high altitude and conventional aerial photography. A unified land use and resource analysis system was devised and used to develop a mapping legend. The natural vegetation, land use, macrorelief, and landforms of northern Maricopa County, Arizona, were analyzed and inventoried. This inventory was interpreted in relation to the critical problem of urban expansion and agricultural production in the study area. The central thrust of the research program has been to develop methods for use of space and small-scale, high-altitude aerial photography to develop information for land use planning and resource allocation decisions

무인비행체 탑재 열화상 및 실화상 이미지를 활용한 야생동물 탐지 가능성 연구

학위논문(석사) -- 서울대학교대학원 : 환경대학원 환경조경학과, 2022.2. 송영근.야생동물의 탐지와 모니터링을 위해, 현장 직접 관찰, 포획-재포획과 같은 전통적 조사 방법이 다양한 목적으로 수행되어왔다. 하지만, 이러한 방법들은 많은 시간과 상대적으로 비싼 비용이 필요하며, 신뢰 가능한 탐지 결과를 얻기 위해선 숙련된 현장 전문가가 필요하다. 게다가, 전통적인 현장 조사 방법은 현장에서 야생동물을 마주치는 등 위험한 상황에 처할 수 있다. 이에 따라, 카메라 트래핑, GPS 추적, eDNA 샘플링과 같은 원격 조사 방법이 기존의 전통적 조사방법을 대체하며 더욱 빈번히 사용되기 시작했다. 하지만, 이러한 방법들은 여전히 목표로 하는 대상의 전체 면적과, 개별 개체를 탐지할 수 없다는 한계를 가지고 있다. 이러한 한계를 극복하기 위해, 무인비행체 (UAV, Unmanned Aerial Vehicle)가 야생동물 탐지의 대중적인 도구로 자리매김하고 있다. UAV의 가장 큰 장점은, 선명하고 촘촘한 공간 및 시간해상도와 함께 전체 연구 지역에 대한 동물 탐지가 가능하다는 것이다. 이에 더해, UAV를 사용함으로써, 접근하기 어려운 지역이나 위험한 곳에 대한 조사가 가능해진다. 하지만, 이러한 이점 외에, UAV의 단점도 명확히 존재한다. 대상지, 비행 속도 및 높이 등과 같이 UAV를 사용하는 환경에 따라, 작은 동물, 울창한 숲속에 있는 개체, 빠르게 움직이는 동물을 탐지하는 것이 제한된다. 또한, 기상환경에 따라서도 비행이 불가할 수 있고, 배터리 용량으로 인한 비행시간의 제한도 존재한다. 하지만, 정밀한 탐지가 불가능하더라도, 이와 관련 연구가 꾸준히 수행되고 있으며, 선행연구들은 육상 및 해상 포유류, 조류, 그리고 파충류 등을 탐지하는 데에 성공하였다. UAV를 통해 얻어지는 가장 대표적인 데이터는 실화상 이미지이다. 이를 사용해 머신러닝 및 딥러닝 (ML-DL, Machine Learning and Deep Learning) 방법이 주로 사용되고 있다. 이러한 방법은 상대적으로 정확한 탐지 결과를 보여주지만, 특정 종을 탐지할 수 있는 모델의 개발을 위해선 최소한 천 장의 이미지가 필요하다. 실화상 이미지 외에도, 열화상 이미지 또한 UAV를 통해 획득 될 수 있다. 열화상 센서 기술의 개발과 센서 가격의 하락은 많은 야생동물 연구자들의 관심을 사로잡았다. 열화상 카메라를 사용하면 동물의 체온과 주변환경과의 온도 차이를 통해 정온동물을 탐지하는 것이 가능하다. 하지만, 새로운 데이터가 사용되더라도, 여전히 ML-DL 방법이 동물 탐지에 주로 사용되고 있으며, 이러한 방법은 UAV를 활용한 야생동물의 실시간 탐지를 제한한다. 따라서, 본 연구는 열화상과 실화상 이미지를 활용한 동물 자동 탐지 방법의 개발과, 개발된 방법이 이전 방법들의 평균 이상의 정확도와 함께 현장에서 실시간으로 사용될 수 있도록 하는 것을 목표로 한다.For wildlife detection and monitoring, traditional methods such as direct observation and capture-recapture have been carried out for diverse purposes. However, these methods require a large amount of time, considerable expense, and field-skilled experts to obtain reliable results. Furthermore, performing a traditional field survey can result in dangerous situations, such as an encounter with wild animals. Remote monitoring methods, such as those based on camera trapping, GPS collars, and environmental DNA sampling, have been used more frequently, mostly replacing traditional survey methods, as the technologies have developed. But these methods still have limitations, such as the lack of ability to cover an entire region or detect individual targets. To overcome those limitations, the unmanned aerial vehicle (UAV) is becoming a popular tool for conducting a wildlife census. The main benefits of UAVs are able to detect animals remotely covering a wider region with clear and fine spatial and temporal resolutions. In addition, by operating UAVs investigate hard to access or dangerous areas become possible. However, besides these advantages, the limitations of UAVs clearly exist. By UAV operating environments such as study site, flying height or speed, the ability to detect small animals, targets in the dense forest, tracking fast-moving animals can be limited. And by the weather, operating UAV is unable, and the flight time is limited by the battery matters. Although detailed detection is unavailable, related researches are developing and previous studies used UAV to detect terrestrial and marine mammals, avian and reptile species. The most common type of data acquired by UAVs is RGB images. Using these images, machine-learning and deep-learning (ML–DL) methods were mainly used for wildlife detection. ML–DL methods provide relatively accurate results, but at least 1,000 images are required to develop a proper detection model for specific species. Instead of RGB images, thermal images can be acquired by a UAV. The development of thermal sensor technology and sensor price reduction has attracted the interest of wildlife researchers. Using a thermal camera, homeothermic animals can be detected based on the temperature difference between their bodies and the surrounding environment. Although the technology and data are new, the same ML–DL methods were typically used for animal detection. These ML-DL methods limit the use of UAVs for real-time wildlife detection in the field. Therefore, this paper aims to develop an automated animal detection method with thermal and RGB image datasets and to utilize it under in situ conditions in real-time while ensuring the average-above detection ability of previous methods.Abstract I Contents IV List of Tables VII List of Figures VIII Chapter 1. Introduction 1 1.1 Research background 1 1.2 Research goals and objectives 10 1.2.1 Research goals 10 1.2.2 Research objectives 11 1.3 Theoretical background 13 1.3.1 Concept of the UAV 13 1.3.2 Concept of the thermal camera 13 Chapter 2. Methods 15 2.1 Study site 15 2.2 Data acquisition and preprocessing 16 2.2.1 Data acquisition 16 2.2.2 RGB lens distortion correction and clipping 19 2.2.3 Thermal image correction by fur color 21 2.2.4 Unnatural object removal 22 2.3 Animal detection 24 2.3.1 Sobel edge creation and contour generation 24 2.3.2 Object detection and sorting 26 Chapter 3. Results 30 3.1 Number of counted objects 31 3.2 Time costs of image types 33 Chapter 4. Discussion 36 4.1 Reference comparison 36 4.2 Instant detection 40 4.3 Supplemental usage 41 4.4 Utility of thermal sensors 42 4.5 Applications in other fields 43 Chapter 5. Conclusions 47 References 49 Appendix: Glossary 61 초록 62석

Third Earth Resources Technology Satellite Symposium. Volume 3: Discipline summary reports

Presentations at the conference covered the following disciplines: (1) agriculture, forestry, and range resources; (2) land use and mapping; (3) mineral resources, geological structure, and landform surveys; (4) water resources; (5) marine resources; (6) environment surveys; and (7) interpretation techniques