Citrus orchards under formation evaluated by UAV-Based RGB Imagery

Few studies have investigated the biometric attributes of citrus orchards under formation that use RGB sensors on board unmanned aerial vehicles (UAV) and the challenges are great. This study aimed to develop and validate a method of using aerial UAV images by automated routines to evaluate the biometric attributes of a crop of 'Tahiti' acid lime under formation. We used a multirotor UAV, programmed to capture images at three different map scales, with a frontal and side overlap of 80 %. Geoprocessing was carried out both with and without ground control points on each scale. An automated routine was developed in an open-source environment, consisting of three processing phases: i) Estimation of the plant biometric attributes, ii) Statistical analysis, and iii) Statistical Report Map (SRM). The use of the developed routine allowed to delimit and estimate the crown projection area with an accuracy of more than 95 % as well as identify and quantify the plants with an accuracy of over 97 %. The use of ground control points during the processing stage does not increase accuracy in estimating the biometric attributes under evaluation. On the other hand, map scale is strongly correlated with the quality of the estimates, especially plant height. The results allowed to define a method for the acquisition and analysis of aerophotogrammetric data using a UAV, which can be used to measure the plant biometric attributes under analysis and the method can be easily adapted to perennial crops.

Analysis and characterization of the normal gait phases of walking Warmblood horses as a tool for the diagnosis of lameness / Análise e caracterização das fases do andamento normal dos cavalos através da combinação de fotogrametria e acelerometria como ferramenta para o diagnóstico da claudicação

Horses with lameness modify gait behavior, but when it is subtle, it may not be possible to identify it clinically. The objective of this research is to characterize the normal gait phases of walking Warmblood horses by combining photogrammetry and accelerometry to monitor lameness to indicate a structural or functional disorder in the extremities. The study was conducted in 23 adult male Warmblood horses. Photogrammetry was used to identify the kinematic variables of the limbs and the markers path over time; triaxial accelerometers were used to capture the orthogonal acceleration components. It was determined that only 10 horses showed a normal gait pattern, there was a 43% correspondence between the expert´s judgment and the diagnostic techniques. According to the Stashak classification of the gait phases, cycle phases to forelimb were 34/4/8/13/41, while for hind limb were 54/11/8/8/19 (% of the stride). The range of motion (ROM) of the neck, knee and fetlock joints was 45.52±5.63°, 196.04±19.7° and 209±11.52° respectively. A combination of experimental methods was used to identify the phases of gait cycle of healthy horses. There was a correspondence in the location of the points of maximum displacement of the limbs with both techniques. More detailed information on the limbs movement was obtained using the accelerometer technology. These methods are applicable to other conditions either outdoors or in the lab.(AU)

Os cavalos com claudicação modificam o comportamento do andamento. Porém, uma leve modificação pode não ser identificada clinicamente. O objetivo desta pesquisa foi caracterizar as fases do andamento normal dos cavalos através da combinação de fotogrametria e acelerometria, para identificar alterações estruturais ou funcionais nos membros. O estudo foi conduzido em 23 cavalos Warmblood machos adultos. A partir da fotogrametria foi possível obter as variáveis cinemáticas das extremidades e a trajetória dos marcadores ao longo do tempo. Por outro lado, os acelerômetros triaxiais foram usados para capturar as componentes ortogonais da aceleração. Determinou-se que apenas 10 cavalos mostraram um padrão de marcha normal, e houve uma correspondência de 43% entre pareceres dos peritos e as técnicas de diagnóstico. De acordo com a classificação das fases da marcha de Stashak, as fases do ciclo da extremidade anterior foram 34/4/8/13/41 enquanto para a extremidade posterior foram 54/11/8/8/19. A amplitude de movimento (ROM) de pescoço, joelho e sesamóide foram 45,52±5,63°, 196,04±19,7° e 209±11,52°, respectivamente. Uma combinação dos métodos experimentais foi utilizada para identificar as fases do ciclo de marcha de cavalos saudáveis. Constatou-se correspondência na localização dos pontos de deslocamento máximo do membro com ambas as técnicas. A informação mais detalhada do movimento dos membros foi obtida usando a acelerometria. Estes métodos são aplicáveis em outras condições, quer a campo ou no laboratório.(AU)