NARF22: Neural Articulated Radiance Fields for Configuration-Aware Rendering

Articulated objects pose a unique challenge for robotic perception and manipulation. Their increased number of degrees-of-freedom makes tasks such as localization computationally difficult, while also making the process of real-world dataset collection unscalable. With the aim of addressing these scalability issues, we propose Neural Articulated Radiance Fields (NARF22), a pipeline which uses a fully-differentiable, configuration-parameterized Neural Radiance Field (NeRF) as a means of providing high quality renderings of articulated objects. NARF22 requires no explicit knowledge of the object structure at inference time. We propose a two-stage parts-based training mechanism which allows the object rendering models to generalize well across the configuration space even if the underlying training data has as few as one configuration represented. We demonstrate the efficacy of NARF22 by training configurable renderers on a real-world articulated tool dataset collected via a Fetch mobile manipulation robot. We show the applicability of the model to gradient-based inference methods through a configuration estimation and 6 degree-of-freedom pose refinement task. The project webpage is available at: https://progress.eecs.umich.edu/projects/narf/.Comment: Accepted to the 2022 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS). Contact: Stanley Lewis, [email protected]

Counter-Hypothetical Particle Filters for Single Object Pose Tracking

Particle filtering is a common technique for six degree of freedom (6D) pose estimation due to its ability to tractably represent belief over object pose. However, the particle filter is prone to particle deprivation due to the high-dimensional nature of 6D pose. When particle deprivation occurs, it can cause mode collapse of the underlying belief distribution during importance sampling. If the region surrounding the true state suffers from mode collapse, recovering its belief is challenging since the area is no longer represented in the probability mass formed by the particles. Previous methods mitigate this problem by randomizing and resetting particles in the belief distribution, but determining the frequency of reinvigoration has relied on hand-tuning abstract heuristics. In this paper, we estimate the necessary reinvigoration rate at each time step by introducing a Counter-Hypothetical likelihood function, which is used alongside the standard likelihood. Inspired by the notions of plausibility and implausibility from Evidential Reasoning, the addition of our Counter-Hypothetical likelihood function assigns a level of doubt to each particle. The competing cumulative values of confidence and doubt across the particle set are used to estimate the level of failure within the filter, in order to determine the portion of particles to be reinvigorated. We demonstrate the effectiveness of our method on the rigid body object 6D pose tracking task.Comment: International Conference on Robotics and Automation (ICRA) 202

Determination of automatic weather station self‐heating originating from accompanying electronics

open7openPavlasek, P.; Merlone, A.; Sanna, F.; Coppa, G.; Izquierdo, C. G.; Palencar, J.; Duris, S.Pavlasek, P.; Merlone, A.; Sanna, F.; Coppa, G.; Izquierdo, C. G.; Palencar, J.; Duris, S

О СЛУЧАЯХ ВСТРЕЧАЕМОСТИ Ascaridia galli (Schrank, 1788) FREEBORN, 1923 В ЯЙЦАХ КУР И ИХ ПРИЧИНА

Analysis of the generalized literature reports and the own case of detection Ascaridia galli in chicken eggs is provided. Data on migration and unusual localization of these nematodes and larvae of species of the suborder Ascaridata are being discussed (Skryabin, 1915). The results allow us to presume that the incorrect localization of parasites is not casuistry but a component of parasites' evolution, their survival and expansion of their habitat. Description of morphology A. galli detected in a bird's egg is submitted. Figures of separate body parts and organs A. galli are presented. The unusual localization of helminths is a result of changing physical and biochemical conditions of their habitat and biological competition with other inhabitants including own species at high intensity of infection. Measures of protection against ascariasis and its therapy are necessary to prevent ascarids (roundworms) in birds' eggs. The prevention measures consist in avoiding infection of birds. The results of coproovoscopy shown that birds’ dehelmintization contributes to their migration. Представлен анализ обобщенных литературных сообщений и собственного случая обнаружения аскаридий Ascaridia galli в яйцах кур. Обсуждаются данные о миграции и необычной локализации этих нематод и личинок представителей подотряда Ascaridata (Sckrjabin, 1915). Результаты дают возможность считать, что «извращенная» локализация не казуистическое явление, а эволюционная составляющая паразитов, их выживаемости и расширения сферы обитания. Дано описание морфологии A. galli, обнаруженных в яйце птицы. Приведены рисунки отдельных частей и органов A. galli. Необычная локализация гельминтов является следствием изменения физических и биохимических условий среды их обитания и биологическая конкуренция с другими обитателями, в том числе и собственного вида при высокой интенсивности инвазии. Предупреждением появления аскаридий в яйцах птиц служит профилактика и терапия аскаридиоза. Профилактика заключается в недопущении заражения птиц. Дегельминтизация по результатам копроовоскопии способствует их миграции.