arXiv subjects

Paulo Peixoto

Publications and source records attributed to Paulo Peixoto.

3 recordsLinked to original sources

arXiv2026

Autonomous Telerehabilitation via Skeletal Motion Prediction and Joint-Level Performance Assessment

Autonomous rehabilitation systems must not only recognize human motion but also provide structured feedback to support users without continuous therapist supervision. This paper presents a telerehabilitation pipeline that integrates skeleton-based exercise quality assessment and short-term motion prediction into a two-module system operating on marker-free RGB video. A self-attentive Bidirectional LSTM performs exercise quality classification using MMD-NCA metric learning, while a graph-based motion prediction module computes per-joint position errors between predicted and observed poses, generating spatially localized deviation signals. Each module is evaluated independently on established benchmarks: the classifier achieves 96.45% mean-class accuracy on squat sequences from the PROZIS dataset, and the adopted STARS predictor achieves a mean MPJPE of 75.8 mm at 560 ms on Human3.6M, outperforming graph and recurrent baselines across all prediction horizons. The framework is designed for eventual deployment in assistive robotics and home-based rehabilitation contexts; end-to-end integration and clinical validation are important directions for future work. By combining motion recognition and prediction in a single system, this work contributes a step toward autonomous, feedback-driven telerehabilitation, for more accessible and scalable rehabilitation solutions.

cs.CV↗

arXiv2026

A Numerically-Robust ROS 2 Port of iG-LIO: Diagnosing and Fixing Toolchain-Induced Failures in Incremental GICP LiDAR-Inertial Odometry

iG-LIO is a tightly-coupled LiDAR-inertial odometry system fusing generalized-ICP and point-to-plane constraints in an iterated error-state Kalman filter over an incremental voxel map. We report an open-source ROS 2 Jazzy port of the original ROS 1 implementation and, more importantly, the diagnosis of environment-induced numerical failures that appear only after the port: a mechanically faithful migration -- estimation mathematics left unchanged -- compiled and ran, yet diverged with NaN internal values. Both causes trace to the modern ROS 2 toolchain, not the algorithm: a Quality-of-Service (QoS) mismatch that silently drops and reorders IMU samples, and an uninitialized parallel-reduce accumulator arising from the oneTBB + Eigen combination shipped with current distributions. We further correct Ouster point-field parsing to ensure correct point cloud undistortion with newer Ouster revisions, add Velodyne Velarray M1600 support, provide both a compile-time-gated Livox CustomMsg path and a driver-free path for Livox sensors publishing standard PointCloud2 (e.g. Mid-360), and expose the runtime via YAML. The result has been validated in an Ouster OS0 Rev7, an Ouster OS1 Rev 7, and a Livox MID-360. This report is a citable reference for the port itself, not a claim on the underlying algorithm [1]. The ROS 2 port of iG-LIO described in this document can be found at https://github.com/Forestry-Robotics-UC/ig_lio/tree/ros2-jazzy.

cs.RO↗

arXiv2025

Miniaturized liquid metal composite circuits with energy harvesting coils for battery-free bioelectronics and optogenetics

Over the past years, rapid progress has been made on soft-matter electronics for wearable and implantable devices, for bioelectronics and optogenetics. Liquid Metal (LM) based electronics were especially popular, due to their long-term durability, when subject to repetitive strain cycles. However, one major limitation has been the need for tethering bioelectronics circuits to external power, or the use of rigid bulky batteries. This has motivated a growing interest in wireless energy transfer, which demands circuit miniaturization. However, miniaturization of LM circuits is challenging due to low LM-substrate adhesion, LM smearing, and challenges on microchip-interfacing. In this article, we address these challenges by high-resolution laser-assisted micropatterning of biphasic LM composites and vapor-assisted LM microchip soldering. Through development of a search algorithm for optimization of the biphasic ink coil performance, we designed and implemented micro coils with trace spacing of 50 μm that can harvest a significant amount of energy (178 mW/cm2) through near field inductive coupling. We show miniaturized soft-matter circuits with integrated SMD chips such as NFC chips, capacitors, and LEDs that are implemented in a few minutes through laser patterning, and vaporassisted soldering. In the context of optogenetics, where lightweight, miniaturized systems are needed to provide optical stimulation, soft coils stand out in terms of their improved conformability and flexibility. Thus, this article explores the applications of soft coils in wearable and implantable devices, with a specific focus on their use in optogenetics.

physics.med-ph↗