Joel Baptista

Mr. Joel Baptista

orcid

Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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22 March 2023 in Sensors
Verified
Journal Article
Open access
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JBJoel Baptista
Joel Baptista
Vitor SantosVitor Santos
Vitor Santos
FSFilipe Silva
Filipe Silva
DPDiogo Pinho
Diogo Pinho
Hand gesture recognition from images is a critical task with various real-world applications, particularly in the field of human–robot interaction. Industrial environments, where non-verbal communication is preferred, are significant areas of application for gesture recognition. However, these environments are often unstructured and noisy, with complex and dynamic backgrounds, making accurate hand segmentation a challenging task. Currently, most solutions employ heavy preprocessing to segment the hand, followed by the application of deep learning models to classify the gestures. To address this challenge and develop a more robust and generalizable classification model, we propose a new form of domain adaptation using multi-loss training and contrastive learning. Our approach is particularly relevant in industrial collaborative scenarios, where hand segmentation is difficult and context-dependent. In this paper, we present an innovative solution that further challenges the existing approach by testing the model on an entirely unrelated dataset with different users. We use a dataset for training and validation and demonstrate that contrastive learning techniques in simultaneous multi-loss functions provide superior performance in hand gesture recognition compared to conventional approaches in similar conditions.

14 April 2023 in Journal of Manufacturing Systems
Verified
Journal Article
Open access
Afonso CastroAfonso Castro
Afonso Castro
JBJoel Baptista
Joel Baptista
FSFilipe Silva
Filipe Silva
Vitor SantosVitor Santos
Vitor Santos

17 July 2024 in Robotics
Verified
Journal Article
Open access
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JBJoel Baptista
Joel Baptista
Afonso CastroAfonso Castro
Afonso Castro
Manuel GomesManuel Gomes
Manuel Gomes
PAPedro Amaral
Pedro Amaral
Vitor SantosVitor Santos
Vitor Santos
MOMiguel Oliveira
Miguel Oliveira
This paper presents a collaborative manufacturing cell implemented in a laboratory setting, focusing on developing learning-based interaction abilities to enhance versatility and ease of use. The key components of the system include 3D real-time volumetric monitoring for safety, visual recognition of hand gestures for human-to-robot communication, classification of physical-contact-based interaction primitives during handover operations, and detection of hand–object interactions to anticipate human intentions. Due to the nature and complexity of perception, deep-learning-based techniques were used to enhance robustness and adaptability. The main components are integrated in a system containing multiple functionalities, coordinated through a dedicated state machine. This ensures appropriate actions and reactions based on events, enabling the execution of specific modules to complete a given multi-step task. An ROS-based architecture supports the software infrastructure among sensor interfacing, data processing, and robot and gripper controllers nodes. The result is demonstrated by a functional use case that involves multiple tasks and behaviors, paving the way for the deployment of more advanced collaborative cells in manufacturing contexts.

22 May 2026 in IEEE Access
Verified
Journal Article
Open access
JBJoel Baptista
Joel Baptista
FSFilipe Silva
Filipe Silva
Vitor SantosVitor Santos
Vitor Santos
Anthropomorphic robotic hands offer the potential for human-level dexterity, but their high-dimensional and redundant action spaces pose significant challenges for learning control policies. While recent grasping approaches often reduce the task to static pose prediction followed by motion planning, such methods overlook the dynamic nature of grasping, comprising approach, closure, and lifting phases, each governed by complex contact and inertial dynamics. In contrast, we propose a reinforcement learning framework that learns the entire grasping process by leveraging a synergistic action sub-space. Our method jointly optimizes a control policy and a task-driven action representation via an inverse world model, which learns a low-dimensional latent action space informed by observed state transitions. We evaluate our framework on a subset of YCB objects and show it outperforms baseline methods in success rate and robustness, while also achieving improved zero-shot generalization to unseen objects.