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Andrew Philippides

Publications and source records attributed to Andrew Philippides.

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A 3D-Printable Dataset for Fair Testing and Comparisons of Tactile Sensors

Existing texture datasets for tactile sensing primarily consist of sensor readings from a specific sensor interacting with available surfaces/objects rather than describing the textures themselves, limiting fair comparison between tactile sensors and hindering reproducible research. In this work, we introduce a 3D-printable dataset of mathematically defined textures designed to be fabricated reliably across different printers and filament types. The dataset consists of six parametrically generated surface patterns derived from combinations of sine-wave and Fourier-based functions, giving controlled variation in spatial frequency, amplitude, and directional structure. We evaluate the reproducibility of these textures across three popular 3D printers and multiple filament types by measuring variance in images captured using an optical TacTip sensor under controlled contact conditions. Our results show that print quality, particularly peak sharpness and stringing, affects tactile variance, with higher-end printers producing significantly more consistent signatures. Classification experiments using neural networks and PCA-based models further demonstrate that high-quality prints support strong within-printer generalisation, while cross-printer generalisation remains challenging due to geometric inconsistencies. This work establishes the first openly available, physically reproducible 3D-printed texture benchmark, providing a foundation for fair comparison of tactile sensors.

cs.RO

VidereX: A Navigational Application inspired by ants

Navigation is a crucial element in any person's life, whether for work, education, social living or any other miscellaneous reason; naturally, the importance of it is universally recognised and valued. One of the critical components of navigation is vision, which facilitates movement from one place to another. Navigating unfamiliar settings, especially for the blind or visually impaired, can pose significant challenges, impacting their independence and quality of life. Current assistive travel solutions have shortcomings, including GPS limitations and a demand for an efficient, user-friendly, and portable model. Addressing these concerns, this paper presents VidereX: a smartphone-based solution using an ant-inspired navigation algorithm. Emulating ants' ability to learn a route between nest and feeding grounds after a single traversal, VidereX enables users to rapidly acquire navigational data using a one/few-shot learning strategy. A key component of VidereX is its emphasis on active user engagement. Like ants with a scanning behaviour to actively investigate their environment, users wield the camera, actively exploring the visual landscape. Far from the passive reception of data, this process constitutes a dynamic exploration, echoing nature's navigational mechanisms.

cs.HC

EchoVPR: Echo State Networks for Visual Place Recognition

Recognising previously visited locations is an important, but unsolved, task in autonomous navigation. Current visual place recognition (VPR) benchmarks typically challenge models to recover the position of a query image (or images) from sequential datasets that include both spatial and temporal components. Recently, Echo State Network (ESN) varieties have proven particularly powerful at solving machine learning tasks that require spatio-temporal modelling. These networks are simple, yet powerful neural architectures that--exhibiting memory over multiple time-scales and non-linear high-dimensional representations--can discover temporal relations in the data while still maintaining linearity in the learning time. In this paper, we present a series of ESNs and analyse their applicability to the VPR problem. We report that the addition of ESNs to pre-processed convolutional neural networks led to a dramatic boost in performance in comparison to non-recurrent networks in five out of six standard benchmarks (GardensPoint, SPEDTest, ESSEX3IN1, Oxford RobotCar, and Nordland), demonstrating that ESNs are able to capture the temporal structure inherent in VPR problems. Moreover, we show that models that include ESNs can outperform class-leading VPR models which also exploit the sequential dynamics of the data. Finally, our results demonstrate that ESNs improve generalisation abilities, robustness, and accuracy further supporting their suitability to VPR applications.

cs.CV