Publications de Mario Andres Chavarria Varon

Embedded solution to detect and classify head level objects using stereo vision for visually impaired people with audio feedback

Klaus Benedikt Schönenberger, Mario Andres Chavarria Varon

This work presents an embedded solution for detecting and classifying head-level objects using stereo vision to assist blind individuals. A custom dataset was created, featuring five classes of head-level objects, selected based on a survey of visually imp ...

Springer Science and Business Media LLC2025

Correction: Embedded solution to detect and classify head level objects using stereo vision for visually impaired people with audio feedback

Klaus Benedikt Schönenberger, Mario Andres Chavarria Varon, Silvan Suter

Springer Science and Business Media LLC2025

Challenges and Opportunities of the Human-Centered Design Approach: Case Study Development of an Assistive Device for the Navigation of Persons With Visual Impairment

Klaus Benedikt Schönenberger, Mario Andres Chavarria Varon, Silvan Suter

Background Visual impairment (VI) significantly impacts quality of life, particularly in autonomous pedestrian navigation. Limitations in independent navigation lead to frustration, diminished confidence, and risks to bodily integrity for individuals with ...

JMIR Publications Inc.2025

Barriers for adoption and innovation on rehabilitation technology in low- and middle-income countries: A case study in Colombia

Mario Andres Chavarria Varon

This chapter investigates barriers and opportunities regarding the adoption of innovative technology in the rehabilitation field in low- and middle-income countries (LMICs). We use Colombia as a case study. Colombia has a significant variation in infrastru ...

Taylor and Francis2024

Assessing the implementation of user-centred design standards on assistive technology for persons with visual impairments: a systematic review

Klaus Benedikt Schönenberger, Mario Andres Chavarria Varon

Despite scientific and technological advances in the field of assistive technology (AT) for people with visual impairment (VI), technological designs are frequently based on a poor understanding of the physical and social context of use, resulting in devic ...

Frontiers Media Sa2023

X-ray imaging detector for radiological applications adapted to the context and requirements of low- and middle-income countries

Klaus Benedikt Schönenberger, Hubert Blanchard, René Salathé, Jean-Philippe Thiran, Romain Sahli, Sébastien Emmanuel Blanc, Mario Andres Chavarria Varon, Matthias Hüser, Jérôme Schmid

This paper describes the development of a novel medical x-ray imaging system adapted to the needs and constraints of low- and middle-income countries. The developed system is based on an indirect conversion chain: a scintillator plate produces visible ligh ...

2022

Design Approaches for Creating Person-Centered, Context Sensitive, and Sustainable Assistive Technology with the Global South

Klaus Benedikt Schönenberger, Mario Andres Chavarria Varon

The implementation of non-user-centered design is sometimes effective for traditionally mass-produced items; however, these methods do not take into account local needs, resources, and cultures, and the history of individual people and communities in low- ...

Oxford University Press2021

X-ray imaging detector for radiological applications in the harsh environments of low-income countries

Klaus Benedikt Schönenberger, René Salathé, Jean-Philippe Thiran, Mario Andres Chavarria Varon

This paper describes the development of a novel medical X-ray imaging system adapted to the needs and constraints of low and middle-income countries. The developed system is based on an indirect conversion chain: a scintillator plate produces visible light ...

2020

High sensitivity field asymmetric ion mobility spectrometer

Philippe Marmillod, Giovanni Boero, Jürgen Brugger, Mario Andres Chavarria Varon, Alessandro Valentino Matheoud

A high sensitivity field asymmetric ion mobility spectrometer (FAIMS) was designed, fabricated, and tested. The main components of the system are a 10.6 eV UV photoionization source, an ion filter driven by a high voltage/high frequency n-MOS inverter circ ...

American Institute of Physics2017

Electrical Investigation of Porous Silicon/p-Si Heterojunction Prepared by Electrochemical Etching

Mario Andres Chavarria Varon

We presented the conduction mechanism investigation of porous silicon/p-Si heterojunction fabricated on low resistivity crystalline silicon by electrochemical anodization. Measurements of the current - voltage I(V) and capacitance - voltage C(V) characteri ...

Electrochemical Soc Inc2016

High sensitivity field asymmetric ion mobility spectrometer

Mario Andres Chavarria Varon

Field Asymmetric IonMobility Spectrometry (FAIMS) is a very promising technique for chemical detection. FAIMS systems are portable, highly sensitive, relatively inexpensive and can work at atmospheric conditions. These attributes make it a very desirable t ...

EPFL2016

Effects of the Discharge Parameters on the Efficiency and Stability of Ambient Metastable-Induced Desorption Ionization

Mario Andres Chavarria Varon, Xiao Sheng Zhang

Ionization efficiency is an important factor for ion sources in mass spectrometry and ion mobility spectrometry. Using helium as the discharge gas, acetone as the sample, and high-field asymmetric ion mobility spectrometry (FAIMS) as the ion detection meth ...

Iop Publishing Ltd2015