Rafael Padilha

Rafael Padilha
University of Campinas | UNICAMP · Institute of Computing

Master of Science

About

22
Publications
4,605
Reads
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203
Citations
Citations since 2016
20 Research Items
193 Citations
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Introduction
I am a PhD student from the Institute of Computing, University of Campinas in Brazil and also a member of Reasoning for Complex Data Lab (RECOD). I am currently a visiting scholar under University of Kentucky (USA). My current research involves discovering how a machine can perceive the passage of time in pictures and videos using only visual evidences, such as movement of dynamic elements, differences in illumination and shadows, and also semantic changes in the scene.
Additional affiliations
August 2017 - June 2021
University of Campinas
Position
  • PhD Student
January 2015 - July 2017
University of Campinas
Position
  • Master's Student
August 2012 - July 2013
University of Campinas
Position
  • Student
Description
  • Undergraduate research student working on automatic detection of diabetic retinopathy through learning algorithms and image processing techniques. Development of software capable of analyzing the quality of eye images.
Education
January 2015 - December 2016
University of Campinas
Field of study
  • Computer Science
January 2009 - December 2014
University of Campinas
Field of study
  • Computer Science

Publications

Publications (22)
Conference Paper
Deep learning classifiers can achieve high accuracy in many medical imaging analysis problems. However, when evaluating images from outside the training distribution --- e.g., from new patients or generated by different medical equipment --- their performance is often hindered, highlighting that they might have learned specific characteristics and...
Conference Paper
Full-text available
One of the major modern threats to society is the propagation of misinformation --- fake news, science denialism, hate speech --- fueled by social media's widespread adoption. On the leading social platforms, millions of automated and fake profiles exist only for this purpose. One step to mitigate this problem is verifying the authenticity of profi...
Article
Full-text available
Most pictures shared online are accompanied by temporal metadata (i.e., the day and time they were taken), which makes it possible to associate an image content with real-world events. Maliciously manipulating this metadata can convey a distorted version of reality. In this work, we present the emerging problem of detecting timestamp manipulation....
Article
Full-text available
The face is the window to the soul. This is what the 19th-century French doctor Duchenne de Boulogne thought. Using electric shocks to stimulate muscular contractions and induce bizarre-looking expressions, he wanted to understand how muscles produce facial expressions and reveal the most hidden human emotions. Two centuries later, this research fi...
Conference Paper
Full-text available
Mass testing of the population is among the most effective measures to combat the COVID-19 pandemic. Among existing diagnostic methods, deep learning-based solutions have the potential to be affordable, quick and accurate. However, these techniques often rely on high-quality datasets, which are not always available in medical scenarios. In this wor...
Chapter
Full-text available
Through our devices, we are able to record and share content, fomenting the generation of information about what happens around us. An example is a massive blaze that struck Notre Dame Cathedral, in April 2019, during which millions of images and videos were recorded and simultaneously shared on the Internet by the media at large and everyday citiz...
Article
Full-text available
As smartphones become ubiquitous in modern life, every major event --- from musical concerts to terrorist attempts --- is massively captured by multiple devices and instantly uploaded to the Internet. Once shared through social media, the chronological order between available media pieces cannot be reliably recovered, hindering the understanding an...
Article
Full-text available
A Ciência Forense Digital surgiu da necessidade de tratar problemas forenses na era digital. Seu mais recente desafio está relacionado ao surgimento das mídias sociais, intensificado pelos avanços da Inteligência Artificial. A produção massiva de dados nas mídias sociais tornou a análise forense mais complexa, especialmente pelo aperfeiçoamento de...
Preprint
Full-text available
Most pictures shared online are accompanied by a temporal context (i.e., the moment they were taken) that aids their understanding and the history behind them. Claiming that these images were captured in a different moment can be misleading and help to convey a distorted version of reality. In this work, we present the nascent problem of detecting...
Conference Paper
Full-text available
The COVID-19 pandemic impacted all spheres of our society. The outbreak increased the pressure on public health systems, urging the scientific community to develop and evaluate methods to reliably diagnose patients. Driven by their effectiveness in medical imaging analysis, deep neural networks have been seen as a possible alternative to automatica...
Article
Full-text available
With the widespread use of biometric authentication comes the exploitation of presentation attacks, possibly undermining the effectiveness of these technologies in real-world setups. One example takes place when an impostor, aiming at unlocking someone else’s smartphone, deceives the built-in face recognition system by presenting a printed image of...
Patent
Full-text available
A method includes receiving probe image data associated with a biometric authentication request on a mobile device. A first classifier is employed to generate a first probability metric of the probe image data being associated with the authorized user. The biometric authentication request is approved responsive to the first probability metric being...
Article
Full-text available
We discuss the problem of restructuring visual data from different heterogeneous sources to analyze an event of interest. We present X-coherence: a pipeline aiming at organizing and representing pieces of data, tying them coherently with the real world, and with one another. Finally, we outline research challenges while seeking X-coherence.
Article
Full-text available
Mobile devices had their popularity and affordability greatly increased in recent years. As a consequence of their ubiquity, these devices now carry all sorts of personal data that should be accessed only by their owner. Even though knowledge-based procedures are still the main methods to secure the owner's identity, recently biometric traits have...
Conference Paper
Full-text available
We live in a connected society in which no major event-from music concerts to terrorist attempts-happens without being recorded by a smartphone and shared instantly to the world. This flow of generated data is often unstructured and carries no reliable information with respect to time of capture of such media pieces. Consequently , posterior recons...
Conference Paper
Full-text available
Mobile devices had their popularity and affordability greatly increased in recent years. As a consequence of their ubiquity, these devices now carry all sorts of personal data that should be accessed only by their owner. Even though knowledge-based procedures are still the main methods to secure the owner's identity, recently biometric traits have...
Conference Paper
Full-text available
In recent years, software-based face presentation attack detection (PAD) methods have seen a great progress. However, most existing schemes are not able to generalize well in more realistic conditions. The objective of this competition is to evaluate and compare the generalization performances of mobile face PAD techniques under some real-world var...
Article
Full-text available
Automated identification of diabetic retinopathy has followed a number of paths. For accurate automated lesion detection, the first step is to identify images that are not suitable for automated assessment. This is followed by lesion or disease classification. For appropriate referral of individuals, the accurate recognition of a lesion and the ext...
Conference Paper
Full-text available
Screening of Diabetic Retinopathy (DR) with timely treatment prevents blindness. Several researchers have focused their work on the development of computer-aided lesion-specific detectors. Combining detectors is a complex task as frequently the detectors have different properties and constraints and are not designed under a unified framework. We ex...

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Projects

Projects (2)
Project
In this research project, we focus on synchronizing specific events in space and time (X-coherence), fact-checking, and mining persons, objects and contents of interest from various and heterogeneous sources including - but not limited to - the internet, social media and surveillance imagery. For that, we seek to harness information from various media sources and synchronize the multiple textual and visual information pieces around the position of an event or object as well as order them so as to allow a better understanding about what happened before, during, and shortly after the event. After automatically organizing the data and understanding the order of the facts, we can devise and deploy solutions for mining persons or objects of interest for suspect analysis/tracking, fact checking, or even understanding the nature of the said event. Additionally, by exploring the possible existing links among different pieces of information, we aim at further designing and developing media integrity analytics tools to hint at existing forgeries, sensitive content (e.g., violent content, child pornography), and spreading patterns of multimedia objects online. With demanding and sophisticated crimes and terrorist threats becoming ever more pervasive, allied with the advent and spread of fake news, our objective is to use the developed solutions to help us answering the four most important questions in forensics regarding an event: "who," "in what circumstances," "why," and "how," thus identifying the characteristics and circumstances in which an event has taken place.
Project
Individuals can be recognized by their biological and behavioral characteristics such as face, voice and fingerprint. Biometric recognition systems allow the automation of the recognition process, by means of signal processing and machine learning methods. The BioLive Projectis inserted in this context and it aims at exploring open-set authentication techniques for mobile devices.