Leveraging deep neural networks to fight child pornography in the age of social media

Over the past two decades, the nature of child pornography in terms of generation, distribution and possession of images drastically changed, evolving from basically covert and offline exchanges of content to a massive network of contacts and data sharing. Nowadays, the internet has become not only a transmission channel but, probably, a child pornography enabling factor by itself.

The use of deep convolution neural networks for sexually exploitative imagery of children (SEIC) is challenging, since those models require large amounts of training data. To bypass that problem, in this paper, the authors proposed a data-driven solution in which: (1) transfer the network parameters and configurations trained on ImageNet to the target problem detection (1-tiered solution) and (2) perform a 2-tiered transfer learning procedure, in which knowledge is transferred from the a network trained over ImageNet to the problem of adult content detection and fine-tune the network for detecting child pornography content in an image problem.

The proposed method outperform different existing solutions and seem to represent an important step forward when dealing with child pornography content detection. The solutions are encapsulated in a sandbox virtual machine ready for deployment by experts and practitioners.

Classification error reduction (%) with respect to our 2-tiered SEIC Detector considering the metric ACC reported in the article.

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DéjàVu Post-doctoral Fellowship

The Thematic Research Project, entitled DéjàVu: Feature-Space-Time Coherence from Heterogeneous Data form Media Integrity and Interpretation of Events funded by FAPESP is seeking candidates for a 2-year (renewable) post-doctoral fellowship position to work at the Reasoning for Complex Data (RECOD) Lab.

The project relies upon collaborators from all over the globe such as the University of Campinas (Brazil), University of São Paulo in São Carlos (Brazil), Federal University of Minas Gerais (Brazil), Purdue University (USA), University of Notre Dame (USA), Politécnico di Milano (Italy), University of Siena (Italy), Nanyang Technological University, NTU (Singapore) and others.

More Information about the Project

In this 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. 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.

The Position

This fellowship position requires research and development in Computer Vision, Machine Learning and Visual Analytics, in collaboration with graduate students and partners. The work of the fellow will be focused on machine learning and visual analytics methods to perform X-coherence, or in other words, to find out the order of facts related to an event in space and time.

It is desirable that the candidate demonstrates domain knowledge in machine learning, visual analytics, and computer vision. However, candidates with good mathematical and programming backgrounds in any of the three areas and motivation to learn the others are equally welcomed.

The post-doctoral fellowship includes a monthly stipend of R$ 7,174.80 (about USD 2,300 and EU$ 2,000), access to the health-care system of Unicamp, and research contingency funds (15% of the annual value of the fellowship, each year). For more details, check out Fapesp’s webpage.

How to Apply

Interested candidates should email Prof. Anderson Rocha, project’s coordinator, before February 20th, 2018 with:

  • A motivation letter for the application;
  • A recommendation letter from a previous supervisor;
  • Curriculum vitae with the list of publications, education background, research track-record and experience, and copy of diplomas/degree certificate(s).

Additional Information

Eligibility Criteria Ph.D. in Computer Science or related areas (in case you have any doubt about a possible related area, drop an e-mail to the Project’s Coordinator above)

Selection process It will be based on the motivation letter for the application, recommendation letter from a previous supervisor, curriculum vitae with the list of publications, education and experience, and copy of diplomas/degree certificate(s). An interview with the finalists shall take place via Telecom.

Information About Campinas

More details

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RECOD celebrates its 8th year!

This year, our lab celebrated its eighth year of success together with an end of the year party. We have achieved significant growth in the international scientific community. Also, this year two professors joined RECOD: Adin Rivera and Sandra Avila.

As part of the celebration, we launched a contest for Recod’s 8th Anniversary Logo and the winning one was Yusseli Mendez with this nice orange logo:

Congratulations to all the Researchers, students, alumni, and friends that were part of this journey during this year!

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Talks: LIRMM and WIFS 2017, France

Prof. Anderson Rocha is visiting the Montpellier Laboratory of Informatics, Robotics and Microelectronics (LIRMM), Montpellier, France, hosted by Prof. William Puech. Two talks were/will be given:

Talk #1: Dec. 12th, 2017

Interpretation of Events from Heterogenous Data: How to Connect Existing Pieces of Evidence in Time and Space

Abstract: In this talk, we will discuss problems associated with 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.

Talk #2: Dec. 19th, 2017

Media Integrity Analytics: Beyond Digital Forensics of Single Objects

Abstract: Currently, multimedia objects can be easily created, stored, (re)-transmitted, and edited for good or bad. In this sense, there has been an increasing interest in finding the structure of temporal evolution within a set of documents and how documents are related to one another overtime. This process, also known in the literature as Multimedia Phylogeny, aims at finding the phylogeny tree(s) that best explains the creation process of a set of related documents (e.g., images/videos) and their ancestry relationships. Solutions to this problem have direct applications in forensics, security, copyright enforcement, news tracking services and other areas. In this talk, we explore solutions for reconstructing the evolutionary tree(s) associated with a set of visual documents, more specifically images and videos. This can be useful for aiding experts to track the source of child pornography image broadcasting or the chain of image and video distribution in time, being extremely useful for complex different media provenance tasks. Finally, we will also discuss how to implement such solutions in large-scale considering millions of documents at the same time.


In Rennes, on Dec. 6th, Prof. Anderson gave a talk at IEEE Intl. Workshop on Information Forensics and Security (WIFS 2017) in which he presented the paper:

Authorship Attribution for Social Media Forensics, A. Rocha, W. J. Scheirer, C. W. Forstall, T. Cavalcante, A. Theophilo, B. Shen, A. R. B. Carvalho, and E. Stamatatos, in IEEE Transactions on Information Forensics and Security, vol. 12, no. 1, pp. 5-33, Jan. 2017.

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RECODist has been awared with INOVA Prize 2017

We are very proud to announce that Gabriel Bertocco, one of our RECODists, has been awarded with the Unicamp INOVA Prize on Introduction to Innovation 2017. Supervised by Prof. Anderson Rocha and Fernanda Andaló, the work entitled “Automatic age range estimation on mobile devices” is the result of a partnership between RECOD and Motorola. The Unicamp INOVA Prize awarded to most innovative works in applied or basic sciences made by undergraduate students under scientific tutorial at Unicamp.

Another research work from RECOD, entitled “CrowdPet: Deep learning applied to the detection of dogs in the wild”, was also among the finalists in the technological area.

The related links are (in Portuguese):

http://www.inova.unicamp.br/noticia/premio-inova-premia-3-pesquisas-com-grande-potencial-de-beneficiar-a-sociedade/

http://www.inova.unicamp.br/noticia/conheca-os-projetos-vencedores-do-premio-inova-de-iniciacao-a-inovacao/

http://www.inova.unicamp.br/noticia/finalistas-do-premio-inova-de-iniciacao-a-inovacao-tem-projetos-avaliados-no-congresso-de-ic/

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Talk: Alex Kot from NTU, Singapore

The first DéjàVu invited talked happened this week, on Nov. 27th, at IC/Unicamp. In his talk, Prof. Alex Kot, director of ROSE Lab at Nanyang Technological University (NTU), Singapore, presented the most relevant ongoing research project at the Rapid-Rich Object Search (ROSE) Lab, which is comprised of 12 faculty, 26 research staff and a total of 48 PhD students from the Schools of Electrical & Electronic Engineering (EEE) and Computer Science & Engineering (SCSE) at the NTU.

The ROSE Lab is focusing on visual object search (including object classification, recognition, & retrieval); deep learning & visual analytics (including anomaly detection, pedestrian detection, person re-identification, object tracking, action recognition); as well as multimedia forensics & biometrics (including face spoofing & liveness detection) Since 2012, the ROSE Lab has secured 24 industry partners, including Tencent (one of the largest Internet companies in Asia), NVIDIA (the world’s leading visual computing company), Accenture (one of the world’s leading management consulting companies), and OMRON (a leading Japanese industry automation company).

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1st Workshop of “The Secret of Playing Football: Brazil versus the Netherlands” project

On last Nov. 9th, 2017 the first workshop of the FAPESP research project entitled “The Secret of Playing Football: Brazil versus the Netherlands” took place at FEF/Unicamp. The presentations were given by Prof. Miguel de Arruda (FEF director), Prof. Ricardo Torres (project PI), Prof. Claudio Gobatto, Prof. Thomas Beltrame, Prof. Barreto, Prof. Felipe Moura, Prof. Paulo Santiago, Prof. Paulo Ruffino and Prof. Sergio Cunha.

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1st Advanced Computing Workshop

The 1st Advanced Computing Workshop, which is in partnership with the Army Research Office/US, took place in São Paulo on November 13th, 2017. In the video below, Prof. Anderson Rocha explains how three RECOD’s projetcs, DeepEyes, MediFor and DéjàVu, are related and how they are contributing with Digital Forensics research advances.

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RECODists Talks

During the last weeks, RECODists were performing several talks about the research projects we have been carrying on. They are:

  • Deep Learning” at EncPos 2017, IMECC Unicamp – Eduardo Valle

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DéjàVu on the news

Fapesp DéjàVu project, which will start soon, is attracting attention of Brazilian press for its high objectives and potential of impact in the society at large. They are (in Portuguese):

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