Audio phylogenetic analysis using geometric transforms

Whenever a multimedia content is shared on the Internet, a mutation process is being operated by multiple users that download, alter and repost a modified version of the original data leading to the diffusion of multiple near-duplicate copies. This effect is also experienced by audio data (e.g., in audio sharing platforms) and requires the design of accurate phylogenetic analysis strategies that permit uncovering the processing history of each copy and identify the original one. This paper proposes a new phylogenetic reconstruction strategy that converts the analyzed audio tracks into spectrogram images and compare them using alignment strategies borrowed from computer vision. With respect to strategies currently-available in literature, the proposed solution proves to be more accurate, does not require any a-priori knowledge about the operated transformations, and requires a significantly-lower amount of computational time

Stay True to the Sound of History: Philology, Phylogenetics and Information Engineering in Musicology

This work investigates computational musicology for the study of tape music works tackling the problems concerning stemmatics. These philological problems have been analyzed with an innovative approach considering the peculiarities of audio tape recordings. The paper presents a phylogenetic reconstruction strategy that relies on digitizing the analyzed tapes and then converting each audio track into a two-dimensional spectrogram. This conversion allows adopting a set of computer vision tools to align and equalize different tracks in order to infer the most likely transformation that converts one track into another. In the presented approach, the main editing techniques, intentional and unintentional alterations and different configurations of a tape recorded are estimated in phylogeny analysis. The proposed solution presents a satisfying robustness to the adoption of the wrong reading setup together with a good reconstruction accuracy of the phylogenetic tree. The reconstructed dependencies proved to be correct or plausible in 90% of the experimental cases

Cultural Context-Aware Models and IT Applications for the Exploitation of Musical Heritage

Information engineering has always expanded its scope by inspiring innovation in different scientific disciplines. In particular, in the last sixty years, music and engineering have forged a strong connection in the discipline known as “Sound and Music Computing”. Musical heritage is a paradigmatic case that includes several multi-faceted cultural artefacts and traditions. Several issues arise from the analog-digital transfer of cultural objects, concerning their creation, preservation, access, analysis and experiencing. The keystone is the relationship of these digitized cultural objects with their carrier and cultural context. The terms “cultural context” and “cultural context awareness” are delineated, alongside the concepts of contextual information and metadata. Since they maintain the integrity of the object, its meaning and cultural context, their role is critical. This thesis explores three main case studies concerning historical audio recordings and ancient musical instruments, aiming to delineate models to preserve, analyze, access and experience the digital versions of these three prominent examples of musical heritage. The first case study concerns analog magnetic tapes, and, in particular, tape music, a particular experimental music born in the second half of the XX century. This case study has relevant implications from the musicology, philology and archivists’ points of view, since the carrier has a paramount role and the tight connection with its content can easily break during the digitization process or the access phase. With the aim to help musicologists and audio technicians in their work, several tools based on Artificial Intelligence are evaluated in tasks such as the discontinuity detection and equalization recognition. By considering the peculiarities of tape music, the philological problem of stemmatics in digitized audio documents is tackled: an algorithm based on phylogenetic techniques is proposed and assessed, confirming the suitability of these techniques for this task. Then, a methodology for a historically faithful access to digitized tape music recordings is introduced, by considering contextual information and its relationship with the carrier and the replay device. Based on this methodology, an Android app which virtualizes a tape recorder is presented, together with its assessment. Furthermore, two web applications are proposed to faithfully experience digitized 78 rpm discs and magnetic tape recordings, respectively. Finally, a prototype of web application for musicological analysis is presented. This aims to concentrate relevant part of the knowledge acquired in this work into a single interface. The second case study is a corpus of Arab-Andalusian music, suitable for computational research, which opens new opportunities to musicological studies by applying data-driven analysis. The description of the corpus is based on the five criteria formalized in the CompMusic project of the University Pompeu Fabra of Barcelona: purpose, coverage, completeness, quality and re-usability. Four Jupyter notebooks were developed with the aim to provide a useful tool for computational musicologists for analyzing and using data and metadata of such corpus. The third case study concerns an exceptional historical musical instrument: an ancient Pan flute exhibited at the Museum of Archaeological Sciences and Art of the University of Padova. The final objective was the creation of a multimedia installation to valorize this precious artifact and to allow visitors to interact with the archaeological find and to learn its history. The case study provided the opportunity to study a methodology suitable for the valorization of this ancient musical instrument, but also extendible to other artifacts or museum collections. Both the methodology and the resulting multimedia installation are presented, followed by the assessment carried out by a multidisciplinary group of experts

DeePhy: On Deepfake Phylogeny

Deepfake refers to tailored and synthetically generated videos which are now prevalent and spreading on a large scale, threatening the trustworthiness of the information available online. While existing datasets contain different kinds of deepfakes which vary in their generation technique, they do not consider progression of deepfakes in a "phylogenetic" manner. It is possible that an existing deepfake face is swapped with another face. This process of face swapping can be performed multiple times and the resultant deepfake can be evolved to confuse the deepfake detection algorithms. Further, many databases do not provide the employed generative model as target labels. Model attribution helps in enhancing the explainability of the detection results by providing information on the generative model employed. In order to enable the research community to address these questions, this paper proposes DeePhy, a novel Deepfake Phylogeny dataset which consists of 5040 deepfake videos generated using three different generation techniques. There are 840 videos of one-time swapped deepfakes, 2520 videos of two-times swapped deepfakes and 1680 videos of three-times swapped deepfakes. With over 30 GBs in size, the database is prepared in over 1100 hours using 18 GPUs of 1,352 GB cumulative memory. We also present the benchmark on DeePhy dataset using six deepfake detection algorithms. The results highlight the need to evolve the research of model attribution of deepfakes and generalize the process over a variety of deepfake generation techniques. The database is available at: http://iab-rubric.org/deephy-databaseComment: Accepted at 2022, International Joint Conference on Biometrics (IJCB 2022

Minimum spanning tree reconstruction using autoencoders

Minimum spanning trees are widely used graph structures used to find relationships between data organized in a graph. This work proposes a new approach based on neural networks, in particular, autoencoders, to extrapolate this tree from the dissimilarity representation of the data, seen as a noisy version of the minimum spanning tree. After many tests done on different network, the final results confirm the validity of the idea

Visual Computing and Machine Learning Techniques for Digital Forensics

It is impressive how fast science has improved day by day in so many different fields. In special, technology advances are shocking so many people bringing to their reality facts that previously were beyond their imagination. Inspired by methods earlier presented in scientific fiction shows, the computer science community has created a new research area named Digital Forensics, which aims at developing and deploying methods for fighting against digital crimes such as digital image forgery.This work presents some of the main concepts associated with Digital Forensics and, complementarily, presents some recent and powerful techniques relying on Computer Graphics, Image Processing, Computer Vision and Machine Learning concepts for detecting forgeries in photographs. Some topics addressed in this work include: sourceattribution, spoofing detection, pornography detection, multimedia phylogeny, and forgery detection. Finally, this work highlights the challenges and open problems in Digital Image Forensics to provide the readers with the myriad opportunities available for research

Reconstrução de filogenias para imagens e vídeos

Orientadores: Anderson de Rezende Rocha, Zanoni DiasTese (doutorado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: Com o advento das redes sociais, documentos digitais (e.g., imagens e vídeos) se tornaram poderosas ferramentas de comunicação. Dada esta nova realidade, é comum esses documentos serem publicados, compartilhados, modificados e republicados por vários usuários em diferentes canais da Web. Além disso, com a popularização de programas de edição de imagens e vídeos, muitas vezes não somente cópias exatas de documentos estão disponíveis, mas, também, versões modificadas das fontes originais (duplicatas próximas). Entretanto, o compartilhamento de documentos facilita a disseminação de conteúdo abusivo (e.g., pornografia infantil), que não respeitam direitos autorais e, em alguns casos, conteúdo difamatório, afetando negativamente a imagem pública de pessoas ou corporações (e.g., imagens difamatórias de políticos ou celebridades, pessoas em situações constrangedoras, etc.). Muitos pesquisadores têm desenvolvido, com sucesso, abordagens para detecção de duplicatas de documentos com o intuito de identificar cópias semelhantes de um dado documento multimídia (e.g., imagem, vídeo, etc.) publicado na Internet. Entretanto, somente recentemente têm se desenvolvido as primeiras pesquisas para ir além da detecção de duplicatas e encontrar a estrutura de evolução de um conjunto de documentos relacionados e modificados ao longo do tempo. Para isso, é necessário o desenvolvimento de abordagens que calculem a dissimilaridade entre duplicatas e as separem corretamente em estruturas que representem a relação entre elas de forma automática. Este problema é denominado na literatura como Reconstrução de Filogenia de Documentos Multimídia. Pesquisas na área de filogenia de documentos multimídia são importantes para auxiliar na resolução de problemas como, por exemplo, análise forense, recuperação de imagens por conteúdo e rastreamento de conteúdo ilegal. Nesta tese de doutorado, apresentamos abordagens desenvolvidas para solucionar o problema de filogenias para imagens e vídeos digitais. Considerando imagens, propomos novas abordagens para tratar o problema de filogenia considerando dois pontos principais: (i) a reconstrução de florestas, importante em cenários onde se tem um conjunto de imagens semanticamente semelhantes, mas geradas por fontes ou em momentos diferentes no tempo; e (ii) novas medidas para o cálculo de dissimilaridade entre as duplicatas, uma vez que esse cálculo afeta diretamente a qualidade de reconstrução da filogenia. Os resultados obtidos com as soluções para filogenia de imagens apresentadas neste trabalho confirmam a efetividade das abordagens propostas, identificando corretamente as raízes das florestas (imagens originais de uma sequencia de evolução) com até 95% de acurácia. Para filogenia de vídeos, propomos novas abordagens que realizam alinhamento temporal nos vídeos antes de se calcular a dissimilaridade, uma vez que, em cenários reais, os vídeos podem estar desalinhados temporalmente, terem sofrido recorte temporal ou serem comprimidos, por exemplo. Nesse contexto, nossas abordagens conseguem identificar a raiz das árvores com acurácia de até 87%Abstract: Digital documents (e.g., images and videos) have become powerful tools of communication with the advent of social networks. Within this new reality, it is very common these documents to be published, shared, modified and often republished by multiple users on different web channels. Additionally, with the popularization of image editing software and online editor tools, in most of the cases, not only their exact duplicates will be available, but also manipulated versions of the original source (near duplicates). Nevertheless, this document sharing facilitates the spread of abusive content (e.g., child pornography), copyright infringement and, in some cases, defamatory content, adversely affecting the public image of people or corporations (e.g., defamatory images of politicians and celebrities, people in embarrassing situations, etc.). Several researchers have successfully developed approaches for the detection and recognition of near-duplicate documents, aiming at identifying similar copies of a given multimedia document (e.g., image, video, etc.) published on the Internet. Notwithstanding, only recently some researches have developed approaches that go beyond the near-duplicate detection task and aim at finding the ancestral relationship between the near duplicates and the original source of a document. For this, the development of approaches for calculating the dissimilarity between near duplicates and correctly reconstruct structures that represent the relationship between them automatically is required. This problem is referred to in the literature as Multimedia Phylogeny. Solutions for multimedia phylogeny can help researchers to solve problems in forensics, content-based document retrieval and illegal-content document tracking, for instance. In this thesis, we designed and developed approaches to solve the phylogeny reconstruction problem for digital images and videos. Considering images, we proposed approaches to deal with the phylogeny problem considering two main points: (i) the forest reconstruction, an important task when we consider scenarios in which there is a set of semantically similar images, but generated by different sources or at different times; and (ii) new measures for dissimilarity calculation between near-duplicates, given that the dissimilarity calculation directly impacts the quality of the phylogeny reconstruction. The results obtained with our approaches for image phylogeny showed effective, identifying the root of the forests (original images of an evolution sequence) with accuracy up to 95%. For video phylogeny, we developed a new approach for temporal alignment in the video sequences before calculating the dissimilarity between them, once that, in real-world conditions, a pair of videos can be temporally misaligned, one video can have some frames removed and video compression can be applied, for example. For such problem, the proposed methods yield up to 87% correct of accuracy for finding the roots of the treesDoutoradoCiência da ComputaçãoDoutor em Ciência da Computação2013/05815-2FAPESPCAPE