“Imagination is more important than knowledge. For knowledge is limited, whereas imagination embraces the entire world, stimulating progress, giving birth to evolution”

Albert Einstein

Diogo Cabral

(Currently: Postdoctoral Reseacher at HIIT/University of Helsinki. Please, visit my new personal web page!)

I was a  Computer Science Ph.D. student in the School of Sciences and Technology (FCT)NOVA University (UNL), Portugal, advised by Nuno Correia at the Interactive Multimedia GroupCITI. I also have a Ph.D. grant from the UTAustin|Portugal, Digital Media Program.

My research combines multimedia and human-computer interaction topics. In order to improve human-media interaction, my Ph.D. work proposes the use of pen-based technology for video interaction.

Please, see my Publications, Ph.D. Blog, Google Scholar Page and Resume/CV(pdf) for additional info.

E-Mail: diogocabral[at]campus.fct.unl.pt

Research Interests

Main Areas: Multimedia, Human-Computer Interaction.

Specific Interests: Video Visualization, Interaction and Manipulation; Pen-based Technology and Interaction; Bimanual Interaction (pen+touch); Multimedia Interfaces for Electronic Paper.

Present Research

- VideoInk

Due the growth of video sharing, its manipulation is important, however still a hard task. In order to improve it, this work proposes a pen-based approach, called VideoInk. The concept exploits the painting metaphor, replacing digital ink with video frames. The method allows the user to paint video content in a canvas, which works as a two dimensional timeline. This approach includes transition effects and zoom features based on pen pressure. I’m implementing a proof-of-concept prototype in C+ (openCV, openFrameworks and bbTablet) and running on Tablet PCs.

Download the my bbTablet MSVC2010 updateoriginally developed by William Baxter and also updated by Adel Amro.

TKB/Creation-Tool (collaboration with CLUNL/FCSH/UNL, led by Carla Fernandes)

The CREATION-TOOL is an original video annotator that was designed and developed from scratch as a software output deriving from the TKB project. It supports multimodal annotation and is applied to contemporary dance as a creation tool. It was conceived and designed to assist the creative processes of choreographers, functioning as a digital notebook for personal annotations. The prototype, developed for Tablet PCs, allows video annotation in real-time, using a live video stream, or post-event, using a pre-recorded video stream. The tool also allows different video annotation modalities, such as annotation marks, text, audio, ink strokes and hyperlinks. In order to maintain the annotations context, i.e., to maintain the association between a note and the corresponding video feature, graphical video annotations can be combined with motion tracking algorithms. In addition, the system enables different modes of annotation and video visualization. The evaluation was made by international dance performers. I worked in the development, interaction design and evaluation of the Creation Tool.

Previous Research

mEmLearn (Winner of the HP Technology for Teaching Grant Initiative 2006)

The mEmLearn project departed from the VideoStore framework to support Tablet PCs. This project had the aim to define tools that enable students to augment the course materials in an interactive way, during or after the classes, to retrieve these materials at a later stage and to share them with other students or instructors. The system includes a Web drawing interface that allows students to annotate and share course materials with the Pen-based technology. I implemented the system prototype (Adobe Flash/Actionscript3) that enables pen-based video annotations, using Tablet PCs.


The main goal of the VideoStore project was to develop a Web based learning system, which enables to store, annotate and share video content. The prototype included: synchronized video with slides (MS Producer 2003); different video interfaces, such as mosaic, videoSpot and (streaming) log analyzer; video annotations; slides thumbnail interface; automatic video and slides editing for podcast.The project combined video streaming, video editing with Microsoft Media Format SDK, XML, PHP and JavaScript. The evaluation was made by Computer Science master students. I developed the system and its interfaces and planned the prototype evaluation.


Conference Proceedings

- Silva, J., Cabral, D., Fernandes, C., and Correia, N. Real-Time Annotation of Video Objects on Tablet Computers. In Proceedings of the 11th International Conference on Mobile and Ubiquitous Multimedia (MUM ’12), ACM, 2012, pp. 19:1-19:9.

Cabral, D. and Correia, N. VideoInk: A Pen-based Approach for Video Editing. In Adjunct proceedings of the 25th annual ACM symposium on User interface software and technology (UIST Adjunct Proceedings’12 ), ACM, 2012, pp. 67-68. (Cambridge,MA,USA).

Cabral, D., Valente, J. G., Aragão, U., Fernandes, C., and Correia, N. Evaluation of Multimodal Video Annotator for Contemporary Dance. In Proceedings of the 11th International Working Conference on Advanced Visual Interfaces (AVI ’12), ACM, 2012, pp. 572-579. (Capri, Italy)

Cabral, D., Valente, J., Silva, J., Aragão, U., Fernandes, C., and Correia, N. A Creation-Tool for Contemporary Dance using Multimodal Video Annotation. In Proceedings of the 19th ACM international conference on Multimedia (MM ’11), ACM, 2011, pp. 905-908. (Scottsdale, AZ, USA)

Cabral, D., Carvalho, U., Silva, J., Valente, J., Fernandes, C., and Correia, N. Multimodal video annotation for contemporary dance creation. In Proceedings of the 2011 annual conference extended abstracts on Human factors in computing systems (CHI EA ’11), ACM, 2011, pp. 2293-2298 (Vancouver, B.C., Canada) [pdf]

- Cabral, D., and Correia, N., Pen-based Video Annotations: a Proposal and a Prototype for Tablet PCs. 12th IFIP TC 13 International Conference on Human-Computer Interaction: INTERACT ’09 (Part II), vol. 5727 of Lecture Notes in Computer Science, Springer, 2009, pp. 17-20. (Uppsala, Sweden) (@googlebooks)

- Cabral, D., and Correia, N., Mobile and Web Tools for Participative Learning. International Conference on e-Learning IADIS 2007, IADIS, 2007, pp. 483-490. (Lisbon, Portugal)

Cabral, D., and Correia, N., An Environment for Mobile Learning Supporting Video Lectures and Annotations. International Conference on Mobile Learning IADIS 2007, IADIS, 2007, p. 290. (Lisbon, Portugal)

- Correia, N. and Cabral, D.Interfaces for Video Based Web Lectures. The 6th IEEE International Conference on Advanced Learning Technologies: ICALT 2006, IEEE, 2006, pp. 634-638. (Kerkrade, Netherlands)

- Correia, N. and Cabral, D.VideoStore: A system to store, annotate and share video based content. The 3rd International Conference on Multimedia and ICTs in Education: m-ICTE2005, Formatex, 2005, pp. 1299-1303.

Invited Poster/Demo Presentations

- Pen-based Multimedia Interfaces. Ciência 2010 – Meeting with Science – Portugal, Lisbon, Portugal, July 4-7, 2010.

- mEmLearn: Tools for Storing, Retrieving and Sharing Multimedia Learning Materials. First HP Technology for Teaching EMEA (Europe, Middle East and Africa) Regional Higher Education Forum, Imperial College, London, UK, October 10, 2007.

- mEmLearn: Tools for Storing, Retrieving and Sharing Multimedia Learning Materials. 2007 HP Technology for Teaching Worldwide Higher Education Conference, Monterey, CA, USA, February 7-8, 2007.


- Cabral, D. Mobile and Web Tools for Participative Learning. MSc Thesis, November, 2008.

Technical Reports

- Cabral, D. and Valente, J. Programmer’s Guide for QT Gui + openFrameworks (OF) in C++ (Visual Studio 2008 & 2010). CITI and DI, FCT/UNL, October, 2011.

Comments are closed.