Today, we feature an interview with Pedro Martin, a PhD student in Electrical and Computer Engineering (PDEEC) and a researcher at the Instituto de Telecomunicações (IT). His research focuses on signal processing, particularly the compression and quality assessment of three-dimensional (3D) signals, an area that has given him the opportunity to participate in international conferences and collaborate with researchers from different institutions. However, his interests extend beyond scientific research. Together with a group of friends, he founded the Associação Cultural Imprevisto, an initiative that promotes debate and knowledge sharing among students from various universities in Lisbon. In this interview with DEEC, Pedro Martin discusses his academic journey, the challenges of pursuing a PhD, and the importance of broadening learning beyond the classroom.

3D signal processing plays a key role in a wide range of technologies, from surveying buildings and structures to developing virtual and augmented reality systems. However, the large volume of data typically involved requires efficient compression mechanisms to enable storage and transmission in real-world telecommunications systems. This need also gives rise to another challenge: understanding how compression algorithms affect the final signal quality.

This is the focus of Pedro Martin's research. Supervised by Professors Paula Queluz, João Ascenso and António Rodrigues, faculty members at DEEC and researchers at IT, his work centres on 3D signal processing, particularly compression and quality assessment.

His interest in this field within academia was fuelled by the development of an algorithm for 3D reconstruction, known as NeRF, published by Google in 2020. “There was a great deal of enthusiasm in academia, and we decided to start working on that topic,” he recalls. But what does research in this field actually involve?

Imagine that I want to create a replica of this room so I can send it to a friend in China, allowing them to understand the space where we are having this meeting [...] Our job is to take the 3D model of the space and compress it. [...] We then send the file to our friend, who decompresses it and can see the room in the appropriate quality.

Pedro Martin, PhD student in Electrical and Computer Engineering and researcher at IT

In practice, the process can be divided into several stages. First, photographs and/or videos of the space are collected, providing two-dimensional (2D) data. This information is then processed using an algorithm that reconstructs the room in three-dimensional (3D) form. This representation allows users to perceive the geometry and depth of the space. However, the resulting file becomes “too large” to send directly to the recipient. “We are talking about gigabytes. A photograph sent via WhatsApp is approximately 1 megabyte; 1 gigabyte is roughly the size of a full HD movie,” the student explains.

For this reason, the 3D file must be compressed before transmission and decompressed once it has been received. “One of our goals is to understand how a given message can be compressed without losing quality,” Pedro Martin explains.

One of the main challenges is preserving the quality of the signal, in other words, compressing it in such a way that this room remains recognisable as a room.

Pedro Martin, PhD student in Electrical and Computer Engineering and researcher at IT

In addition to developing algorithms, his research has led to the publication of several scientific papers. However, he identifies publishing as one of the greatest challenges he has faced during his PhD. “I won't hide the nervousness that comes with it,” he admits, acknowledging that not all papers are accepted following evaluation by scientific reviewers (peer review). Nevertheless, he highlights the opportunity he has had to publish several works, including the creation of a database associated with the paper NeRF-QA: Neural Radiance Fields Quality Assessment Database, which brought together the results of quality assessments of different 3D models. “Paradoxically, the simplest and shortest paper I wrote was one of the most widely recognised,” he recalls.

Scientific publishing has also enabled him to engage with the international research community. Among his collaborations, he highlights his work with the Joint Photographic Experts Group (JPEG), the group responsible for developing the standard that enables images to be compressed in JPEG format.

His research has also given him the opportunity to attend conferences and other scientific events in countries such as Belgium, Japan, Spain and Turkey.

It is always a privilege to attend conferences and present my work. It has been a very enriching experience for my PhD. I have met researchers from many other institutions, including those outside Portugal, and become more familiar with their work.

Pedro Martin, PhD student in Electrical and Computer Engineering and researcher at IT

Engaging with researchers from different institutions and scientific backgrounds has contributed not only to the development of his research but also to Pedro Martin's interest in science communication. This desire to share knowledge earned him an honourable mention at the PhD Open Days 2025. “It was above all a discovery I made about myself: I enjoy communicating all the research I do in a precise way,” he emphasises, adding that this is a skill he has continued to develop throughout his PhD.

Despite his involvement in research and the scientific community, pursuing a PhD was not part of his plans from the beginning of his academic journey.

Unlike most of my fellow PhD students, when I started this degree, I hadn't even considered doing a PhD. It had never been an option.

Pedro Martin, PhD student in Electrical and Computer Engineering and researcher at IT

Although he completed his entire academic journey at Técnico, it was only in the later stages of his studies that Pedro Martin began to reflect more deeply on the impact of academic research. “One of the criteria for choosing my degree was the idea that electrical engineering opened up many career opportunities. The decision to pursue a PhD only came during the final year of my master's degree,” he explains.

His decision to remain in academia was driven by two factors: his enjoyment of research, which emerged while working on his master's thesis, and the opportunity to continue supporting teaching activities as a teaching assistant in courses within the Electrical and Computer Engineering degree programme. “These two experiences were so meaningful that pursuing a PhD felt like a very natural next step,” he says. Since then, he has combined research with teaching. Looking ahead, he hopes to pursue a career related to teaching.

I really enjoyed teaching: being in a classroom with students and a professor, exploring a particular aspect of the world in greater depth. Since then, I have worked as a TA (Teaching Assistant) every year.

Pedro Martin, PhD student in Electrical and Computer Engineering and researcher at IT

For Pedro Martin, however, learning extends far beyond university education. Together with a group of friends, he also founded the Associação Cultural Imprevisto, where he continues to play an active role. The initiative organises exhibitions and talks covering a wide range of subjects, including health, economics, science and literature. These events are open to students from various universities in Lisbon, regardless of their prior knowledge of the subject. “Above all, we wanted to revive a certain concept of the university, understood as a place where professors and students share their interests and grow together by exploring the things they are passionate about, whatever they may be. As students, we felt a certain responsibility to put forward a public initiative in this spirit, one that was not confined to a single field of knowledge. We believe that everything is worth taking an interest in,” he explains.

Balancing research, teaching and cultural engagement, Pedro Martin emphasises the importance of making the most of opportunities to explore personal interests and develop new skills beyond the traditional classroom setting.

If I could leave a message for younger students, I would tell them to make the most of their university experience. This is the time to take our interests seriously, explore our passions to the fullest and become active participants in our own journeys. In practice, this is what ultimately yields the greatest benefits, both personally and professionally.

Pedro Martin, PhD student in Electrical and Computer Engineering and researcher at IT