One of our engineers, David Plowman, describes machine learning and shares news of a Raspberry Pi depth estimation challenge run by ETH Zürich (Swiss Federal Institute of Technology).
Spoiler alert – it’s all happening virtually, so you can definitely make the trip and attend, or maybe even enter yourself.
What is Machine Learning?
Machine Learning (ML) and Artificial Intelligence (AI) are some of the top engineering-related buzzwords of the moment, and foremost among current ML paradigms is probably the Artificial Neural Network (ANN).
They involve millions of tiny calculations, merged together in a giant biologically inspired network – hence the name. These networks typically have millions of parameters that control each calculation, and they must be optimised for every different task at hand.
This process of optimising the parameters so that a given set of inputs correctly produces a known set of outputs is known as training, and is what gives rise to the sense that the network is “learning”.
A popular type of ANN used for processing images is the Convolutional Neural Network. Many small calculations are performed on groups of input pixels to produce each output pixel
Machine Learning frameworks
A number of well known companies produce free ML frameworks that you can download and use on your own computer. The network training procedure runs best on machines with powerful CPUs and GPUs, but even using one of these pre-trained networks (known as inference) can be quite expensive.
One of the most popular frameworks is Google’s TensorFlow (TF), and since this is rather resource intensive, they also produce a cut-down version optimised for less powerful platforms. This is TensorFlow Lite(TFLite), which can be run effectively on Raspberry Pi.
Depth estimation
ANNs have proven very adept at a wide variety of image processing tasks, most notably object classification and detection, but also depth estimation. This is the process of taking one or more images and working out how far away every part of the scene is from the camera, producing a depth map.
Here’s an example:
The image on the right shows, by the brightness of each pixel, how far away the objects in the original (left-hand) image are from the camera (darker = nearer).
We distinguish between stereo depth estimation, which starts with a stereo pair of images (taken from marginally different viewpoints; here, parallax can be used to inform the algorithm), and monocular depth estimation, working from just a single image.
The applications of such techniques should be clear, ranging from robots that need to understand and navigate their environments, to the fake bokeh effects beloved of many modern smartphone cameras.
Depth Estimation Challenge
We were very interested then to learn that, as part of the CVPR (Computer Vision and Pattern Recognition) 2021 conference, Andrey Ignatov and Radu Timofte of ETH Zürich were planning to run a Monocular Depth Estimation Challenge. They are specifically targeting the Raspberry Pi 4 platform running TFLite, and we are delighted to support this effort.
For more information, or indeed if any technically minded readers are interested in entering the challenge, please visit:
The conference and workshops are all taking place virtually in June, and we’ll be sure to update our blog with some of the results and models produced for Raspberry Pi 4 by the competing teams. We wish them all good luck!
When we think back to our school days, we can all recall that one teacher who inspired us, believed in us, and made all the difference to how we approached a particular subject. It was someone we maybe took for granted at the time and so we only realised (much) later how amazing they were.
I hope this post makes you think of a teacher or mentor who has made a key difference in your life!
Here computer science student Jonathan Alderson and our team’s Ben Garside talk to me about how Ben supported and inspired Jonathan in his computer science classroom.
The teacher: Ben Garside. The student: Jonathan Alderson.
Hi Jonathan! How did you get into computing?
Jonathan: My first memories of using a computer were playing 3D Pinball, Club Penguin, and old Disney games, so nothing productive there…or so I thought! I was always good at IT and Maths at school, and Computing seemed to be a cross between the two, so I thought it would be good.
Jonathan and Ben, can you remember your time working together? It’s been a while now!
Jonathan: I met Mr Garside at the start of sixth form. Our school didn’t have a computer science course, so a few of us would walk between schools twice a week. Mr Garside really made me feel welcome in a place where I didn’t know anyone.
When learning computer science, it’s difficult to understand the importance of new concepts like recursion, classes, or linked lists when the examples are so small. Mr Garside’s teaching made me see the relevance of them and how they could fit into other projects; it’s easy to go a long time without using concepts because you don’t necessarily need them, even when it would make your life a lot easier.
Mr Garside really made me feel welcome in a place where I didn’t know anyone. […] Mr Garside’s teaching made me see the relevance of [new computer science concepts] and how they could fit into other projects.
Jonathan Alderson
Ben: It was a real pleasure to teach Jonathan. He stands out as being one of the most inquisitive students that I have taught. If something wasn’t clear to him, he’d certainly let me know and ask relevant questions so that he could fully understand. Jonathan was also constantly working on his own programming projects outside of lessons. During his A level, I remember him taking it upon himself to write a program that played chess. Each week he would demonstrate the progress he had made to the class. It was a perfect example of decomposition as he tackled the project in small sections and had a clear plan as to what he wanted to achieve. By the end of his project, not only did he have a program that played chess, but it was capable of playing against real online users including making the mouse clicks on the screen!
Moving from procedural to object-oriented programming (OOP) can be a sticking point for a lot of learners, and I remember Jonathan finding this difficult at first. I think what helped Jonathan in particular was getting him to understand that this wasn’t as new a concept as he first thought. OOP was just a different paradigm where he could still apply all of the coding structures that he was already confident in using.
That sounds like a very cool project. What other projects did you make, Jonathan? And how did Ben help you?
Jonathan: My final-year project, [a video game] called Vector Venture, ended up becoming quite a mammoth task! I didn’t really have a clue about organising large projects, what an IDE was, or you could split files apart. Mr Garside helped me spend enough time on the final report and get things finished. He was very supportive of me releasing the game and got me a chance to speak at the Python North East group, which was a great opportunity.
Ben: Vector Venture was a very ambitious project that Jonathan undertook, but I think by then he had learned a lot about how to tackle a project of that size from previous projects such as the chess program. The key to his success was that whilst he was learning, he was picking projects to undertake that he had a genuine interest in and enjoyed developing. I would also tell my A level students to pick as a project something that they will enjoy developing. Jonathan clearly enjoyed developing games, but I also had students who picked projects to develop programs that would solve problems. For example, one of my students developed a system that would take online bookings for food orders and manage table allocation for a local restaurant.
I would tell my A level students to pick as a project something that they will enjoy developing.
Ben Garside
I think that point about having fun while learning something challenging like programming is really important to highlight. So what are you doing now, Jonathan?
Jonathan: I have just completed my undergraduate degree at the University of Leeds (UoL) with a place on the Dean’s List and am staying to complete a Masters in High Performance Graphics.
During my time at UoL, I’ve had three summer placements creating medical applications and new systems for the university. This helped me understand the social benefits of computer science; it was great to work on something that is now benefitting so many people. My dissertation was on music visualisation, mapping instrument attributes of a currently playing song to control parameters inside sharers on the GPU to produce reactive visualisations. I’ve just completed an OpenGL project to create procedural underwater scenes, with realistic lighting, reflections, and fish simulations. I’m now really looking forward to completing my Game Engine project for my masters and graduating.
Teachers are often brilliant at taking something complicated and presenting it in a clearer way. Are those moments of clarity part of what motivates you to teach, Ben?
Ben: There are lots of things that excite me about teaching computer science. Before I worked for the Raspberry Pi Foundation, there was a phrase I heard Carrie Anne Philbin say when I attended a Picademy: we are teaching young people to be digital makers, logical thinkers, and problem solvers, not just to be consumers of technology. I felt this really summed up how great it is to teach our subject. Teaching computer science means that we’re educating young people about the world around them and how technology plays its part in their lives. By doing this, we are empowering them to solve problems and to make educated choices about how they use technology.
Teaching computer science means that we’re educating young people about the world around them and how technology plays its part in their lives.
Ben Garside
As for my previous in-school experiences, I loved those lightbulb moments when something suddenly made sense to a student and a loud “Yesssss!” would break the silence of a quietly focused classroom. I loved teaching something that regularly sparked their imaginations; give them a single lesson on programming, and they would start to ask questions like: “Now I’ve made it do that…does this mean I could make it do this next?“. It wasn’t uncommon for students to want to do more outside of the classroom that wasn’t a homework activity. That, for me, was the ultimate win!
How about you?
Who was the teacher who helped shape your future when you were at school? Tell us about them in the comments below.
We’re pleased to share that Dr Sue Sentance, our Chief Learning Officer, is receiving a Suffrage Science award for Mathematics and Computing today.
The Suffrage Science award scheme celebrates women in science. Sue is being recognised for her achievements in computer science and computing education research, and for her work promoting computing to the next generation.
Sue is an experienced teacher and teacher educator with an academic background in artificial intelligence, computer science, and education. She has made a substantial contribution to research in computing education in school over the last ten years, publishing widely on the teaching of programming, teacher professional development, physical computing, and curriculum change. In 2017 Sue received the BERA Public Engagement and Impact Award for her services to computing education. Part of Sue’s role at the Raspberry Pi Foundation is leading our Gender Balance in Computing research programme, which investigates ways to increase the number of girls and young women taking up computing at school level.
The awards are jewellery inspired by computing, mathematics, and the Suffragette movement
As Dr Hannah Dee, the previous award recipient who nominated Sue, says: “[…] The work she does is important — researchers need to look at what happens in schools, particularly when we consider gender. Girls are put off computing long before they get to universities, and an understanding of how children learn about computing and the ways in which we can support girls in tech is going to be vital to reverse this trend.”
Sue says, “I’m delighted and honoured that Hannah nominated me for this award, and to share this honour with other women also dedicated to furthering the fields of mathematics, computing, life sciences, and engineering. It’s been great to see research around computing in school start to gather pace (and also rigour) around the world over the last few years, and to play a part in that. There is still so much to do — many countries have now introduced computing or computer science into their school curricula as a mandatory subject, and we need to understand better how to make the subject fully accessible to all, and to inspire and motivate the next generation.”
Aside from her role in the Gender Balance in Computing research programme, Sue has led our work as part of the consortium behind the National Centre for Computing Education and is now our senior adviser on computing subject knowledge, pedagogy, and the Foundation’s computing education research projects. Sue also leads the programme of our ongoing computing education research seminar series, where academics and educators from all over the world come together online to hear about and discuss some of the latest work in the field.
We are delighted to share the news that Carrie Anne Philbin, Raspberry Pi’s Director of Educator Support, has been awarded an MBE for her services to education in the Queen’s Birthday Honours 2020.
Carrie Anne Philbin, newly minted MBE
Carrie Anne was one of the first employees of the Raspberry Pi Foundation and has helped shape our educational programmes over the past six years. Before joining the Foundation, Carrie Anne was a computing teacher, YouTuber, and author.
She’s also a tireless champion for diversity and inclusion in computing; she co-founded a grassroots movement of computing teachers dedicated to diversity and inclusion, and she has mentored young girls and students from disadvantaged backgrounds. She is a fantastic role model and source of inspiration to her colleagues, educators, and young people.
From history student to computing teacher and YouTuber
As a young girl, Carrie Anne enjoyed arts and crafts and when her dad bought the family a Commodore 64, she loved the graphics she could make on it. She says, “I vividly remember typing in the BASIC commands to create a train that moved on the screen with my dad.” Being able to express her creativity through digital patterns sparked her interest in technology.
After studying history at university, Carrie Anne followed her passion for technology and became an ICT technician at a secondary school, where she also ran several extra-curricular computing clubs for the students. Her school encouraged and supported her to apply for the Graduate Teacher Programme, and she qualified within two years.
Carrie Anne admits that her first experience in a new school as a newly qualified teacher was “pretty terrifying”, and she says her passion for the subject and her sense of humour are what got her through. The students she taught in her classroom still inspire her today.
Showing that computing is for everyone
As well as co-founding CAS #include, a diversity working group for computing teachers, Carrie Anne started the successful YouTube channel Geek Gurl Diaries. Through video interviews with women working in tech and hands-on computer science tutorials, Carrie Anne demonstrates that computing is fun and that it’s great to be a girl who likes computers.
On the back of her own YouTube channel’s success, Carrie Anne was invited to host the Computer Science video series on Crash Course, the extremely popular educational YouTube channel created by Hank and John Green. There, her 40+ videos have received over 2 million views so far.
Discovering the Raspberry Pi Foundation
Carrie Anne says that the Raspberry Pi computer brought her to the Raspberry Pi Foundation, and that she stayed “because of the community and the Foundation’s mission“. She came across the Raspberry Pi while searching for new ways to engage her students in computing, and joined a long waiting list to get her hands on the single-board computer. After her Raspberry Pi finally arrived, she carried it in her handbag to community meetups to learn how other people were using it in education.
Carrie Anne with her book Adventures in Raspberry Pi
Since joining the Foundation, Carrie Anne has helped to build an incredible team, many of them also former computing teachers. Together they have trained thousands of educators and produced excellent resources that are used by teachers and learners around the world. Most recently, the team created the Teach Computing Curriculum of over 500 hours of free teaching resources for primary and secondary teachers; free online video lessons for students learning at home during the pandemic (in partnership with Oak National Academy); and Isaac Computer Science, a free online learning platform for A level teachers and students.
On what she wants to empower young people to do
Carrie Anne says, “We’re living in an ever-changing world that is facing many challenges right now: climate change, democracy and human rights, oh and a global pandemic. These are issues that young people care about. I’ve witnessed this year after year at our international Coolest Projects technology showcase event for young people, where passionate young creators present the tech solutions they are already building to address today’s and tomorrow’s problems. I believe that equipped with a deeper understanding of technology, young people can change the world for the better, in ways we’ve not even imagined.”
Carrie Anne has already achieved a huge amount in her career, and we honestly believe that she is only just getting started. On behalf of all your colleagues at the Foundation and all the educators and young people whose lives you’ve changed, congratulations Carrie Anne!
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