For reasons I do not recall the Geo-Walks have always been on weekdays. So, the next Amsterdam Geo-Walk is on Saturday 15 November, starting at 10:00. The main characters are father & son Blaeu, and Mayor Hudde, with cameos of Descartes and Huygens. You can sign up at www.skool.com/amsterdam-ge...

It is election night here in the Netherlands. We voted today for the members of parliament in the Second Chamber. It is quite unpredictable this time. I always enjoy looking at the people behind the reporter at the gatherings of the political parties. As an amateur anthropologist.

Deze info heb ik nu even nodig. Dank Steeph!

As a citizen of Amsterdam, I was invited to celebrate its 750th anniversary in City Hall on Dam Square. I was mainly interested in the 6.24-meter-diameter floor maps by Joan Blaeu in the Burgerzaal. I made a cameo appearance during an interview for local news channel AT5. I am the man in blaeu.

The Royal Palace Amsterdam is probably the only building in the city that is exactly aligned with the cardinal directions. Strangely satisfying.

Natural Perspective is an approach that basically ignores the optical projection. Euclid called it 'visual cone’ (300 BC). Gibson later called it 'visual solid angle’ (1986). I apply Rational Trigonometry (Wildberger 2005) and get pleasantly simple expressions. youtu.be/9qCtaVkFZsI

In the 7th and final session today I gave a summary of the theory of vision I am developing. I realised I have shared many partial results but have never given a overview of all the steps in the vision process. If you want to join me on this adventure, sign up at www.skool.com/geometric-vi...

Why is Descartes' name synonymous with mind-body dualism, why was he so convinced by this theory, and how did he explain vital activities in the body if there is no "soul"? Find out the answers on today's new podcast: www.historyofphilosophy.net/descartes-du... #hopwag #philsky #descartes #mind

If you are interested to learn more, you can join www.skool.com/amsterdam-ge...

@rmathematicus.bsky.social thank you for being a source of inspiration for this!

I am getting ready for the first Amsterdam Geo-Walk of the season. It is a guided tour around 17th century Amsterdam with geography and geometry as its main themes. This week I have 16 participants which is more than I am used to.

The fundamental problem of human visual perception; eyes & brains measure visual directions and visual angles, but we need to know object dimensions & shape, positions, and attitudes.

In the 5th session today I discussed some of the computer vision systems that I have developed. One nice result is that I determined the height of the National Monument on Dam square in Amsterdam from a photograph taken by a drone. You can still join for free at www.skool.com/geometric-vi...

Today was the 4th of 7 sessions and I have addressed the core topic of my research: visual objects. If you want to follow along, you can still join for free at lnkd.in/e4UsJjFr

We love the retina. A tractable brain. Learn how it works and you understand infinitely more about the rest of the nervous system. This structural image - <chefs kiss>

René Descartes mechanics and cosmology #histsci thonyc.wordpress.com/2025/09/17/f...

Below you can see me gesturing that my new method for finding the focal length of a camera is really close to the classic result. I have derived a simple formula for the focal length of a camera from the elliptical projections of spheres only.

The 2nd video for my Skool channel is on geometry. I applied Rational Trigonometry created by Wildberger to derive simple expressions for what Euclid called 'visual cones' and Gibson called 'visual solid angles'. You can see that I am looking up to them.

Everything went smoothly while re-recording the 1st video for my Skool channel. Except for claiming that vision is fundamentally simple, I also talked about cognitive models and argued that future AI needs explicit visual world models.

I have been recording the first video for my Skool channel today. It turned out that the 🎤was not properly connected. So, I practiced recording my first video today.

I opened my own school. Below is an invite to a free private online community on the theme of geometric vision. For those who can join, I will give a first course on my research results every Wednesday over the next 7 weeks. Check it out via www.skool.com/geometric-vi...

Unless Wikipedia's translation is wrong it is literally in the 1st postulate of Euclid’s Optics: Let it be assumed 1. That rectilinear rays _proceeding from the eye_ diverge indefinitely.

The fundamental problem of vision; we measure directions and angles, but we want to know distances and dimensions.

Made today a tour along some of the scientific highlights of Amsterdam. Well hidden, but if you know where to look (thanks @stijnoomes.bsky.social )

Here is a wide ranging conversation Salim Baidoun and I had at TomTom HQ about many things GIS-related. open.spotify.com/episode/2a8d...

My obituary of Henk Bos, who opened the eyes of so many of us to the history of mathematics: research-portal.uu.nl/ws/portalfil...

Vandaag Open Dag op het Science Park, voor alle aanstaande studenten. Het Dutch Nao Team is nu op de RoboCup German Open, maar de wedstrijden worden live gestreamd.

This academic year I have mainly been teaching Geographic Information Systems and Deep Learning / Computer Vision. I feel GIS is greatly underrated though it is working exceptionally well, deeply rooted in science. DL on the other hand is annoyingly overhyped and flimsy at best.

My confusion about Prime Target (I have watched up until S1 E6) is that mathematician Edward Brooks has not solved the problem yet. So why are they after him?

Shall I watch a TED-talk? Nâh, I don’t have the patience for an 18-minute sermon. Let me listen to a 3-hour podcast instead.

If you see this, post a picture with no explanation.

Very happy to announce that I have rediscovered Processing. For some of my needs it helps me to escape the configuration hell of Jupyter Notebooks.

This is a fascinating history, very well presented.

Computer Vision: Fact & Fiction is now available on YouTube 🙌🏼 I made a playlist for it with the seven chapters. Enjoy this time capsule from two decades ago!

@flipphillips.com I am watching Franklin on 🍎+. Did this happen in your backyard?

With his first book, Mysterium Cosmographicum published in 1596, the young Kepler set off on a live long journey to reveal the secrets of God's geometrical cosmos #histsci thonyc.wordpress.com/2024/12/27/c...

I am finally watching Oppenheimer. Let me just park my judgements on the science and the technology, and focus on the cinematic. What the f is wrong with telling a story in chronological order?

Earthrise. Taken #OTD 56 years ago. In terms of seeing that we're all on this one single planet, it's one of the most important photos ever taken.

So, here you are!