How can we recognize textured objects under the assumption of planarity in images? OpenCV provides extensive support for this task, and helps with local feature extraction, fast approximative matching, and robust model fitting. This article describes a minimalistic detector based solely on OpenCV for all vision subtasks, and also offers pictures, videos, and the source code.

Autumn has arrived and Stockholm dresses itself in wonderful colors. The magnificient scenery is definitely worth a few pictures.

In 2012, KTH Stockholm offered an exchange fair for local students that want to go abroad. We organized a booth for Technische Universität München.

Given a hidden Markov model, we can use the Viterbi algorithm in order to compute the most likely sequence of latent states that produced a certain sequence of observations. Neat: the algorithm is sort of breadth-first search for a maximum in a certain perfect N-ary search tree.

Charming. Unbeatable. Inconceivable. So much to the concert at KTH in Stockholm on September 12, which featured a variety of enjoyable pieces and culminated in the overwhelming “Music for the Royal Fireworks” (G. F. Händel). A fantastic display of music and fireworks in the Borggården of KTH main campus in a chilly late summer night.

Technische Universität München divides the academic year into a summer semester and a winter semester. However, it is four periods instead of two semesters at KTH Royal Institute of Technology. Here is a glance at some of the implications that I can see.

Where to get a bike in Stockholm? Where to put the bike? And is it worth bicycling in Stockholm? While the practicalities are not easy to address, the efforts certainly pay out as a first trip indicates.

Time was ripe for me to migrate my Arch Linux installation from SysV to systemd. The transition was simple enough and turned out to be smooth in my case. There were not any troubles to be resolved. Furthermore, systemd made a very good first impression.

Why is the lecturer talking Swedish? Kursen är på svenska, förstås! I noted with some surprise that one of my courses is given in Swedish. It turned out to be a very welcome opportunity to listen to Swedish in a multi-modal setting.

Unfortunate for all those who have to exchange euro for Swedish krona: the krona has reached a 12-year high against the euro in August 2012. This is a rough 10% loss compared to last year.

Looking for a light-weight, space-efficient backup solution for your data on local machines and remote servers? Give rsnapshot a try: relying on existing toolchains, opting for convention over configuration, and simple customization for slightly trickier backup tasks.

Every Tuesday one can hear random shouting at 10 pm in Lappis, a big housing estate near Stockholms universitet and KTH Stockholm.

Fearsome clone troopers are patrolling the campus! What is happening on the campus of KTH Royal Institute of Technology in Valhallavägen?

Tyresta National Park is merely an hour away from Stockholm, and is mostly rocks, wood, water. A special feature is a large area that was flame-cut by a raging wildfire in 1999, now offering a rough and strange landscape.

Stockholm is said to have very clean water. Indeed, I can only agree. Clean, refreshing, and open to everyone: swimming in Stockholm’s waters is excellent. What a welcome contrast to the lukewarm dirty waters around Hong Kong.

Travelling from Munich to Stockholm by train seems to be a crazy idea at the very first glance. However, coming at a price of 39,- EUR and virtually no baggage limit, I chose to take a 21h train ride on me to Stockholm via Nürnberg, Hamburg and Copenhagen with Deutsche Bahn. While the crowded trains made the journey tougher than expected, I was surprised by getting a ferry-ride for both the Intercity Express and myself.

Wonder about the depths of C++? Wonder why the code you wrote yesterday no longer works in the morning? Olve Maudal stated on TNG Big Techday 5 in Munich that you ought to look under the hood when you want to understand more about C++. His key statements were: C++ is fast and powerful. Yet, a shark is always lurking in your back, so have an appropriate model in mind. I enjoyed the talk, for more about this, see Olve Maudal’s blog and the freely available slides on the topic.

How can we let a robot create a map of an unknown indoor environment using three cameras that simultaneously provide depth information and color images? We investigated this question in a four-week practical course at our university. This article sheds some light on the challenges involved.

The public parks in Shanghai attract lots of people, especially on Sundays. As described in a previous article, these parks offer plenty of opportunities for a variety of leisure activities. Actually, the People’s Park on People’s Square features the most curious of all the Sunday activities I have seen so far.

The city proper of Shanghai is home to 20 million inhabitants (see here and here). Unsurprisingly, despite of its density, the urban area goes on and on. Nevertheless, if people want to enjoy nearby green areas in their spare time, they have at least the public parks.

Taking the train is a common way of travelling in China and popular amongst locals and foreigners. Westerners might find some surprising facts about travelling in China by train.

Traffic in China follows other rules than in Germany. Also the assortment of vehicles in China is much more diverse; featuring trucks, buses, taxis, private cars, electric scooters, motorcycles, bicycles, three-wheeled cars and pedestrians all sharing the same space.

Tracking an object over a sequence of 2D images is a challenging task. One approach uses a linear mapping between observed intensity differences and target motion; this is presented in the paper Hyperplane Approximation for Template Matching by F, Jurie and M. Dhome. Here are some results from an implementation in Matlab by a fellow student and me.

Your wireless presenter is not working for prezi.com in full-screen mode? Here is how you might be able to fix the issue on X-based Linux desktops by temporarily remapping the “Page Up” and “Page Down” buttons of your keyboard.

A set of images that have some common overlapping regions can be stichted together to form a panorama picture. Some recent camera models can even compute the panorama picture internally and do not require post-processing on the computer. While this is a problem that has already been solved (for example, there is AutoStitch, here are some hints on classic DIY-panorama-stitching using Matlab, SIFT, DLT and RANSAC.