What I Learned in the MotorBoat Lessons in Switzerland

In the summer of 2023, I got my Swiss motorboat license in Zurich. I trained for it also in Zurich. I have also written a blog post in the past, about how to get a Swiss motorboat license. While on the surface it might seem like driving a boat is the same as a car. … Continue reading What I Learned in the MotorBoat Lessons in Switzerland →

Spatial Angular Velocity vs Body Frame Angular Velocity

A while ago I had written about IMU pre-integration (blog-link). Particularly, I had played around with the inertial measurements data (IMU data) and tried to dig a bit deeper on what exactly does the IMU measurements mean. So the conclusion was that the IMU measure the body frame angular velocity and body-frame angular velocity (and … Continue reading Spatial Angular Velocity vs Body Frame Angular Velocity →

How to get a Motorboat License in Switzerland

Going around Switzerland, it is hard to miss its beautiful lakes. This summer (2023) I was fortunate enough to have figured out the process and obtained my boating licenses in Switzerland. In this blog post, I will share with you the process I went through to obtain one. I generally found very little information about … Continue reading How to get a Motorboat License in Switzerland →

IMU Preintegration Theory

A while ago, I had explored the theory of IMU preintegration in the context of sensor fusion using a factor graph. The basic concept is that to use imu measurement as between factors for optimization we need to know the previous state. This is not convenient, however, a mathematical trick helps us make the between … Continue reading IMU Preintegration Theory →

Lost Wax Casting – 2

The year 2020 turned out to be a year of COVID. My flights to back home in Dec 2020 got cancelled. So spend a part of the holiday to take my art of casting a bit further. In the end, I could have a ring made out of brass. Carrying forward the experience from last … Continue reading Lost Wax Casting – 2 →

MAP and MLE : Relation to Least Squares

Estimation of parameters is a central problem in various fields of applied science. In robotics and machine learning, literally a good solution to a problem is cast as an optimization problem of some sort. This optimization problem involves a some observations, residue function and some optimization variables (this exact process is sometimes also referred as … Continue reading MAP and MLE : Relation to Least Squares →

Marginalization vs Conditioning for Multivariate Gaussian Distribution

Gaussian distribution have these nice property that under linear transformation the resulting distribution is still a Gaussian distribution. This property is successfully exploited by the Kalman Filter. In a previous post I had explored the details of Extended Kalman Filter. Today I am exploring the intuitive meaning of Marginalization vs Conditioning for Gaussian distributions. It … Continue reading Marginalization vs Conditioning for Multivariate Gaussian Distribution →

Lost Wax Casting

In Jan 2020, right after my Ph.D. defense I set my sights on lost wax casting for jewellery. It was a great learing experience for me as it was something totally new to me. Some things I learnt, during the 3 weeks I spent doing this are: I started out by buying some plaster of … Continue reading Lost Wax Casting →

Linearization of Vector Valued Function

We often come across a vector valued function which needs linearization. Depending on the form though, doing it manually is very tedious and prone to error. In this post, let us try to use a computer algebra system, maxima and try to get a linear approximation of a vector valued function. Basic Theory The principle … Continue reading Linearization of Vector Valued Function →

Sensor Fusion: Extended Kalman Filter (EKF)

Overview In this post I am going to briefly tell you about Kalman filter and one of its extensions to non-linear cases, ie. the Extended Kalman Filter (EKF). I will give a concrete example from Robotics on sensor fusion of IMU measurements and Odometry estimates from other SLAM algorithm. In robotics literature, this is referred … Continue reading Sensor Fusion: Extended Kalman Filter (EKF) →