Welcome to uavster's blog (filtered)

You are currently browsing posts related to Tutorials. Perhaps you prefer to browse all posts.

Boosting color-based tracking

Tracking an object over a video sequence is a classic problem in Computer Vision. A tracking algorithm looks for the object at every new frame, given a model of the object. This model holds information [...]

There are tons of tutorials on color-based tracking that use the histogram back-projection to find those pixels in the image that are most likely to be object pixels. Then, they use MeanShift [...]

After normalization, each bin value in the color histogram expresses the probability that a pixel has a color in bin B, given that it is a pixel of object O. We can express this as the conditional probability [...]

Computer VisionOpen SourceTutorials... Technologies: OpenCVC++

Measuring heart rate with a smartphone camera

There are some apps out there that can read your heart rate with a smartphone camera. No need for external pulsometers. The procedure is simple: you press the smartphone camera lens gently with your finger [...]

It is time to open your photo app and observe what happens when you cover the camera with your finger. The frame is not black but slightly red. The ambient light is traveling through your finger tissues [...]

The experiments in this post were done offline. I recorded the videos with an iPhone 4S and copied them to my laptop. Then, I processed them with Matlab. The full code is available here [...]

Computer VisionTutorialsSignal processing Technologies: iPhoneMatlabFast Fourier Transform

Attitude estimation on iPhone

Stand up and close your eyes. If you have superpowers and managed to memorize this text before doing so, you'll be now reading it in your mind. Now, try to walk straight for two meters towards somewhere [...]

In order to know their spatial orientation and keep balance, robots use Inertial Measurement Units (IMU). They are composed of accelerometers, gyroscopes and, sometimes, magnetometers that measure linear [...]

Thanks to MicroElectroMechanical Systems (MEMS), the components in an IMU today can be embedded into chip-like casings and consume very low power. This opened the door some years ago to the inclusion of [...]

Autonomous RoboticsTutorialsState estimation... Technologies: OpenCViOSiPhone...

Getting started with Computer Vision on iPhone

I still remember my first mobile phone back in 1998. It was an Alcatel One Touch Easy. You could do thousands of things with it: calling your parents, calling your girlfriend, calling your friends, calling [...]

Ok, let's get serious. Needless to say, today's smartphones are orders of magnitude more powerful than my old Alcatel thanks to Moore's law. In fact, they are becoming powerful enough to execute [...]

Since a few months ago, I had programmed computer vision software for desktop machines and laptops. I always thought of trying with Android or other mobile operating system, but never had time to really [...]

Computer VisionTutorialsExperiments Technologies: LinuxOpenCViOS...