# And now… Bitcoins!

The concept of the Bitcoin is still a bit mysterious for me. The idea seems fair in a general view; however, the use of it is what worries me.

Of course, when you’re using electronic means to do your transactions, you can always have a bug or something that suddenly fucks it up. I don’t want to rely my entire income in some virtual payment. Continue reading

# A fancy visualization of planes intersecting – Part 3 (and Final)

The mystery is over! From the previous posts we have seen the way we can generate a random plane, and visualize 3 of them at the same time showing their intersecting point.

It might be enough for some simple visual purposes, but we are more ambitious than that and we want to get it fancier.

And that’s why I’m here! This final step would be to achieve a neat visualization of our three planes and even the equations involved. Let’s begin with what we have so far:

```P = rand(3);
d = rand(3,1);
x = P\d;
hold on
drawPlane(P(1,:), d(1))
drawPlane(P(2,:), d(2))
drawPlane(P(3,:), d(3))
scatter3(x(1), x(2), x(3))```

Where the function drawPlane was defined as:

```function drawPlane(P, d)
[x, y] = meshgrid(-10:10);
z = -(1/P(3))*(P(1)*x + P(2)*y - d);
surf(x, y, z);```

# A fancy visualization of planes intersecting – Part 2

All right, I know I let you abandoned for a bit. But the last trip to Barcelona and the ongoing final exams in the University haven’t given me any chance to keep this. But I’m gonna take some minutes to finally write about the visualization of our planes.

In the last post we analyzed how a plane is constructed given the equation ax+by+cz = d. Then, given the parameters of this equation, I showed you how to generate its corresponding plane in Matlab.

Now I’m gonna keep this post short (sorry for the inconvenience), but here we are going to set 3 planes in a single visualization. In a third post, we’ll make all pretty and fancy.

# A fancy visualization of planes intersecting – Part 1

Well, it might not be the fanciest thing in the world but it surely looks good when you try to visualize your data. You know me, I always graph whatever I do, otherwise I don’t get many ideas. I have to see what is going on, and perhaps are many people like me.

This time I’m gonna share a very simple and nice way to visualize the solution of a linear equation system with 3 unknowns and 3 equations. Continue reading

# How to use polyval

One of the easiest and most useful tools in Matlab is polyval, a very nice function that evaluates a polynomial function given its parameters and the range to evaluate… huh? All right, all right, we wanna be clear here, right?

Suppose we are given a polynomial function, let’s say:

$f(x) = 3x^3 + 4x + 2$

and we would like to represent it in Matlab like that. Well, we cannot just write it like that. Remember Matlab is a numerical computation programm, which means, that it won’t compute any symbol. So forget it if you wanna computate something writting letters. Matlabs wants only numbers. You might put names to the variables, but still, Matlab computes only with numbers.

Now, what to do? There’s where our great friend polyval comes to the rescue! Continue reading

# The best Octave tutorial

Yes, as the title says, the best Octave tutorial out there is the one made by Professor Andrew Ng from Stanford. He started his world-famous Coursera almost two years ago. Now is one of the most successful companies in the world, why? Because it really gives what it promises and more: makes you understand Science.

Well, well go deep on it by yourself. These videos down are one of the first videos that Profr. Ng made for the course “Machine Learning”. I took it a year ago in its original website ml-class.org and it amazed me. I understood everything and didn’t have to smash my head to do so.

One of the chapters of his class was about handling Octave, the best free substitute for Matlab. Are you eager to master these computing tools? Dive into Octave next to Professor Ng. I promise you will be also amazed by the clear and concise way he teaches. This, my dear people, is the best Octave tutorial ever:

Part 1:

# Visual Navigation for Flying Robots

Free lectures! Free courses on-line! Free! Free!

Got your attention? I’m like spam.

So far, so good. It has been a year since I decided to get fully involved in this field of Computer Vision, and hasn’t been easy, but I gotta say it is full of surprises. My University has been strongly doing some research about it, and a proof of that is that the 3D Computer Vision course given in Coursera is actually done by a Professor in my university (tho in German). So, I think we’re moving quite strong.

My curiosity took me to the Computer Vision chair of the Informatics Department at the TUM and I think this semester they completely got me, as I’m planning to get the 3 lectures given there: Visual Navigation for Flying Robots, Multiple View Geometry and Machine Learning for Robotics and Computer Vision. Robotics, Machine Learning and Computer Vision! Makes my mouth water. Huh! Beautiful. Continue reading

Not sure if a late Easter egg, a passing joke or a permanent feature (would be fun), but Google gives us again the opportunity to play around with the common things on the internet.

This time comes all through Youtube. A new feature was added to the player of Youtube: the “Tape Mode”. You click it and your image will seem like an old VHS-cassette-like video. Quite nostalgic, I would say. I just discovered it watching some Ellen videos (I admit it, goddamit, that woman’s jokes are funny for me), and discovered this one with Steve Carell (better if you watch it in Youtube‘s website):

The legend says that they do it because of the 57th Anniversary of the commercial realease of the first VHS cassette. Well, quite a random number for me, but anyways. Not all videos have this feature. Apparently you just have to randomly find them too. Buuuu!!

Oh yeah, click “Pause” and it will keep the old effect of the cassette. These hipsters are everywhere with the electronic vintage effects. First their instagram, now this. I don’t think is gonna last, but I’d activate it for fun only.

Find a nice video and give it a try!

# Festo and its biological inspiration

Many companies around the world are fascinated with natural selection, because there is no wider range of inspiration for technology than the nature itself. Machines, robots and software are being designed with a strong background in biological elements. It is not coincidence that terms like mouse, virus or bug are common in the thecnological field.

Festo is a german company whose main goal is to design and build actuators for the automation industry. They are one of the biggest in this field. However, the german engineering is challenging through Festo again, and the innovation lovers in the company created the Festo Bionic Lab, where they have a complete freedom to experiment with their creativity. What have they done? A field entirely made of biological immitation. Their creations may  deceive your eyes at first sight, but oh boy! They have nailed it. Let’s check their main robots (my favorites), just for you to have an idea what I’m talking about…

The Airacuda was the first project, released in 2006, and the big challenge was to create a system that could really be an underwater robot, behaving and moving as a real fish. It still seems quite “robotic” with no emphasis in its out-looks, but the engineering behind such an underwater systems has been a true innovation copying the fish.

# 3D Reconstruction of a face from a single image

I don’t know if scary, jaw-dropping or simply impressive, but it turns out that there is already an algorithm developed here in Germany by Professors Volker Blanz and Thomas Vetter, that reconstructs a face in 3D from one image. Yes! out of a single image!

Maybe it wouldn’t sound that amazing at first sight, but you have to think about all the possible applications. Besides identifications, you can entirely play around with the information out of peoples’ faces, prediction, tracking, augmented reality, medical procedures, etc.

Is it something new? No way! It was presented in the International Conference on Computer Graphics and Interactive techniques of 1999! That’s right, fella, 14 years ago!

But why nobody used this impressive technique? Well, my guess is, of course, because of the computation times of it. Yes yes, very good, looks great and reconstructs faces pretty good, BUT took 50 minutes to reconstruct a face.

But wait a second! It was 14 years ago, right? With slower computers. Certainly, according to their paper, they used an SGI R10000 processor, which at that time was as powerful as 250 MHz… Well, I think is time to try it again with our new multi-core processors at several GHz.

Is it still on development? Did the creators give up? Are they preparing some new surprises? Well, we don’t know; but so far I can say that this technique has tons of applications with the new devices focusing in computer vision applications.