Designing an algorithm - from ideas to code

I had always been interested in solving sudoku puzzles, partly because there are too many combinations that make each Sudoku unique. Since my work involves writing and using programming in different scenarios, I thought why not try using my skills on Sudoku. So there I was on a London Underground train to Barbican - looking at a Sudoku puzzle at the back of a morning newspaper, wondering how I can write an algorithm to solve it. I figured out a few simple tricks that I have always used in algorithm design. Here I explain what thoughts I had while designing my very own Sudoku solver and how I transformed those ideas into a working prototype.

First of all lets have a look at a typical Sudoku puzzle and some basic rules:

Sudoku Puzzle

Yes - it has got everything to do with numbers!! lots of numbers!

A Sudoku puzzle typically has 81 boxes where each box can have a number between 1 to 9. However, all these boxes follow some rules that make it all interesting. You may have noticed 3x3 squares grouping the number boxes. A correct solution of Sudoku ensures no repetition of numbers from 1 to 9 inside each of the 3x3 squares, in each horizontal line and each vertical line. When solving a Sudoku puzzle, this is exactly where I look for a solution, and exactly where my thought process starts for my Sudoku solver algorithm.

Long Exposure Shots with a GoPro and Matlab

I recently got  a GoPro. You know to get cool selfies, videos and all :D I am very much impressed by all the cool things you can do with it but was specifically impressed by the fact that one can create a time lapse video.

After giving a couple of tries to time lapse videos, I wanted to go beyond. I had always seen photographers make a long exposure shots by using specific DSLR cameras. I wanted to create just that using the only camera I had, a GoPro. However I had something much more than the camera, I knew how to write a code that deals with a number of images (I am a Computer Vision Engineer).

FFMPEG: Convert an image sequence to a compressed video

Just putting this here for my future self and anyone out there who might need to converts an image sequence into a video.

I have been using the following code to generate compressed videos from a big image sequence. It seems to have a really good balance between quality and compression.

ffmpeg -r 30 -f image2 -i out_%05d.png -vcodec libx264 -crf 25  test.mp4

Source:
http://hamelot.co.uk/visualization/using-ffmpeg-to-convert-a-set-of-images-into-a-video/ 

Different types of Randomness..

Randomness is an integral part of a number of programming algorithms. In fact most of my research until now has been based on a computer algorithm that only uses random numbers for learning a specific task.

A while back I was trying to write some code to define and visualize different Random number generation models. For this task I was playing with a number of different algorithms and visualizing the output on a (kind of a ) probability map. [Not to mention that I use OpenCV for this project as well].

Some of these maps looked pretty cool, so I am just embedding them in this post - also if anyone is interested I have shared the link to this project at the bottom of this post, check that and modify --> make your own random distributions :D

So the input to each of my functions is a Uniform Distribution which looks like this:

A 2D Uniform Distribution

"Welcome to the Virtual World...may I take your username?"

Quick note: I wrote this a long time back, but never published - thought it wasn't good enough. This just occurred to me --> it's just a post - doesnt need to be perfect right?!? So posting this now - Please be sure to leave a comment with what you think!

Over the last few years, there have been some amazing advancements in gadgets - specifically the new imaging devices have emerged and a new horizon for virtual reality has been set. These devices have opened up a door for limitless future development possibilities. "Occulus Rift", the virtual reality head-mounted device that was received with overwhelming Kickstarter response, has been the pioneer in developing the key tech that can realise the virtual reality. The reason behind this huge success is an amazing idea which transfers all your senses into a digitally created world. Although this concept has been recently recognised, the idea has been around for decades.