Sudoku Solver or How to solve Sudoku from its pic | Part 0

Hi.
Its been a while since we made any post. Well, nothing held our attention long enough can be the excuse. There were games to complete, tournaments to win lose, fests to perform in, lots of series to watch, and exams to appear for. Bob Dylan said that "the answer, my friend, is blowing in the wind", and likewise to look for our answers, we changed our direction with the wind and kind of lost track of time. Coming straight to the point, we once thought of making some weekend project, things that take just a weekend to complete. However, we were so lazy in the weekends that nothing happened, and we ended up executing the project in our weekdays.

Allow me to explain the motivation behind our work. Sudoku were a craze this semester. Most in the class survived the onslaught of sleep in the lectures by solving Sudoku puzzles that come daily in the newspaper. However, the issue was sometimes we got stuck and would enter denial of service mode, where we ceased to respond to the outer world. We could use a little hint. However, we needed to wait a whole day for the solution to come. Therefore, we come up with the idea of implementing a solver, to which we feed the image of the puzzle and in turn, it returns the solution.

Now, I will walk you through the steps involved.

The image of the Sudoku is

After converting to grayscale and thresholding,

Then, get the area of interest, i.e the grid

Crop the original image to get the puzzle only

After some cleaning, it will look like

Then, the digits are segmented and identified

Last, the puzzle is solved

Technologies used are MATLAB and Python. All the above steps except the last are carried out by a MATLAB script, and the last is done by a python script.

This is the basic working model. We still need to handle rotation and skewness due to perspective. Also, better recognition algorithms are to be used. 

In the subsequent posts we will talk about our approach in detail.