Let's try to apply our learning from this chapter and create a simple application for detecting a Sudoku grid in an image. You see Sudoku puzzles every day in newspapers or magazines; sometimes they provide a solution and sometimes they don't. Why not build an application for your mobile phone that can click a picture of the Sudoku, analyze the numbers, run some intelligent algorithms to solve the puzzle, and within seconds, you have the solution on your mobile screen.

After reading this chapter, we can easily work on the first part of the application; that is, localizing (detecting) the Sudoku grid from an image. As you read through this book, you will come across algorithms and techniques that will help you build the other parts of this application.

Let's break down our problem statement into subproblems and work each one out to have a fully functioning Sudoku localizing application: