Recognition of numbers and position using image processing techniques for solving Sudoku Puzzles

In this paper we propose a method of detecting and recognizing the elements of a Sudoku Puzzle and providing a digital copy of the solution for it using MATLAB. The method involves a vision-based sudoku solver. The solver is capable of solving a sudoku directly from an image captured from any digital camera. After applying appropriate pre-processing to the acquired image we use efficient area calculation techniques to recognize the enclosing box of the puzzle. A virtual grid is then created to identify the digit positions. Template matching is used as a method for digit recognition. The actual solution is computed using a backtracking algorithm. Experiments conducted on various types of sudoku questions demonstrate the efficiency and robustness of our proposed approaches in real-world scenarios. The algorithm is found to be capable of handling cases of translation, perspective, illumination gradient, scaling, and background clutter.