Classical Computer Vision and Perspective Transformation for Sudoku Extraction

Classical computer vision techniques can be used to extract a Sudoku grid from a skewed image. The process involves a multi-step pipeline that includes grayscale conversion, Canny edge detection, dilation, and contour detection to identify the grid's four corners. A perspective transformation is then applied to warp the detected quadrilateral into a standard square view. The method also details several approaches for correctly ordering the corner points to ensure the transformation is accurate, highlighting the effectiveness of simple solutions for well-defined problems.