Contour Extraction from Images Using Boundary Tracing Method

This implementation performs image contour extraction using the boundary tracing method, where the function returns a positional index matrix containing the coordinates of boundary points. The boundary tracing algorithm is a fundamental image processing technique that detects object contours by analyzing grayscale value transitions within the image. The algorithm operates by systematically tracing pixel boundaries based on intensity gradients, typically implementing neighborhood search patterns (such as 8-connectivity or 4-connectivity) to identify contiguous boundary points. Through this boundary tracing approach, we obtain a matrix of positional indices representing points along the object's contour, which serves as crucial input for subsequent image analysis and recognition tasks. The implementation involves creating specialized function files that handle edge detection initialization, tracing direction management, and termination condition checks. The function's output structure organizes boundary coordinates in a matrix format [x1 y1; x2 y2; ...], enabling direct utilization in downstream image processing operations for precise contour localization. By employing boundary tracing for contour extraction, we gain enhanced understanding of object shapes and structural characteristics within images, providing robust support for advanced image processing and analytical applications. The algorithm typically includes steps like starting point detection, clockwise/counter-clockwise neighborhood searching, and boundary following until closure, ensuring complete contour extraction.