Cropping Regions of Interest in MATLAB

In MATLAB, users can easily crop regions of interest from images through interactive operations. By simply clicking two points to define a rectangle, the program automatically extracts the specified area. Below is the fundamental implementation approach with code-related details:

Display Image: Use the `imshow` function to load and display the target image, enabling users to visually select regions of interest. This function supports various image formats and adjusts display properties for optimal visualization. Interactive Point Selection: Employ the `ginput` function to capture two coordinate points clicked by the user on the image. These points represent the top-left and bottom-right corners of the rectangle. The function returns pixel coordinates stored as a vector [x1, y1; x2, y2]. Calculate Crop Area: Compute the rectangle's width and height from the selected coordinates using basic arithmetic operations (e.g., width = x2 - x1). Ensure coordinate validation to handle inverted selections. Execute Cropping: Extract the rectangular region using matrix indexing (e.g., cropped_image = original_image(y1:y2, x1:x2, :)) or the built-in `imcrop` function, which directly returns the cropped sub-image while preserving color channels for RGB images.

This method is efficient and ideal for rapid extraction of image subregions in applications like object detection or image preprocessing. The interactive mouse-driven approach eliminates manual coordinate entry, enhancing usability and workflow efficiency.