Interactive Mouse-Based Contour Editing and Selection for Target Objects

Implementing mouse-based contour editing and selection functionality in MATLAB has broad applications in medical image analysis, computer vision, and graphic editing domains. The core of this functionality lies in integrating MATLAB's Graphical User Interface (GUI) with the Image Processing Toolbox, enabling users to perform contour selection and adjustments through mouse interactions.

The implementation approach primarily consists of the following steps:

Image Display Initialization First load the target image and display it in a figure window. Use the `imshow` function to present the image, ensuring users can clearly visualize the contour regions requiring processing. The function handles image scaling and display optimization automatically.

Interactive Contour Selection Utilize MATLAB's `ginput` or `drawfreehand` functions for contour selection. The `ginput` function allows users to select key points through mouse clicks, returning coordinate pairs for point-based contour definition. Meanwhile, `drawfreehand` provides freehand drawing capabilities suitable for complex contour selection. Additional functions like `impoly` or `imfreehand` offer more flexible contour drawing methods with built-in constraint options.

Contour Editing and Adjustment After initial selection, users may need fine-tuning of contours. Implement draggable control points or nodes allowing free movement of contour edges. MATLAB's `setPosition` method or similar functions enable dynamic shape updates through callback functions that monitor position changes in real-time.

Data Storage and Output Upon completing edits, save the contour coordinate data for subsequent processing. The `getPosition` method extracts coordinate matrices from contour objects. Simultaneously, highlight selected contours on the image using `plot` or `drawpolygon` functions to enhance visual feedback.

User Experience Optimization Improve interaction flexibility and practicality by incorporating undo/redo functionality using stack-based data structures. Provide multiple selection tools (rectangle, polygon, freeform curves) through conditional statements that switch between different MATLAB ROI (Region of Interest) objects based on user selection.

This interactive contour editing methodology not only enhances image analysis precision but also finds extensive applications in educational demonstrations and preliminary annotation tasks for automated processing pipelines.