MATLAB Implementation of Elastic Image Registration Using B-Splines

This MATLAB program implements elastic image registration using B-spline algorithms, enabling users to perform accurate image alignment through deformable transformations in the MATLAB environment. The core algorithm employs B-spline interpolation to control image deformation via adjustable control points, optimizing the spatial correspondence between images. Image registration represents a crucial step in image processing that aligns multiple images to achieve perfect spatial overlap, facilitating subsequent analysis and processing operations. The implemented B-spline method serves as a powerful interpolation technique where control points govern the deformation grid, allowing for smooth and precise shape adjustments. The MATLAB implementation features key functions including control point initialization, B-spline coefficient computation, deformation field generation, and similarity metric optimization (typically using mutual information or sum of squared differences). Users can customize parameters such as control point spacing, regularization terms, and optimization iterations to balance registration accuracy and computational efficiency. Beyond medical image registration applications, this program extends to geographic information systems (GIS), computer vision, and remote sensing domains. The code architecture supports both 2D and 3D image registration with modular design for easy integration of different similarity metrics and optimization methods. Through this implementation, users can achieve rapid and accurate image alignment, significantly enhancing workflow efficiency while obtaining superior registration results compared to rigid transformation methods. The program includes visualization tools for monitoring registration progress and evaluating results through difference images and overlay displays. Optional multiresolution registration strategies are incorporated to handle large deformations while maintaining computational stability.