Real World Multicore Embedded Systems

Book Preface

The fundamental step for combining three-dimensional (3D) geometric data is registration, which is the process of aligning two or more images that capture the geometric structure of the same scene, but in their own relative coordinate frames, into a common coordinate frame. The images themselves can be obtained at different times and from different viewpoints, using similar or different imaging modalities. Here, we focus on volumetric registration, where the images are pixel or voxel intensities arranged in a regular grid, and the relative alignment of multiple images must be found. Volumetric registration is often used in biomedical imaging, e.g., to track changes in a patient’s anatomy using images taken at different time points or to align stacks of microscopy data in either space or time.

A registration is called rigid if the motion or change is limited to global rotations and translations, and is called deformable if it includes complex local variations. One of the images is often called the static or reference image and the second image is the moving image, and registration involves spatially transforming the moving image to align with the reference image. When registering medical images, e.g., of a patient’s anatomy taken at different time points, one must account for deformation of the anatomy itself due to the patient’s breathing, anatomical changes, and so on.