Image Processing Toolbox User's Guide Previous page   Next Page

Registering an Image

Image registration is the process of aligning two or more images of the same scene. Typically, one image, called the base image or reference image, is considered the reference to which the other images, called input images, are compared. The object of image registration is to bring the input image into alignment with the base image by applying a spatial transformation to the input image. The differences between the input image and the output image might have occurred as a result of terrain relief and other changes in perspective when imaging the same scene from different viewpoints. Lens and other internal sensor distortions, or differences between sensors and sensor types, can also cause distortion.

A spatial transformation maps locations in one image to new locations in another image. (For more details, see Spatial Transformations.) Determining the parameters of the spatial transformation needed to bring the images into alignment is key to the image registration process.

Image registration is often used as a preliminary step in other image processing applications. For example, you can use image registration to align satellite images of the earth's surface or images created by different medical diagnostic modalities (MRI and SPECT). After registration, you can compare features in the images to see how a river has migrated, how an area is flooded, or to see if a tumor is visible in an MRI or SPECT image.

Previous page  Image Registration Point Mapping Next page

© 1994-2005 The MathWorks, Inc.