Image Registration - Introduction

The Image Registration tool is used to bring images into alignment, for example:

When multiple scans are performed on the same subject, but the the image planes are not in the same locations on every scan (intra-subject registration). The multiple scans may be performed at different times on the same medical scanning device, or they may be collected using a different modality (e.g. MRI, CT, SPECT, PET).
When you have scans of the same type performed on different subjects (inter-subject registration). You may want to register one of your scans to an atlas, or register several scans to create an atlas.

You can choose the type and number of degrees of freedom to meet the demands of your problem. The degrees of freedom allow different types of image distortion allowed to obtain a good match.

The Image Registration tool works by calculating a "cost function" that reaches a maximum or minimum as images are brought into alignment. The alignment is adjusted iteratively until the best value of the cost function is found.

There is also a version of the Registration tool that is specifically "tuned" for time-series registration where the image to be registered are from a single subject, and where the images are already in a fairly close alignment. This situation is often encountered in functional imaging, where a series of images is collected an there is very little patient motion between the images. Use of the Time Series Registration tool allows much quicker registration of such data.

To start the Image Registration tool, select it from the Toolkits menu:

This brings up the Image Registration tool:

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