To specify control points in a pair of images you want to register, use the Control Point Selection Tool, cpselect. The tool displays the image you want to register, called the moving image, next to the image you want to compare it to, called the fixed image.
Specifying control points is a four-step process:
Start the tool, specifying the moving image and the fixed image.
Use navigation aids to explore the image, looking for visual elements that you can identify in both images. cpselect provides many ways to navigate around the image, panning and zooming to view areas of the image in more detail.
Specify matching control point pairs in the moving image and the fixed image.
Save the control points in the MATLAB® workspace.
The following figure shows the default appearance of the tool when you first start it.