Registration Marks

When forms are scanned, perturbations or transformations such as rotation, zooming, reduction, and translation (shifting in position) are added to the image. These effects make it difficult to identify the different parts of the form, complicating the detection and recognition phases.

Registration marks can be used to help identify and localize the different parts of the form, so that scale, offset, and orientation of each scanned image is maintained. Registration marks are predefined shapes that are added to the original form in specific locations. These marks can then be used to identify the transformations or deformation added to the original form, and then to correct a scanned form’s orientation and resize it to its original size.

More:

Registration Mark Function Groups, Examples, and Tutorials