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Unwarping images using ArcMap: Home

This guide shows how to use ArcMap to transform an image of a curled book into a flat picture. Scanned images of books are often distorted near the binding. This process can correct that.

Welcome to the Unwarping Images using ArcMap Library Guide

When taking pictures or scans of books, there may be times that the book can’t be opened fully and the resulting image contains a curve. The georeferencing tool in ArcMap can transform and unwarp the image with relatively little effort. Other tools with image warping capabilities include Java Image Editor's warp tool http://www.jhlabs.com/ie/warp_tool.html and Photoshop's transform tool.

ArcMap's georeferencing tool is useful because it's control points give the user precise control over their adjustments to smooth a wrinkled page.

In this Library Guide we will use ArcMap to import the image, add a guiding grid, transform the image, and save it.

Before and After: Unwarping an Image in ArcMap

This scan of an early manuscript is an example of a curled and wrinkled page:   

incunable

 http://www.flickr.com/photos/nationallibrarynz_commons/5352531963/sizes/o/in/photostream/

 http://www.flickr.com/photos/nationallibrarynz_commons/5352531963/

 

After the transformation in ArcMap it is not quite as warped:

• If possible, take precise measurements of the size and spacing of the text prior to importing the image into ArcMap. It can help in placing points at the proper locations on the grid. In this example, we don’t know the actual dimensions of the text, so we will assume that the lines are evenly spaced and try to approximate the solution.

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