Rubbersheet

Rubbersheet refers to a conceptual and computational technique used in computer graphics and image processing. It is employed to deform an image or a set of points by treating them as if they were made of a flexible, elastic material. This deformation is achieved by defining a transformation that maps points from their original positions to new, distorted positions.

The core idea behind rubbersheeting is to create a smooth, continuous warping effect. This is often accomplished by specifying a limited number of control points. When the user moves these control points, the rest of the image or point set is warped proportionally, simulating the behavior of stretching or compressing a rubber sheet. The algorithm calculates the intermediate positions of all other points based on their proximity to the control points and the defined interpolation method.

Common applications of rubbersheeting include image retouching, animation, and spatial data manipulation. For instance, in photo editing software, rubbersheeting can be used to subtly adjust facial features, correct perspective distortions, or warp an object to fit into a new background. In scientific visualization, it can be used to align or morph different datasets. The underlying mathematical principles often involve interpolation techniques such as thin-plate splines or radial basis functions, which ensure a smooth and predictable deformation across the entire domain. The visual outcome is a distorted version of the original that appears to have been physically stretched or molded.