Resampling is a process that involves the extraction and interpolation of gray levels from pixel locations in the original distorted image and their relocation to the approximate matrix coordinate location in the rectified (corrected) image. These are several methods for interpolating gray levels that can be applied, which include Nearest Neighbor, Bilinear Interpolation and Cubic Convolution. The more sophisticated of these methods of re-sampling takes a weighted average of the gray levels of pixels in the uncorrected image which immediately surround a particular pixel space in the corrected matrix. There are several methods of gray-level interpolation which include:

• Nearest Neighbor - uses the value of the closet pixel

• Bilinear Interpolation - uses the for nearest pixel values;

• Cubic convolution - uses the sixteen nearest pixel values.
  

Figure Identification of Grey level(s) associated with a particular cover corrected pixel location