Lab 6: Geometric Correction
Introduction The goal of this lab is to familiarize students with an image pre-processing technique known as as geometric correction. Students are able to exercise this skill using two different types of rectification pre-processing: image-to-map and image-to-image rectification. Methods For both sections, students use the Control Points tool under the Multispectral toolset to begin the geometric correction process. Using a Polynomial Geometric Model, Erdas users have the option to choose the number of polynomials they wish to model in their rectification transformation. The number of polynomials required for use may vary based on the extent of the distortion between the original and referenced image. In Part One , the distortion that exists between the original image and the referenced map is minimal. Students use a 1st order polynomial equation to rectify the desired image. A 1st order polynomial equation requires a minimum of three Ground Control Points (GCPs) betw...