Correspondence Problem - Simple Correlation-based Example

Simple Correlation-based Example

A simple method is to compare small patches between rectified images. This works best with images taken at roughly the same point of view and either at the same time or with little to no movement of the scene between image captures; such as stereo images.

Using a left and right image, pass a small window over each position in the left image. For each position check how well it compares with the same location in the right image. Also compare against several locations near that, for the objects in one image may not be at exactly the same image-location in the other image. When you find the best fit the difference in image-location is the correspondence of that feature/point. It is possible that there is no fit that is good enough. This may mean the feature is not present in both images, moved farther than your search accounted for, changed enough between images that the method you use to match is not working, or are being hidden by other parts of the image.