Model Registration and Validation

An important application of machine vision is to provide a means to monitor a scene over a period of time and report changes in the content of the scene. We have developed a validation mechanism that implements the first step towards a system for detecting changes in images of aerial scenes. Validation seeks to confirm of the presence of model objects in the image. Our system uses a 3-D site model of the scene as a basis for model validation, and eventually for detecting changes and to update the site model. The validation process is implemented in three steps: resection, fine registration of the image to the model by matching of model features to image features, and validation of the objects in the model. Our system, if necessary, is aided by shadows to help validate the model. The system has been tested using a hand-generated site model and several images of a 500:1 scale model of the site, acquired form several viewpoints.