In the following we provide details for the chosen object representation and the matching algorithm. In general, there are two possibilities for generating object related information. First, one could extract features from a 3D object model, and second, it is feasible to use two-dimensional views of an object as basis. In cognitive psychology a number of theories have been developed with regard to object representation in the human brain. From the views that can be generated from a real-world object we prefer so called canonical views.
Canonical views are views that allow humans for easier object recognition.
For a car, one possible canonical view is a slightly elevated view of the frontal and side parts of the object. A view of the bottom of a car is in general not considered canonical. The following image shows, on the left, a canonical view of a tricycle. On the right side, a non-canonical view is shown. For each object view only a few parameters are stored in the database.