1. A computer-implemented method for modeling objects within two-dimensional video data by three-dimensional models, the method comprising executing on a processor the steps of: replacing an image of an object observed within a two-dimensional image field of view of video data from a camera with a three-dimensional polygonal model that is selected from a plurality of object-type three-dimensional polygonal models that each have projected sizes and different bounding box aspect ratios, in response to the selected three-dimensional polygonal model having: a ratio of a projected size to a size of an image blob bounding box determined for the observed two-dimensional object image that meets a threshold value; and an aspect ratio that is more similar to an aspect ratio of the image blob bounding box determined for the observed two-dimensional object image, relative to aspect ratios of bounding boxes of respective ones of others of the plurality of object-type three-dimensional polygonal models.