Most view-based vision algorithms are based on strong assumptions about the disposition of the objects in the image. To safely apply those algorithms in real world image sequences, we are proposing that a vision system should be divided into two components. The first component contains an approximate world model of the scene --- a low accuracy, coarse description of the objects and actions in the world. Approximate world models are constructed and updated by simple vision routines and by the use of contextual information. The second component employs view-based algorithms to perform required perceptual tasks; the selection and control of the view-based methods are determined by the information provided by the approximate world model. We demonstrate the approximate world model approach in a project to control cameras in a TV studio. In our Intelligent Studio automatic cameras respond to verbal requests for shots from the TV director.