On active camera control and camera motion recovery with foveate wavelet transform

In this paper, a new variable resolution technique, foveate wavelet transform (FWT), is proposed to represent digital images in an effort to efficiently represent visual data. Compared to existing variable resolution techniques, the strength of the proposed scheme encompasses its linearity preservation, orientation selectivity, and flexibility while supporting interesting behaviors resembling the animate vision system. The linearity preservation of the FWT is due to the fact that only low and/or high-pass filterings are carried out in different regions of an image in the transform. The orientation selectivity indicates the fact that details along the horizontal, vertical, and diagonal directions are readily available in the FWT representation. The flexibility of this new representation technique is witnessed by the readiness of its extensions to represent foveae of different number, shape, and locations. To demonstrate the efficacy of the FWT, two applications are presented. First, an FWT-based active camera control scheme is developed, where the computer can move a camera to track the moving object in the scene. Second, an FWT-based method purporting to recover pan/tilt/zoom camera movements from video clips is developed. Experiments of these two applications have shown encouraging performances.