Accurate efficient mosaicking for Wide Area Aerial Surveillance

Wide Area Aerial Surveillance (WAAS) imagery is captured by an array of smaller sensors sharing an optical center, instead of one large sensor. It is desirable to generate a single image (mosaic) from the sensor array, since it simplifies higher level vision tasks. It is important that the mosaic be of high quality, without noticeable seams, and be estimated efficiently for every frame of the video. We propose a piecewise affine model to handle image distortions not captured by a homography. This model has more degrees of freedom than a standard lens distortion model used in previous work, yet can be estimated just as efficiently by carefully selecting a small number of constraints in the optimization of model parameters. We have evaluated our algorithm on publicly available WAAS imagery and the results show our proposed model produces more accurate mosaics than the widely used lens distortion model, thus simplifying further stages of image analysis.