Use of broadcast cameras to support the Omnicam
It is impractical to obtain a tightly-zoomed high-definition close-up simply by selecting a window from the Omnicam image. For example, to obtain the same resolution as is available from an HD broadcast camera with a horizontal lens angle of 5 degrees would need the 180-degree panorama to have a horizontal resolution of about 70k pixels (36 times that of an HD image). It therefore makes sense to use conventional broadcast cameras to provide close-ups of key areas of the scene, as used in conventional coverage. To allow the user to zoom smoothly from a wide shot from the Omnicam into a region-of-interest covered by a broadcast camera, it is necessary to ensure that the images from the two cameras can be matched – both spatially and in terms of colorimetry. The figure below compares an image from an HD broadcast camera (right) to the corresponding portion of the Omnicam image (left), after background alignment and colour matching, showing the potential gain in resolution (BBC).