Data processing

First data (130) comprising a first collection of coordinate data (135) representing position(s) of a first group of object(s) detected in a first frame of a scene is obtained. Second data (140) comprising a second collection of coordinate data (145) representing position(s) of a second group of object(s) detected in a second frame of the scene is obtained, the second frame representing a different view of the scene than the first (e.g. post-correction). It is determined whether any of the first group of objects correspond to any of the second group of objects in the scene based on the first and second coordinate data collections, e.g. by transforming first and/or coordinate data collections so that they correspond to a common coordinate system and determining differences according to the common system. The first and second frames are obtained from image data captured from a single camera position, e.g. using a single camera with a fish-eye lens. The first and second frames may be generated by applying transformation(s) to image data captured from the single camera position to adjust a geometric distortion of a frame presented by the image data.