The information content of panoramic images I: The rotational errors and the similarity of views in rectangular experimental arenas.

Animals relocating a target corner in a rectangular space often make rotational errors searching not only at the target corner but also at the diagonally opposite corner. The authors tested whether view-based navigation can explain rotational errors by recording panoramic snapshots at regularly spaced locations in a rectangular box. The authors calculated the global image difference between the image at each location and the image recorded at a target location in 1 of the corners, thus creating a 2-dimensional map of image differences. The authors found the most pronounced minima of image differences at the target corner and the diagonally opposite corner--conditions favoring rotational errors. The authors confirmed these results in virtual reality simulations and showed that the relative salience of different visual cues determines whether image differences are dominated by geometry or by features. The geometry of space is thus implicitly contained in panoramic images and does not require explicit computation by a dedicated module. A testable prediction is that animals making rotational errors in rectangular spaces are guided by remembered views.