Billock, Cunningham & Tsou (2008) 7 APPROVED FOR PUBLIC RELEASEvalues of B. The minimum is near ȕ=1. 6, which typifies images with less high spatial frequency content than the vast majority of natural images ( ȕ near 1. 1). This implies that discrimination between fractal camouflaged objects is somewhat more difficult when the statistics of camouflaged objects are sufficiently similar to the statistics of natural images (as any sensible camouflage scheme should be), compared to the less natural B value of 1. 6. This applies regardless of the background's ȕ value, which has implications for fratricide; friendlies and hostiles will be somewhat harder to tell apart for naturalistically camouflaged images, even when friendlies and hostiles are both visible against their backgrounds. Figure 4. Individual data from all 4 observers for all 4 conditions.