Appendix 3—table 1. The used six panoramic high-resolution digital images of natural scenes were downloaded from:

https://commons.wikimedia.org/wiki/File:Swampy_forest_panorama.jpg

https://commons.wikimedia.org/wiki/File:2014-08-29_11_51_08_Full_360_degree_panorama_from_the_fire_tower_on_Apple_Pie_Hill_in_Wharton_State_Forest,_Tabernacle_Township,_New_Jersey.jpg

https://en.wikipedia.org/wiki/File:Helvellyn_Striding_Edge_360_Panorama,_Lake_District_-_June_09.jpg

https://commons.wikimedia.org/wiki/File:Schleienl%C3%B6cher_Hard_360%C2%B0_Panorama.jpg https://farm3.staticflickr.com/2820/9296652749_7c502de9e7_o.jpg

http://www.bodenstab.org/panorama/images/Green%20Valley/panorama.jpg