Table 1. List of pixel attributes [17]

	Sampling location	Attribute	Threshold
Image space	Pixel center	Color reference	τcol
Object space	Primary ray hit point	Object ID	τpoid
		Surface normal	τpsn
		Shadow count	τpsc
		Texture existence	τpte
	Secondary ray hit point	Object ID	τsoid
		Surface normal	τssn
		Shadow count	τssc
		Texture existence	τste