About: http://webisa.webdatacommons.org/110265189

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	The mask can simply cover the periphery beyond the desired shape or it can be comprised of a pattern of dots or checkerboard or other shapes of alternating opaque and transparent portions.
http://www.w3.org/ns/prov#wasQuotedFrom	freepatentsonline.com