A valve actuator includes an actuator housing, a piston, a linkage assembly, a magnet, and a Hall sensor. The first lever assembly has a first lever and a first bending member, and the second lever assembly has a second lever that is configured for pivotal motion relative to the first lever. A contaminated or \u201chot\u201d chamber interfaces with one or more uncontaminated imaging suites or \u201ccold\u201d chambers. The view point calculation unit is configured to calculate a view point of a user observing the scene through the display unit. The invention is also directed to an aqueous coating composition having at least 65 percent by volume of pigment, on a dry solids volume basis and an amount effective to produce good scrub resistance of up to 25 percent by weight of the vinyl acetate-ethylene binder.