Calif.-based manufacturer Elite Screens serves the residential and commercial markets. If you’ve ever considered using InfoComm’s Projected Image System Contrast Ratio (PISCR) standard, which aims to maximize image capabilities in ambient light, you need to be up to date on the terms below.
Elite marketing manager Dave Rodgers offers three key terms that integrators should familiarize themselves with to better understand video image quality.
ANSI Lumens
Rodgers says the American National Standards Institute (ANSI) aver-aged multiple readings of visible light from various angles to formulate a standardized unit of measure called ANSI Lumens. This measurement places a value on light intensity as a “unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of one candle intensity.”
Mathematically, it is measurement of one candela of visible light per squared radian or more simply, “a candela is about the equivalent of the light of one candle.”
Symbol: lm
Foot Lamberts
A measurement of visible light that equals 1 circular candela per square foot or 3.426 candelas per square meter.
Symbol: Lv or ftL
Image Luminance
This can be determined by multiplying the Foot Lamberts times the projection screen’s reflectivity or gain. Image luminance is the overall image bright-ness created by the combination of a projector’s output and screen reflectivity.
For example, a 1.0-gain, 100-inch 1.78:1 aspect ratio screen multiplied by 33Lv produces 33 candelas per square foot luminance, whereas a screen with half the gain (0.5) produces 16.5 candela per square foot.
Heard of PISCR? Want to read more? Here’s our take.
