The Future’s So Bright, I Gotta Wear Shades: Test Patterns for HDR

摘要

High dynamic range (HDR) and wide color gamut (WCG) technology present challenges to the design of a test pattern for the visual verification of systems. The previous International Telecommunications Union (ITU-R) Recommendation BT.709 paradigm defined a “zero-to-one-hundred-percent” scale, and the entire system and any reasonable display could be expected to show the full range of code values. However, SMPTE ST 2084 defines an absolute correspondence from code values up to 10,000 nits (A nit is a unit used to measure brightness and is equivalent to a candela per square meter), and even professional monitors will clip at some lower brightness level unique to their particular design. Furthermore, the ITU-R BT.2020 color gamut “container” exceeds the gamut of any professional monitor, so colors that are outside of a monitor’s particular gamut capability will be modified by the monitor. This lack of dependable behavior of monitors at the extremes of color and brightness creates additional challenges for the design of visual test patterns.