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January 2018

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Page 34 of 43 33 POST JANUARY 2018 OUTLOOK O OUTLOOK O OUTLOOK REFERENCE DISPLAYS C anon entered the reference display marketplace in 2013 and has since rolled out four products based on screen diagonals of 30-inch, 24-inch and a portable (or rack-mount) 17-inch. The evolving international standardization of UHD, HDR and WCG — specifically ITU-R BT.2020 on UHD/ WCG and ITU-R BT.2100 on HDR — have closely guided technical developments in these reference displays. The new 24-inch DP-V2420 reference display fully conforms to both standards. DISPLAY PANEL AND DIGITAL PROCESSING The DP-V2420 uses a 24-inch diagonal display panel having an aspect ratio of 17:9. The panel has 4096 x 2160 display pixels — 8.8 megapixels — with a pixel pitch of 132 µm. The panel can directly display 4K material — pixel for pixel — according to the 4096 (H) x 2160 (V) digital cinema standard having a 1.896:1 aspect ratio, or the alternative 4K UHD 3840 (H) x 2160 (V) with a 1.78:1 aspect ratio. The 18-bit processing engine supports a range of video manipulation capabilities. Among these is a Canon- developed algorithm for upscaling 2K/ HD video inputs — termed — for a superbly accurate portrayal devoid of any artifacts. HIGH DYNAMIC RANGE (HDR) CAPABILITIES The reference display DP-V2420 quali- fies as a Dolby Vision Mastering Monitor because it meets the HDR specifications of Dolby Vision — namely, it is capable of a peak luminance (small area spec- ulars) greater than 1000 cd/m² and a minimum luminance (black level) of 0.005 cd/m². It accepts input signals that conform to SMPTE 2084 — an EOTF is based upon the principle of perceptual quantization (PQ — originally proposed by Dolby). These input signals can be (a) transformed in post produc- tion grading from a native camera OETF to the inverse of the PQ EOTF or (b) a video source that directly originates that inverse EOTF. The display also accepts signals that conform to the Hybrid Log Gamma (HLG) system. The DP-V2420 also meets the recom- mendations for HDR outlined in the ITU-R BT.2100 standard. An important advantage of the display panel technol- ogy is the ability to portray large screen areas of white without any diminution of brightness — the panel is APL inde- pendent up to a level of 600 cd/m². Accordingly, brightness can be assessed as an absolute value. MANAGEMENT OF WIDE RANGES OF HDR The DP-V2420 incorporates many in- novative operational tools that assist in careful management of HDR imagery in postproduction, as well as on-set setup of HDR imagery and associated on-set grad- ing. A simple and intuitive menu system supports selection and setup. When dealing with input signals that might have dynamic range levels beyond the 1000 cd/m² peak luminance capability of the display a linear range setting high-bit depth process can be applied to the sig- nal (by using the display menu settings) to implement one of two modes of such processing built into the display: Clip Mode: If a given scene contains a range of escalating highlight levels, a creative decision might be made to elim- inate the highest of these and instead display selected highlights up to approxi- mately 100 percent of reference white. In such a case, the display is set to the Clip Mode — which will pass all highlights up to 100 percent level and clip all signals that are above this level. Compression Mode: If input high- light levels above that 1000 percent level — up to the 10,000 maximum — are to be faithfully displayed, then the Compression Mode is selected. This linearly compresses the input signal to ensure that its maximum highlight level matches the 1000 percent level of the display — ensuring accurate grading of the highlight regions. HDR FALSE COLOR METERING This visual tool allows different colors to be superimposed on regions of a given scene dependent upon their brightness — see Figure 1 — which shows the colors associated with the 10-bit driver for the DP-V24120 display panel. In addition, there is scale selection in the built-in waveform monitor that can automatically adjust scaling according to the particular OETF of the input signal. In the Multi-View mode, a split-screen display portrays the HDR image on the left and an SDR derivation on the right facilitating side by side comparisons during a grading process. WIDE COLOR GAMUT (WCG) CAPABILITIES The DP-2420 display panel has a native color gamut capability that conforms to the DCI-P3 specification. Although the ITU-R BT.2020 color gamut is wider than that of this display panel, gam- ut-mapping technology is used to optimize the display of color data outside the native capability of the display panel. In the new era of wide color gamut origination, interest is growing in the use of Constant Luminance (CL) systems. This was recognized in the standardization of ITU-R BT.2020 wide color gamut system by including both NCL and CL nonlinear transfer functions in that standard. Accordingly, the DP-V2410 supports Constant Luminance as well as Non-Constant Luminance (the method of color matrix conversion differs between constant and non-con- stant luminance). AN HDR/WCG 4K/2K MASTERING DISPLAY FOR HIGH-END POST PRODUCTION BY LARRY THORPE SENIOR FELLOW IMAGING TECHNOLOGIES & COMMUNICATIONS GROUP PROFESSIONAL ENGINEERING & SOLUTIONS DIVISION CANON USA MELVILLE, NY USA.CANON.COM

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