54.2: A High Dynamic Range Display Using Low and High Resolution Modulators

Abstract

We have developed an emissive high dynamic range (HDR) display that is capable of displaying a luminance range of 10,000cd/m2 to 0.1cd/m2 while maintaining all features found in conventional LCD displays such as resolution, refresh rate and image quality. We achieve that dynamic range by combining two display systems — a high resolution transmissive LCD and a low resolution, monochrome display composed of high brightness light emitting diodes (LED). This paper provides a description of the technology as well as findings from a supporting psychological study that establishes that correction for the low resolution display through compensation in the high resolution display yields an image which does not differ perceptibly from that of a purely high resolution HDR display.

A model of perceived dynamic range for HDR images

“…In a second study, the same threshold (90% preference level) was been reported for three groups of participants with the following values: 4,677 cd/m 2 for technical, 3,090 cd/m 2 for arts and 1,995 cd/m 2 for naive participants [34]. Both experiments were conducted on a dual modulation HDR display system [35], with the ability to reproduce luminance levels in the range from 0.004 to 20,000 cd/m 2 . Seven images were evaluated, six of which were real-world structured stimuli, using 34 participants.…”

Photometric image processing for high dynamic range displays

“…Relative (and even absolute) luminances are maintained, and edges will be reproduced exactly when they are below the maximum contrast of the front display of about 250 : 1 in the current production model. Only when this range is exceeded is some fidelity lost near high contrast boundaries, but this effect is well below the detectable threshold, and has not been visible in any experiments [65].…”

“…From the psychophysical theory presented in Section 2.1.1 we can establish the largest size of a rear image pixel. A second version [11,71] of the HDR display uses light emitting diodes (LED) at the largest possible size allowed by the veiling luminance effect that has been validated previously through experimental tests [65]. For a full white box occupying the center third of the screen, the maximum luminance 3 Display manufacturers often employ various methods of distorting the calculation of dynamic range, such as altering room illumination between measurements.…”

“…Most relevant to this thesis, high dynamic range display systems have been developed to accurately reproduce a much wider range of luminances. The work done by Ward [77] and Seetzen et al [64,65] has provided devices that vastly exceed the dynamic range of conventional displays.…”

HDR video past, present and future: A perspective

“…The colour wheel was removed and the greyscale video was projected through an array of lenses onto the back of a 15" XGA colour Sharp LQ150X1DG0 LCD display. The system was capable of displaying HDR images with a dynamic range of more than 75,000 : 1 [34]. els.…”