scholarly journals An 11-bit High Dynamic Range (HDR) Luminance Display and Its Use to Discover Contextual Mechanisms of Real-World Luminance Normalization for Visual Acuity and Target Discrimination

2019 ◽  
Author(s):  
Chou P Hung ◽  
Chloe Callahan-Flintoft ◽  
Paul D Fedele ◽  
Kim F Fluitt ◽  
Onyekachi Odoemene ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Real World ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Automatic Target Recognition ◽  
Facilitation Effect ◽  
Software Environment ◽  
Temporal Precision ◽  
Central Target ◽  
High Dynamic

ABSTRACTLuminance can vary widely when scanning across a scene, by up to 10^9 to 1, requiring multiple normalizing mechanisms spanning from the retina to cortex to support visual acuity and recognition. Vision models based on standard dynamic range luminance contrast ratios below 100 to 1 have limited ability to generalize to real-world scenes with contrast ratios over 10,000 to 1 (high dynamic range [HDR]). Understanding and modeling brain mechanisms of HDR luminance normalization is thus important for military applications, including automatic target recognition, display tone mapping, and camouflage. Yet, computer display of HDR stimuli was until recently unavailable or impractical for research. Here we describe procedures for setup, calibration, and precision check of an HDR display system with over 100,000 to 1 luminance dynamic range (650–0.0065 cd/m^2), pseudo 11-bit grayscale precision, and 3-ms temporal precision in the MATLAB/Psychtoolbox software environment. The setup is synchronized with electroencephalography and IR eye-tracking measurements. We report measures of HDR visual acuity and the discovery of a novel phenomenon—that abrupt darkening (from 400 to 4 cd/m^2) engages contextual facilitation, distorting the perceived orientation of a high-contrast central target. Surprisingly, the facilitation effect depended on luminance similarity, contradicting both classic divisive and subtractive models of contextual normalization.

Low-contrast Acuity Under Strong Luminance Dynamics and Potential Benefits of Divisive Display Augmented Reality

2021 ◽  
Author(s):  
Chou P. Hung ◽  
Chloe Callahan-Flintoft ◽  
Paul D. Fedele ◽  
Kim F. Fluitt ◽  
Barry D. Vaughan ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Augmented Reality ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Luminance Contrast ◽  
Display System ◽  
Single Image ◽  
Low Contrast ◽  
Potential Benefits ◽  
High Dynamic

Understanding and predicting outdoor visual performance in augmented reality (AR) requires characterizing and modeling vision under strong luminance dynamics, including luminance differences of 10000-to-1 in a single image (high dynamic range, HDR). Classic models of vision, based on displays with 100-to-1 luminance contrast, have limited ability to generalize to HDR environments. An important question is whether low-contrast visibility, potentially useful for titrating saliency for AR applications, is resilient to saccade-induced strong luminance dynamics. The authors developed an HDR display system with up to 100,000-to-1 contrast and assessed how strong luminance dynamics affect low-contrast visual acuity. They show that, immediately following flashes of 25× or 100× luminance, visual acuity is unaffected at 90% letter Weber contrast and only minimally affected at lower letter contrasts (up to +0.20 LogMAR for 10% contrast). The resilience of low-contrast acuity across luminance changes opens up research on divisive display AR (ddAR) to effectively titrate salience under naturalistic HDR luminance.

scholarly journals Reconstruction of cumulative daylight illumination fields from high dynamic range imaging: Theory, deployment and in-situ validation

2020 ◽  
pp. 147715352094575
Author(s):  
J Mardaljevic ◽  
S Cannon-Brookes ◽  
N Blades ◽  
K Lithgow
Keyword(s):  
Real World ◽  
Dynamic Range ◽  
Digital Camera ◽  
High Dynamic Range ◽  
Range Image ◽  
Real World Setting ◽  
In Situ Conditions ◽  
High Dynamic ◽  
Historic Conservation

A novel high-dynamic range camera-based approach to measure the cumulative daylight dose in historic/conservation spaces has been devised and tested in a real-world setting under normal viewing conditions. The technique derives illuminance from the high-dynamic range-acquired luminance at numerous patches of the wall surfaces visible in the high-dynamic range image. These patches serve as proxy illuminance meters, thereby allowing the prevailing illumination field across the entire visible wall to be derived using a Kriging algorithm. The technique was validated under both controlled and in-situ conditions over periods of several months and shown to have comparable accuracy to the illuminance logging devices commonly used in historic/conservation settings. The set-up comprising a consumer digital camera and tethered computer proved remarkably resilient and allowed for continuous monitoring periods of six months or more. Application in a real-world setting revealed operational practicalities that would not have been found in a controlled environment.

scholarly journals A 100,000-to-1 high dynamic range (HDR) luminance display for investigating visual perception under real-world luminance dynamics

2020 ◽  
Vol 338 ◽  
pp. 108684 ◽  
Author(s):  
Chou P. Hung ◽  
Chloe Callahan-Flintoft ◽  
Anthony J. Walker ◽  
Paul D. Fedele ◽  
Kim F. Fluitt ◽  
...  
Keyword(s):  
Visual Perception ◽  
Real World ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
High Dynamic

scholarly journals Low-contrast Acuity Under Strong Luminance Dynamics and Potential Benefits of Divisive Display Augmented Reality

2020 ◽  
Author(s):  
Chou P. Hung ◽  
Chloe Callahan-Flintoft ◽  
Paul D. Fedele ◽  
Kim F. Fluitt ◽  
Barry D. Vaughan ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Augmented Reality ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Luminance Contrast ◽  
Display System ◽  
Single Image ◽  
Low Contrast ◽  
Potential Benefits ◽  
High Dynamic

Understanding and predicting outdoor visual performance in augmented reality (AR) requires characterizing and modeling vision under strong luminance dynamics, including luminance differences of 10000-to-1 in a single image (high dynamic range, HDR). Classic models of vision, based on displays with 100-to-1 luminance contrast, have limited ability to generalize to HDR environments. An important question is whether low-contrast visibility, potentially useful for titrating saliency for AR applications, is resilient to saccade-induced strong luminance dynamics. The authors developed an HDR display system with up to 100,000-to-1 contrast and assessed how strong luminance dynamics affect low-contrast visual acuity. They show that, immediately following flashes of 25× or 100× luminance, visual acuity is unaffected at 90% letter Weber contrast and only minimally affected at lower letter contrasts (up to +0.20 LogMAR for 10% contrast). The resilience of low-contrast acuity across luminance changes opens up research on divisive display AR (ddAR) to effectively titrate salience under naturalistic HDR luminance.

High-dynamic-range interferometric bragg-cell spectrum analyser

1986 ◽  
Vol 133 (1) ◽  
pp. 26
Author(s):  
J. Mellis ◽  
G.R. Adams ◽  
K.D. Ward
Keyword(s):  
Dynamic Range ◽  
High Dynamic Range ◽  
Spectrum Analyser ◽  
High Dynamic

High Dynamic Range Images and Tone Mapping Operator

2009 ◽  
Vol 35 (2) ◽  
pp. 113-122 ◽  
Author(s):  
Ke-Hu YANG ◽  
Jing JI ◽  
Jian-Jun GUO ◽  
Wen-Sheng YU
Keyword(s):  
Dynamic Range ◽  
High Dynamic Range ◽  
Tone Mapping ◽  
Range Images ◽  
High Dynamic
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