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

Luminance and timing control during visual presentation of natural scenes

“…In terms of future developments, this same device will be extensible to other visual presentation hardware, as well to more sensory modalities. In terms of extending VISTO to other visual presentation hardware, such as HDR monitors [24] it would be desirable to increase resolution. As resolution depends on the feedback resistance to the OpAmp, it might me increased by increasing the resistance value; however, an important limitation in this sense is given by the 8bit sampling of Arduino, which only allows for 256 levels of luminance.…”

Abrupt darkening under high dynamic range (HDR) luminance invokes facilitation for high-contrast targets and grouping by luminance similarity

“…All images were projected from a DLA-RS600U 4K Reference Projector (JVC, Kanagawa, Japan) and displayed biocularly on an HD projection screen ( Hung et al, 2019 ; Hung, Callahan-Flintoft, et al, 2020 ). Images spanned 1920 × 1080 pixels in resolution (48.7 cm × 27.3 cm, width × height) and were observed from a chin-rest-stabilized viewing distance of 78 cm, thus spanning a 34.7° × 19.9° viewing angle with pixel size 0.0181° × 0.0184°.…”

“…We used the Psychtoolbox command PsychImaging(‘AddTask’, ‘General’, ‘EnableNative11BitFramebuffer’) to disable and bypass the hardware's gamma color lookup table and switch the framebuffer into 11-bpc mode, verified by spectrophotometer (PR-745; Photo Research, Los Angeles, CA). We then applied a 75-point log-linear gamma correction, and the resulting gray levels spanned a range of 636.4 cd/m 2 ( u , v = 0.1953, 0.3199; x , y = 0.3200, 0.3494; 6037K) to 0.006055 cd/m 2 at regular log-linear steps, for a maximum contrast ratio of over 100,000-to-1 in a single image (static projector iris) ( Hung, Callahan-Flintoft, et al, 2020 ). This range spans mesopic vision (0.001–3 cd/m 2 , when both cones and rods are required to support vision) to the lower end of photopic vision (10–10 8 cd/m 2 ), consistent with seeing in mixed indoor/outdoor environments and in twilight (e.g., nighttime street, outdoor lighting, aviation lighting).…”

“…Across all blocks, the target was a contrast mixture of two Gabors at 45° (A, tilted right) and 135° (B, tilted left), presented at the central patch at a fixed mean luminance of 4 cd/m 2 , and subjects indicated via keypress the orientation of the stronger target Gabor. At full contrast (100%), the pixels of each Gabor spanned 3.3× to 0.3× its patch luminance (less than the requested range of 10× to 0.1× patch luminance, due to projector light scatter) ( Hung, Callahan-Flintoft, et al, 2020 ; Hung, Larkin, et al, 2020 ). The target was shown at one of the five possible A:B contrast mixtures of 70%:30%, 60%:40%, 50%:50%, 40%:60%, or 30%:70%.…”