Black Level Visibility as a Function of Ambient Illumination

摘要

One of the key new attributes of high-dynamic-range (HDR) imaging and displays is the ability to present many stops of shadow detail and, with the best systems, a perceptually pure black. Displays perform at their best in a dark room as no ambient illumination impinges on the surface of the display, which can elevate the display’s perceived black level. In addition, the viewer can see the most shadow detail when the region surrounding the display is also dark. In addition to applications where a display is viewed in a dark-surround environment, there are also viewing conditions where higher ambient light levels occur. Knowledgeable viewers prevent ambient illumination reflecting from the display, but even then, surrounding luminance will be increased. To understand the impact of this surrounding ambient illumination on black level visibility and shadow detail, and to further guide ambient compensation algorithms, we performed a psychophysical study to assess the human visual system’s ability to perceive detail when impacted by surround luminance. For the stimuli, we used a Gabor signal to probe the visual system’s best capability. For the display, we used a Pulsar HDR display with a large neutral density filter placed over the display to enable black levels as low 0.0006 cd/m