Influence of background size, luminance and eccentricity on different adaptation mechanisms

Abstract

Mechanisms of light adaptation have been traditionally explained with reference to psychophysical experimentation. However, the neural substrata involved in those mechanisms remain to be elucidated. Our study analyzed links between psychophysical measurements and retinal physiological evidence with consideration for the phenomena of rod-cone interactions, photon noise, and spatial summation. Threshold test luminances were obtained with steady background fields at mesopic and photopic light levels (i.e., 0.06–110 cd/m2) for retinal eccentricities from 0° to 15° using three combinations of background/test field sizes (i.e., 10°/2°, 10°/0.45°, and 1°/0.45°). A two-channel Maxwellian view optical system was employed to eliminate pupil effects on the measured thresholds. A model based on visual mechanisms that were described in the literature was optimized to fit the measured luminance thresholds in all experimental conditions. Our results can be described by a combination of visual mechanisms. We determined how spatial summation changed with eccentricity and how subtractive adaptation changed with eccentricity and background field size. According to our model, photon noise plays a significant role to explain contrast detection thresholds measured with the 1/0.45° background/test size combination at mesopic luminances and at off-axis eccentricities. In these conditions, our data reflect the presence of rod-cone interaction for eccentricities between 6° and 9° and luminances between 0.6 and 5 cd/m2. In spite of the increasing noise effects with eccentricity, results also show that the visual system tends to maintain a constant signal-to-noise ratio in the off-axis detection task over the whole mesopic range.

Effects of absolute luminance and luminance contrast on visual discrimination in low mesopic environments

“…Decline in some of these processes can be attenuated by increased stimulus size, but this effect does not hold true for all. When considering the low mesopic spectrum, luminance perception also varies with increasing stimulus eccentricity (Blackwell 1946, and may also be test size-dependent (Gloriani et al, 2016); however, in some instances perceptual abilities can sharpen at increasingly eccentric targets due to long wavelength preferences of the rods (Wald, 1945;Anstis, 2002). Such effects are attributed to the functional Purkinje shift as the rod density is minimal around the fovea and increases towards the periphery of the retina.…”

A Perceptually Coherent TMO for Visualization of 360$$^\circ $$ HDR Images on HMD

“…That why we need a complex perception model that takes into account the background luminance as a function. The influence of the background size and complex enlightening environment has been studied in [7,11]. Some adjustments have been proposed by Lee and Kyu-Ik [11] to express the adaptation degree F depending on the background luminance L b instead of the three original viewing conditions (Dark, Dim, Avg):…”

Tutorial: Theoretical Considerations When Planning Research on Human Factors in Lighting

“…We humans can process light information over an enormous range of ambient light levels, stretching from conditions in starlight to those in bright sunlight-that is, more than eight orders of magnitude-but the visual system does need to adapt to this. It does so through various adaptation mechanisms (only one of which is the transition from rod to cone vision described above) at the level of the pupil, the retina, and the cortex (Hood and Finkelstein 1986; for a more complete model of light adaptation, see Gloriani et al 2016). In addition, the contrast resulting from characteristics of the visual stimulus, its background, and lighting conditions needs to be sufficient.…”