On the relationship between the spatial channels for luminance and disparity processing

Abstract

To determine the relationship between the spatial channels for luminance and shape-from-stereo-disparity processing we measured disparity modulation sensitivity as a function of disparity spatial frequency for sinusoidal modulations of a field of Gabor micropatterns of differing luminance spatial frequency. We first examine the effects of contrast, spatial bandwidth and element density and show that it is only the last of these which is critical for the shape of the disparity modulation threshold function. We show that the shape of this function depends on the luminance spatial frequency of the surface that is modulated in depth. Specifically, low corrugation frequencies enjoy a greater scale support from the early luminance spatial filters than do high corrugation frequencies. The results are consistent with higher spatial frequency disparity channels receiving a greater input from higher spatial frequency luminance channels.

Why Is Spatial Stereoresolution So Low?

“…Bradshaw and Rogers (1999) also used displays that contained only 5.7 dots/deg 2 , but they did not present these low-density stimuli at high spatial frequencies, and therefore, they did not estimate stereoresolution. Hess et al (1999) observed a clear effect of element density on stereoresolution, but the elements were Gabor patches, so their results are not directly comparable with ours. Harris et al (1997) attempted to determine the smallest spatial mechanism used in disparity estimation.…”

“…Figure 12 illustrates the relationship between spatial filtering, window size, and regional intensity variation. [Hess et al (1999) described a similar relationship between luminance frequency content and disparity modulation sensitivity.] Each of the five insets represents a monocular image captured by a correlation window.…”

A luminance-contrast-aware disparity model and applications

“…The range of disparity detection thresholds specified by our model is in good agreement with the data in [Lee and Rogers 1997] for measured mid-range disparity and luminance frequencies. For more extreme ranges, similar to [Hess et al 1999], we observe that, for low-frequency disparity corrugations, a wide range of luminance frequencies lead to good stereoacuity, while for higher-frequency disparity corrugations stereoacuity is weak for low luminance frequencies.…”

“…In this work, we significantly expand them to 0.3-20 cpd for luminance frequency, 0.05-2 cpd for disparity corrugation frequency and up to 20 arcmin for disparity magnitudes. The results by Lee et al have been challenged by Hess et al [1999], who experimented with randomlypositioned Gabor patches with modulated disparity. Hess et al found that low-frequency disparity modulations were detected equally well for low and high-luminance frequencies.…”

Analysis of disparity distortions in omnistereoscopic displays

“…The luminance signal decreases in the periphery because of factors such as poorer optics, sparser retinal sampling, and greater pooling of photoreceptors by each ganglion cell [Banks et al 1991]. Stereo performance worsens in the periphery but no worse than one would expect from the worsening input luminance signals [Hess et al 1999;Banks et al 2004]. Indeed, at sufficiently low luminance spatial frequencies (or, equivalently, low dot densities if one is using random dot stereograms) detection thresholds for disparity corrugations in the fovea are similar to those in the periphery.…”