The horizontal disparity direction vs. the stimulus disparity direction in the perception of the depth of two-dimensional patterns

Farell, Bart; Chai, Yu-Chin; Fernandez, Julian M.

doi:10.1167/10.4.25

Cited by 4 publications

(9 citation statements)

References 28 publications

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“…We showed that unidisparity plaids induce robust DVRs, characterized by two components: one, at very short latency, driven by the disparity of the gratings, and another, delayed by 10–15 ms, driven by the disparity in the pattern. We thus confirmed that the visual system is capable of extracting pattern disparities from plaids, as previously reported on the basis of depth perception experiments (Farell, 1998; Farell, Chai, and Fernandez, 2010; Chai and Farell, 2009; Farell, 2003). Importantly, we were able to rule out alternative interpretations, such as an effect of distortion products (Delicato and Qian, 2005).…”

Section: Discussionsupporting

confidence: 91%

Temporal Evolution of Pattern Disparity Processing in Humans

et al. 2013

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Stereo matching, i.e., the matching by the visual system of corresponding parts of the images seen by the two eyes, is inherently a 2-D problem. To gain insights into how this operation is carried out by the visual system, we measured, in human subjects, the reflexive vergence eye movements elicited by the sudden presentation of stereo plaids. We found compelling evidence that the 2-D pattern disparity is computed by combining disparities first extracted within orientation selective channels. This neural computation takes 10–15 ms, and is carried out even when subjects perceive not a single plaid but rather two gratings in different depth planes (transparency). However, we found that 1-D disparities are not always effectively combined: When spatial frequency and contrast of the gratings are sufficiently different pattern disparity is not computed, a result that cannot be simply attributed to the transparency of such stimuli. Based on our results, we propose that a narrow-band implementation of the Intersection Of Constraints (IOC) rule (Fennema and Thompson, 1979; Adelson and Movshon, 1982), preceded by cross-orientation suppression, underlies the extraction of pattern disparity.

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Section: Discussionsupporting

confidence: 91%

Temporal Evolution of Pattern Disparity Processing in Humans

et al. 2013

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“…That is, the separation of stimuli within a display, in terms either of visual angle or carrier wavelengths, might have been sub-optimal for accurate coding of disparities with strongly divergent directions. However, the perceived depth separation between plaids, whether these are laterally adjacent (Farell, Chai, & Fernandez, 2010) or separated by another stimuli (Supplement Fig. S2), is consistent with a horizontal disparity metric despite a considerable difference in two-dimensional disparity direction.…”

Section: Offset and Gainsupporting

confidence: 59%

“…Suppose the plaids had disparities with equal magnitudes and orthogonal directions, +45°and À45°. They would then have equal horizontal disparities and should appear at the same depth (Farell, Chai, & Fernandez, 2010). But if the grating (oriented at, say, 135°) had a disparity that gave it the same apparent depth as one of the plaids, it should appear at different a depth from the other plaid.…”

Section: Experiments 1 Perceived Depth Ordermentioning

confidence: 99%

“…In the case of a pair of 2-D stimuli, a different rule applies. A depth match between two plaids occurs when the horizontal components of the stimulus disparities are equal, a result holding over a considerable range of vertical carrier disparity differences (Farell, Chai, & Fernandez, 2010). In all these cases, the disparity in question was that of the grating or plaid carrier.…”

Section: Experiments 1 Perceived Depth Ordermentioning

confidence: 99%

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Perceived depth in non-transitive stereo displays

Farell

2014

Vision Research

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The separation between the eyes shapes the distribution of binocular disparities and gives a special role to horizontal disparities. However, for one-dimensional stimuli, disparity direction, like motion direction, is linked to stimulus orientation. This makes the perceived depth of one-dimensional stimuli orientation dependent and generally non-veridical. It also allows perceived depth to violate transitivity. Three stimuli, A, B, and C, can be arranged such that A > B (stimulus A is seen as farther than stimulus B when they are presented together) and B > C, yet A ⩽ C. This study examines how the visual system handles the depth of A, B, and C when they are presented together, forming a pairwise inconsistent stereo display. Observers' depth judgments of displays containing a grating and two plaids resolved transitivity violations among the component stimulus pairs. However, these judgments were inconsistent with judgments of the same stimuli within depth-consistent displays containing no transitivity violations. To understand the contribution of individual disparity signals, observers were instructed in subsequent experiments to judge the depth of a subset of display stimuli. This attentional instruction was ineffective; relevant and irrelevant stimuli contributed equally to depth judgments. Thus, the perceived depth separating a pair of stimuli depended on the disparities of the other stimuli presented concurrently. This context dependence of stereo depth can be approximated by an obligatory pooling and comparison of the disparities of one- and two-dimensional stimuli along an axis defined locally by the stimuli.

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“…In another condition, the target stimulus was 2-D, the same as the reference stimuli. In this case, we expect to find the perceptual depth match occurring when the target and reference stimuli have disparities with horizontal components that are equal, Attention in stereo depth judgments regardless of whether the disparity directions are parallel or perpendicular (Farell et al, 2010). For example, a pair of 2-D stimuli whose disparity directions are at +45° (where 0° is horizontal) should be seen as equal in depth when their disparity magnitudes are equal.…”

Section: Disparity Direction and Dimensionalitymentioning

confidence: 97%

Attentional selection in judgments of stereo depth

Farell

2019

Vision Research

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Stereoscopic depth is most useful when it comes from relative rather than absolute disparities. However, the depth perceived from relative disparities can vary with stimulus parameters that have no connection with depth or are irrelevant to the task. We investigated observers' ability to judge the stereo depth of task-relevant stimuli while ignoring irrelevant stimuli. The calculation of depth from disparity differs for 1-D and 2-D stimuli and we investigated the role this difference plays in observers' ability to selectively process relevant information. We show that the presence of irrelevant disparities affects perceived depth differently depending on stimulus dimensionality. Observers could not ignore disparities of irrelevant stimuli when they judged the relative depth between a 1-D stimulus (a grating) and a 2-D stimulus (a plaid). Yet these irrelevant disparities did not affect judgments of the relative depth between 2-D stimuli. Two processes contributing to stereo depth were identified, only one of which computes depth from a horizontal disparity metric and permits attentional selection. The other uses all stimuli, relevant and irrelevant, to calculate an effective disparity direction for comparing disparity magnitudes. These processes produce inseparable effects in most data sets. Using m u l t i p l e d i s p a r i t y d i re c t i o n s a n d comparing 1-D and 2-D stimuli can distinguish them.

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The horizontal disparity direction vs. the stimulus disparity direction in the perception of the depth of two-dimensional patterns

Cited by 4 publications

References 28 publications

Temporal Evolution of Pattern Disparity Processing in Humans

Temporal Evolution of Pattern Disparity Processing in Humans

Perceived depth in non-transitive stereo displays

Attentional selection in judgments of stereo depth

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