Encoding and estimation of first- and second-order binocular disparity in natural images

Paul B Hibbard,Ross Goutcher,David W Hunter

doi:10.1016/j.visres.2015.10.016

Paul B Hibbard, Ross Goutcher + Show 1 more

Open Access

https://doi.org/10.1016/j.visres.2015.10.016

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Abstract

The first stage of processing of binocular information in the visual cortex is performed by mechanisms that are bandpass-tuned for spatial frequency and orientation. Psychophysical and physiological evidence have also demonstrated the existence of second-order mechanisms in binocular processing, which can encode disparities that are not directly accessible to first-order mechanisms. We compared the responses of first- and second-order binocular filters to natural images. We found that the responses of the second-order mechanisms are to some extent correlated with the responses of the first-order mechanisms, and that they can contribute to increasing both the accuracy, and depth range, of binocular stereopsis.

Highlights

To determine whether the second-order channel can improve the accuracy of disparity estimation in natural images, we examined the distributions of disparity estimates derived from first- and second-order channels to naturalistic images, with a constant, known, disparity
We calculated the distributions of phase disparities in binocular natural images
Since the range of phase disparities is limited to ±p, this means that the range of equivalent positional disparities is inversely proportional to the spatial frequency tuning of the filters

Summary

Introduction

These disparities are encoded by binocular neurons in the visual cortex These neurons, whose responses are affected by the images formed in both eyes, are found in many cortical areas, including V1 (Barlow, Blakemore, & Pettigrew, 1967; Hubel & Livingstone, 1987; Poggio & Poggio, 1984), V2 (Bredfeldt & Cumming, 2006; Thomas, Cumming, & Parker, 2002; Zhou, Friedman, & von der Heydt, 2000), V3/V3A (Anzai, Chowdhury, & De Angelis, 2011; Cottereau, McKee, & Norcia, 2012) V4 (Shiozaki, Tanabe, Doi, & Fujita, 2012; Umeda, Tanabe, & Fujita, 2007) and V5/hMT+ (Krug & Parker, 2011). This wide spread of disparity sensitive areas across the cortex allows disparity processing to be specialised for distinct functional roles (Krug & Parker, 2011; Parker, 2007; Roe, Parker, Born, & DeAngelis, 2007).

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