Binocular disparity signals are highly informative about the three-dimensional structure of visual scenes, including aiding the detection of depth discontinuities between surfaces. Here, we examine factors affecting sensitivity to such surface discontinuities. Participants were presented with random dot stereograms depicting two planar surfaces slanted in opposite directions and were asked to judge the sign of the depth discontinuity created where those surfaces met. Although the judgement was focussed on the adjacent edges, the precision of depth discontinuity discrimination depended upon the slant of the two surfaces: increasing surface slants to ±60° increased discontinuity discrimination thresholds by, on average, a factor of 5. Control experiments examining discontinuity discrimination across surfaces with identical slants showed either biases in discontinuity judgements or reduced threshold elevation. These results suggest that sensitivity to depth discontinuities is affected by processing limitations in both local absolute disparity measurement mechanisms and mechanisms selective for disparity differences. As further evidence in support of this conclusion, we show that our results are well-described by a model of discontinuity discrimination based on the encoding of local differences in relative disparity.

双目视差信号对视觉场景的三维结构提供了丰富的信息，包括帮助检测表面之间的深度不连续性。在这里，我们检查影响对这种表面不连续性的敏感性的因素。向参与者展示了随机点立体图，描绘了两个向相反方向倾斜的平面，并被要求判断这些表面相遇处产生的深度不连续性的符号。尽管判断集中在相邻边缘，但深度不连续性辨别的精度取决于两个表面的倾斜度：将表面倾斜度增加到 ±60°，不连续性辨别阈值平均增加了 5 倍。检查具有相同倾斜度的表面上的不连续性辨别的对照实验显示不连续性判断的偏差或降低的阈值升高。这些结果表明，对深度不连续性的敏感性受到局部绝对视差测量机制和视差差异选择性机制的处理限制的影响。作为支持这一结论的进一步证据，我们表明，我们的结果可以通过基于相对差异的局部差异编码的不连续判别模型得到很好的描述。这些结果表明，对深度不连续性的敏感性受到局部绝对视差测量机制和视差差异选择性机制的处理限制的影响。作为支持这一结论的进一步证据，我们表明，我们的结果可以通过基于相对差异的局部差异编码的不连续判别模型得到很好的描述。这些结果表明，对深度不连续性的敏感性受到局部绝对视差测量机制和视差差异选择性机制的处理限制的影响。作为支持这一结论的进一步证据，我们表明，我们的结果可以通过基于相对差异的局部差异编码的不连续判别模型得到很好的描述。