Vishwanath Dhanraj
School of Psychology, University of St Andrews, Fife KY16 9JP, UK; e-mail:
Iperception. 2012;3(8):541-6. doi: 10.1068/i0544ic. Epub 2012 Aug 22.
The question of whether defocus blur is a quantitative cue for depth perception is a topic of renewed interest. A recent study suggests that relative defocus blur can be used in computing depth throughout the visual field, particularly in regions where disparity loses precision. However, elements of the study's experimental design and theoretical analysis appear to undermine this claim. First, the study did not provide evidence that blur can be used as a quantitative depth cue. It only measured blur discrimination thresholds, not perceived depth from for blur. Second, the study's conceptualization of the complementary use of blur and disparity, and related conjectures, are based on the specific viewing geometry and fixation distance tested. They do not appear to generalize to natural viewing situations and tasks. I suggest a different way in which defocus blur might affect depth perception. Because depth-of-focus blur is a cue to egocentric distance, it could contribute to quantitative depth perception by scaling depth relations specified by other relative depth cues.
散焦模糊是否是深度感知的定量线索这一问题再次引发了人们的兴趣。最近一项研究表明，相对散焦模糊可用于计算整个视野中的深度，尤其是在视差失去精度的区域。然而，该研究的实验设计和理论分析要素似乎削弱了这一观点。首先，该研究没有提供模糊可作为定量深度线索的证据。它只测量了模糊辨别阈值，而非基于模糊的感知深度。其次，该研究对模糊与视差互补使用的概念化以及相关推测，是基于所测试的特定观察几何结构和注视距离。它们似乎无法推广到自然观察情境和任务中。我提出了一种散焦模糊可能影响深度感知的不同方式。由于焦深模糊是自我中心距离的线索，它可以通过缩放由其他相对深度线索指定的深度关系来促进定量深度感知。
