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Debi Stransky, Laurie M. Wilcox; On the quantitative nature of depth percepts from fused and diplopic stimuli. Journal of Vision 2011;11(11):338. https://doi.org/10.1167/11.11.338.
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Introduction. Psychophysical and physiological studies of stereopsis have demonstrated the existence of luminance based (1st-order) and contrast-based (2nd-order) processing. The 2nd-order mechanism is thought to provide depth information when the luminance information is unreliable or unavailable. A number of investigators have suggested that 2nd-order stereopsis provides only qualitative depth information, but this proposal has not been tested empirically. The aim of this set of experiments is to evaluate this claim and in doing so clarify the contribution of 2nd-order processing to human depth perception.
Methodology. We have used a novel two-temporal alternative forced-choice procedure and a method of constant stimuli. This task was designed to avoid the separation confound inherent in discrimination tasks using diplopic stimuli. Observers were required to judge which of two intervals contained the largest difference in depth between a reference + disparity pedestal and a target + disparity pedestal. We assessed performance across a large range of fused and diplopic disparities, and measured diplopia for each observer. In addition we used stimuli designed to favour 1st-order, or isolate 2nd-order processing, to permit comparison of the relative contributions of these two mechanisms.
Results. All observers were able to perform the 2IFC depth interval judgment using both 1st and 2nd-order stimuli, though there were large and consistent differences between these conditions. The most notable result is that observers perceived quantitative depth from targets that isolated 2nd-order processing. Results from the 1st-order condition show a clear transition from high-resolution performance in the fused range to coarser low-resolution depth perception in the diplopic range, which is likely mediated by 2nd-order processing. This study provides the first definitive evidence that quantitative depth can be provided by both 1st- and 2nd-order mechanisms in the fused range, but only the 2nd-order signal is used when stimuli are diplopic.
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Nunua makala hii kwa akaunti. Debi Stransky, Laurie M. Wilcox; Juu ya asili ya kiasi cha kina cha kina cha fused na diplopic stimuli. Journal of Vision 2011 11 11 338 (Jarida la Maono 2011) Download file: ARV (Arv) (kuchapishwa) Uchunguzi wa kisaikolojia na kisaikolojia wa stereopsis umeonyesha kuwepo kwa usindikaji wa msingi wa mwangaza (nambari ya kwanza) na msingi wa tofauti (nambari ya pili). Utaratibu wa utaratibu wa pili unafikiriwa kutoa habari ya kina wakati habari ya mwangaza haitegemei au haipatikani. Watafiti kadhaa wamedokeza kwamba stereopsis ya utaratibu wa pili hutoa habari ya kina cha ubora tu, lakini pendekezo hili halijajaribiwa empirically. Lengo la jaribio hili ni kutathmini madai haya na kwa kufanya hivyo kufafanua mchango wa usindikaji wa utaratibu wa pili kwa utambuzi wa kina wa binadamu. Mbinu. Tumetumia mbinu mpya ya kuchagua kwa kulazimishwa na mbinu ya vichocheo vya mara kwa mara. Kazi hii ilitengenezwa ili kuepuka kutenganisha confound asili katika kazi ya utambuzi kutumia diplopic stimuli. Kwa mfano, mtihani wa msingi unaonyesha tofauti kubwa kati ya msingi wa msingi wa msingi na msingi wa msingi wa msingi. Tulichunguza utendaji katika mbalimbali kubwa ya tofauti fused na diplopic, na kipimo diplopia kwa kila mtazamaji. Kwa kuongezea, tulitumia vichocheo vilivyopangwa kupendelea utaratibu wa kwanza au kutenganisha utaratibu wa pili ili kuruhusu kulinganisha michango ya jamaa ya taratibu hizi mbili. Matokeo. Watafiti wote waliweza kufanya hukumu ya 2IFC ya kina cha muda kwa kutumia kichocheo cha kwanza na cha pili, ingawa kulikuwa na tofauti kubwa na thabiti kati ya hali hizi. Matokeo ya kwanza ni kwamba watazamaji walipata kina cha kiasi kutoka kwa malengo ambayo yalijitenga na usindikaji wa utaratibu wa pili. Matokeo kutoka hali ya utaratibu wa kwanza yanaonyesha mabadiliko ya wazi kutoka kwa utendaji wa azimio la juu katika safu ya fused hadi kwa utambuzi wa kina wa azimio la chini katika safu ya diplopic, ambayo inawezekana kuendeshwa na usindikaji wa utaratibu wa pili. Utafiti huu hutoa ushahidi wa kwanza wa uhakika kwamba kina cha kiasi kinaweza kutolewa na utaratibu wa kwanza na wa pili katika safu ya fused, lakini ishara ya pili tu hutumiwa wakati stimuli ni diplopic. PDF hii inapatikana kwa wanachama tu