Study On Effect Factors And Mechanism Of Monocular Regions In Stereopsis

Stereopsis is an advanced perception function to identify the object depth and 3-dimentional structure obtained on the basis of binocular fusion.In recent decades,it has been one of the most popular scientific subjects in the field of binocular vision.In order to reconstruct the 3-dimensional information in the scene,the studies on stereopsis aimed at revealing the mechanisms and relevant issues in the process of binocular fusion.In the process of 3-dimensional reconstruction,the stereo matching is the most important and difficult step.Moreover,it is also the core problem in stereopsis.In the natural scene,the sight is blocked by the opaque object in the front.In this situation,some regions in the back can only be seen by one eye,which is called monocular regions.Different from the binocular regions,the object in monocular regions can not find the matching objects in binocular retinal images.Therefore,it is difficult to estimate the object depth according to the traditional disparity theory,which brings a big challenge to the stereo matching mechanism.In monocular regions,Panum's limiting case generally refers to the phenomenon that a distant object is completely blocked by an opaque object for one eye,while the other eye can see the two objects.Panum's limiting case is a simple and representative configuration,so it can be the basis and breakthrough for the study on the origin of depth in monocular regions.In Panum's limiting case,whether the perceived depth of the object originates from double fusion or single fusion is an important topic,which has been widely debated in the field of stereopsis for a long time.Researchers always focus more on the matching mechanisms in the two fusion modes and the effect factors related to the stereopsis process.This study focuses on the above controversy and current unsolved issues.We confirmed that the depth perception derived from the double fusion in Panum's limiting case,and then investigated the matching mechanisms of double fusion.On this basis,we further identified the effect factors for the double fusion and relevant mechanisms,which included the neural mechanism and the matching mechanism.This study mainly includes the following three research objectives.The first research involves the matching mechanism issues related to the two fusion modes by using a triangle type of Panum's stimuli in the four experiments.In the experiment,using a fixed view point and quick stimulation representation,we confirmed that the depth perception derived from the double fusion in Panum's limiting case.On this basis,we further proved that the matching mechanisms of double fusion is rapid alternating match other than traditional simultaneous match.This reveals the essential difference and association between double fusion and single fusion about matching mechanism,providing a new theoretical basis to set up a more optimized stereo matching algorithm.With the factors that impact the depth perception and cause the double fusion,the second research used the reaction time and duration of double fusion as dependent variables.We systematically investigated how vertical disparity gradient,cue conflict,and perceptual learning impact the double fusion,and the inherent associations therein.The research results showed the main effects of these three factors are significant.With the continuous improvement in both the vertical disparity gradient and cue conflict level and the gradual increase of perceptual learning,the reaction time of double fusion is gradually shortened and the duration is gradually lengthened.It indicates that the three factors,besides disparity,all have great effects on the depth perception of the participants in Panum's limiting case.The third study focused on the neural mechanism of the other two important factors(vertical disparity gradient and cue conflict)and investigated the effects of the two factors on the ERP components and spatial complexity of EEG signals in the depth perception process for Panum's limiting case.Firstly,the event-related potentials(EPRs)technology was used to identify the time course of the vertical disparity gradients and cue conflicts when the participants processed the Panum's limiting case.The research results showed that during the 500 ms after applying stimulation,the vertical disparity gradient was only related to early N170 components,but the cue conflict was related to both early N170 components and later N270 components.This suggests that the brain processed these two factors differently.Based on the above research,we also used the Omega complexity as an indicator,which can reflect overall connectivity conditions among brain areas,to identify the space complexity when neural signals emerge in the occipital area and frontal area,and relevant lateralization effect in left and right occipital areas.The research results showed that Omega complexity in EEG signals could reflect the neural activities induced by different levels of vertical disparity gradients and cue conflicts,and it had a strong relation with ERP components.In conclusion,this study takes the Panum's limiting case as an example,beginning with the matching mechanism of double fusion and single fusion as the breakthrough point,focusing on significant factors that may impact double fusion and its neural mechanisms,and further promoting the research step by step.This research presents innovation on experimental methods and conclusion.It improves the theoretical basis to research how stereo vision is formed in the monocular regions and provides scientific evidences to set up the perfect binocular vision computing model in computer vision and other fields.