scholarly journals Occlusion and the solution to visual motion ambiguity: Looking beyond the aperture problem

10.1167/8.2.4 ◽  
2008 ◽  
Vol 8 (2) ◽  
pp. 4 ◽  
Author(s):  
Maarten J. van der Smagt ◽  
Gene R. Stoner
Keyword(s):  
Visual Motion ◽  
Aperture Problem

Aging and the Visual Perception of Motion Direction: Solving the Aperture Problem

Perception ◽  
2018 ◽  
Vol 47 (7) ◽  
pp. 735-750 ◽  
Author(s):  
Lindsey M. Shain ◽  
J. Farley Norman
Keyword(s):  
Visual Motion ◽  
Motion Direction ◽  
Line Segments ◽  
Aperture Problem ◽  
Motion Signal ◽  
True Motion ◽  
Pattern Motion ◽  
Accurate Performance ◽  
Moving Line ◽  
True Direction

An experiment required younger and older adults to estimate coherent visual motion direction from multiple motion signals, where each motion signal was locally ambiguous with respect to the true direction of pattern motion. Thus, accurate performance required the successful integration of motion signals across space (i.e., accurate performance required solution of the aperture problem) . The observers viewed arrays of either 64 or 9 moving line segments; because these lines moved behind apertures, their individual local motions were ambiguous with respect to direction (i.e., were subject to the aperture problem). Following 2.4 seconds of pattern motion on each trial (true motion directions ranged over the entire range of 360° in the fronto-parallel plane), the observers estimated the coherent direction of motion. There was an effect of direction, such that cardinal directions of pattern motion were judged with less error than oblique directions. In addition, a large effect of aging occurred—The average absolute errors of the older observers were 46% and 30.4% higher in magnitude than those exhibited by the younger observers for the 64 and 9 aperture conditions, respectively. Finally, the observers’ precision markedly deteriorated as the number of apertures was reduced from 64 to 9.

Disambiguating Visual Motion Through Contextual Feedback Modulation

2004 ◽  
Vol 16 (10) ◽  
pp. 2041-2066 ◽  
Author(s):  
Pierre Bayerl ◽  
Heiko Neumann
Keyword(s):  
Time Course ◽  
Visual Motion ◽  
Activity Patterns ◽  
Image Features ◽  
Natural Image ◽  
Local Motion ◽  
Physiological Mechanisms ◽  
Feedback Processing ◽  
Aperture Problem ◽  
Gating Mechanism

Motion of an extended boundary can be measured locally by neurons only orthogonal to its orientation (aperture problem) while this ambiguity is resolved for localized image features, such as corners or nonocclusion junctions. The integration of local motion signals sampled along the outline of a moving form reveals the object velocity. We propose a new model of V1-MT feedforward and feedback processing in which localized V1 motion signals are integrated along the feedforward path by model MT cells. Top-down feedback from MT cells in turn emphasizes model V1 motion activities of matching velocity by excitatory modulation and thus realizes an attentional gating mechanism. The model dynamics implement a guided filling-in process to disambiguate motion signals through biased on-center, off-surround competition. Our model makes predictions concerning the time course of cells in area MT and V1 and the disambiguation process of activity patterns in these areas and serves as a means to link physiological mechanisms with perceptual behavior. We further demonstrate that our model also successfully processes natural image sequences.

The Aperture Problem

2017 ◽  
Author(s):  
Maggie Shiffrar
Keyword(s):  
Visual Perception ◽  
Visual System ◽  
Simple Form ◽  
Moving Objects ◽  
Visual Motion ◽  
Motion Information ◽  
Aperture Problem ◽  
Simultaneous Integration ◽  
Illusory Perception ◽  
True Direction

The accurate visual perception of an object’s motion requires the simultaneous integration of motion information arising from that object along with the segmentation of motion information from other objects. When moving objects are seen through apertures, or viewing windows, the resultant illusions highlight some of the challenges that the visual system faces as it balances motion segmentation with motion integration. One example is the barber pole Illusion, in which lines appear to translate orthogonally to their true direction of emotion. Another is the illusory perception of incoherence when simple rectilinear objects translate or rotate behind disconnected apertures. Studies of these illusions suggest that visual motion processes frequently rely on simple form cues.

Misdirected visual motion: Mae and phi

1991 ◽  
Author(s):  
Eric J. Hiris ◽  
Robert H. Cormack ◽  
Randolph Blake
Keyword(s):  
Visual Motion

Case Report: Management of a Patient with mTBI and Vestibular Hypofunction with the Binasal Occlusion Technique

2018 ◽  
pp. 87-90
Keyword(s):  
Case Report ◽  
Visual Motion ◽  
Hand Movement ◽  
Motion Sensitivity ◽  
Vestibular Hypofunction ◽  
First Case ◽  
Neurological Exam ◽  
History Of ◽  
Occlusion Technique ◽  
Visual Vertigo

Background: Binasal Occlusion (BNO) is a clinical technique used by many neurorehabilitative optometrists in patients with mild traumatic brain injury (mTBI) and increased visual motion sensitivity (VMS) or visual vertigo. BNO is a technique in which partial occluders are added to the spectacle lenses to suppress the abnormal peripheral visual motion information. This technique helps in reducing VMS symptoms (i.e., nausea, dizziness, balance difficulty, visual confusion). Case Report: A 44-year-old AA female presented for a routine eye exam with a history of mTBI approximately 33 years ago. She was suffering from severe dizziness for the last two years that was adversely impacting her ADLs. The dizziness occurred in all body positions and all environments throughout the day. She was diagnosed with vestibular hypofunction and had undergone vestibular therapy but reported little improvement. Neurological exam revealed dizziness with both OKN drum and hand movement, especially in the left visual field. BNO technique resulted in immediate relief of her dizziness symptoms. Conclusion: To our knowledge, this is the first case that illustrates how the BNO technique in isolation can be beneficial for patients with mTBI and vestibular hypofunction. It demonstrates the success that BNO has in filtering abnormal peripheral visual motion in these patients.

Premorbid migraine history as a risk factor for vestibular and oculomotor baseline concussion assessment in pediatric athletes

2019 ◽  
Vol 23 (4) ◽  
pp. 465-470 ◽  
Author(s):  
Ryan N. Moran ◽  
Tracey Covassin ◽  
Jessica Wallace
Keyword(s):  
Risk Factor ◽  
Smooth Pursuit ◽  
Migraine Headache ◽  
Visual Motion ◽  
Assessment Tools ◽  
Motion Sensitivity ◽  
Ocular Reflex ◽  
Migraine Headaches ◽  
Vestibular Ocular Reflex ◽  
History Of

OBJECTIVEMigraine history has recently been identified as a risk factor for concussion and recovery. The authors performed a cross-sectional study examining baseline outcome measures on newly developed and implemented concussion assessment tools in pediatrics. The purpose of this study was to examine the effects of premorbid, diagnosed migraine headaches as a risk factor on vestibular and oculomotor baseline assessment in pediatric athletes.METHODSPediatric athletes between the ages of 8 and 14 years with a diagnosed history of migraine headache (n = 28) and matched controls without a history of diagnosed migraine headache (n = 28) were administered a baseline concussion assessment battery, consisting of the Vestibular/Ocular Motor Screening (VOMS), near point of convergence (NPC), and the King-Devick (K-D) tests. Between-groups comparisons were performed for vestibular symptoms and provocation scores on the VOMS (smooth pursuit, saccades, convergence, vestibular/ocular reflex, visual motion sensitivity), NPC (average distance), and K-D (time).RESULTSIndividuals diagnosed with migraine headaches reported greater VOMS smooth pursuit scores (p = 0.02), convergence scores (p = 0.04), vestibular ocular reflex scores (p value range 0.002–0.04), and visual motion sensitivity scores (p = 0.009). Differences were also observed on K-D oculomotor performance with worse times in those diagnosed with migraine headache (p = 0.02). No differences were reported on NPC distance (p = 0.06) or headache symptom reporting (p = 0.07) prior to the VOMS assessment.CONCLUSIONSPediatric athletes diagnosed with migraine headaches reported higher baseline symptom provocation scores on the VOMS. Athletes with migraine headaches also performed worse on the K-D test, further illustrating the influence of premorbid migraine headaches as a risk factor for elevated concussion assessment outcomes at baseline. Special consideration may be warranted for post-concussion assessment in athletes with migraine headaches.

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