Journal articles: 'Optic flow'

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Raudies, Florian. "Optic flow." Scholarpedia 8, no. 7 (2013): 30724. http://dx.doi.org/10.4249/scholarpedia.30724.

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Koenderink, Jan J. "Optic flow." Vision Research 26, no. 1 (January 1986): 161–79. http://dx.doi.org/10.1016/0042-6989(86)90078-7.

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Pan, Jing Samantha, and Hongyuan Wu. "Identifying blurry scenes with translational optic flow, rotational optic flow or combined optic flow." Journal of Vision 18, no. 10 (September 1, 2018): 1272. http://dx.doi.org/10.1167/18.10.1272.

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Wu, Hongyuan, Xiaoye Michael Wang, and Jing Samantha Pan. "Perceiving blurry scenes with translational optic flow, rotational optic flow or combined optic flow." Vision Research 158 (May 2019): 49–57. http://dx.doi.org/10.1016/j.visres.2018.11.008.

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Kim, Jong-Nam, Kathleen Mulligan, and Helen Sherk. "Simulated Optic Flow and Extrastriate Cortex. I. Optic Flow Versus Texture." Journal of Neurophysiology 77, no. 2 (February 1, 1997): 554–61. http://dx.doi.org/10.1152/jn.1997.77.2.554.

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Kim, Jong-Nam, Kathleen Mulligan, and Helen Sherk. Simulated optic flow and extrastriate cortex. I. Optic flow versus texture. J. Neurophysiol. 77: 554–561, 1997. A locomoting observer sees a very different visual scene than an observer at rest: images throughout the visual field accelerate and expand, and they follow approximately radial outward paths from a single origin. This so-called optic flow field is presumably used for visual guidance, and it has been suggested that particular areas of visual cortex are specialized for the analysis of optic flow. In the cat, the lateral suprasylvian visual area (LS) is a likely candidate. To test the hypothesis that LS is specialized for analysis of optic flow fields, we recorded cell responses to optic flow displays. Stimulus movies simulated the experience of a cat trotting slowly across an endless plain covered with small balls. In different simulations we varied the size of balls, their organization (randomly or regularly dispersed), and their color (all one gray level, or multiple shades of gray). For each optic flow movie, a “texture” movie composed of the same elements but lacking optic flow cues was tested. In anesthetized cats, >500 neurons in LS were studied with a variety of movies. Most (70%) of 454 visually responsive cells responded to optic flow movies. Visually responsive cells generally preferred optic flow to texture movies (69% of those responsive to any movie). The direction in which a movie was shown (forward or reverse) was also an important factor. Most cells (68%) strongly preferred forward motion, which corresponded to visual experience during locomotion.

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Wurtz, Robert H. "Optic flow: A brain region devoted to optic flow analysis?" Current Biology 8, no. 16 (July 1998): R554—R556. http://dx.doi.org/10.1016/s0960-9822(07)00359-4.

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Niehorster, Diederick C. "Optic Flow: A History." i-Perception 12, no. 6 (November 2021): 204166952110557. http://dx.doi.org/10.1177/20416695211055766.

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The concept of optic flow, a global pattern of visual motion that is both caused by and signals self-motion, is canonically ascribed to James Gibson's 1950 book “ The Perception of the Visual World.” There have, however, been several other developments of this concept, chiefly by Gwilym Grindley and Edward Calvert. Based on rarely referenced scientific literature and archival research, this article describes the development of the concept of optic flow by the aforementioned authors and several others. The article furthermore presents the available evidence for interactions between these authors, focusing on whether parts of Gibson's proposal were derived from the work of Grindley or Calvert. While Grindley's work may have made Gibson aware of the geometrical facts of optic flow, Gibson's work is not derivative of Grindley's. It is furthermore shown that Gibson only learned of Calvert's work in 1956, almost a decade after Gibson first published his proposal. In conclusion, the development of the concept of optic flow presents an intriguing example of convergent thought in the progress of science.

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Koenderink, Jan J., and Andrea J. van Doorn. "Second-order optic flow." Journal of the Optical Society of America A 9, no. 4 (April 1, 1992): 530. http://dx.doi.org/10.1364/josaa.9.000530.

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Zimmer, Henning, Andrés Bruhn, and Joachim Weickert. "Optic Flow in Harmony." International Journal of Computer Vision 93, no. 3 (January 26, 2011): 368–88. http://dx.doi.org/10.1007/s11263-011-0422-6.

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Petzold, A. "Optic flow induced nystagmus." Journal of Neurology, Neurosurgery & Psychiatry 76, no. 8 (August 1, 2005): 1173–74. http://dx.doi.org/10.1136/jnnp.2004.052720.

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Koenderink, J. J., and Andrea J. van Doorn. "Facts on optic flow." Biological Cybernetics 56, no. 4 (June 1987): 247–54. http://dx.doi.org/10.1007/bf00365219.

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B N, Shobha, Govind R. Kadambi, S. R. Shankapal, and Yuri Vershinim. "Effect of variation in colour gradient information for optic flow computations." International Journal of Engineering & Technology 3, no. 4 (September 17, 2014): 445. http://dx.doi.org/10.14419/ijet.v3i4.2722.

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Optic flow algorithms provide mapping of 3D velocities on 2D image space. Optic flow is computed on the pair of images which are in sequence and is normally gray scale images. Optic flow computation using Horn and Schunck assumes that brightness consistency is maintained. Colour optic flow has the advantage that optic flow vectors are obtained even when there is a variation of brightness in the input images. The use of colour bands for optic flow is investigated by considering gradients of colour bands and component gradients. Results of applying these two types of gradients to three colour models are presented and analyzed. Decision logic is proposed to select the best colour model for colour optic flow computation based on gradient analysis. Keywords: Activity Measure. Colour Bands, Component Gradients, Decision Logic, Optic Flow Computation.

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Higuchi, Yoko, Satoshi Inoue, Hiroto Hamada, and Takatsune Kumada. "Artificial Optic Flow Guides Visual Attention in a Driving Scene." Human Factors: The Journal of the Human Factors and Ergonomics Society 62, no. 4 (May 24, 2019): 578–88. http://dx.doi.org/10.1177/0018720819847022.

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Objective The objective of this study was to investigate whether an artificial optic flow created by dot motion guides attention in a driving scene. Background To achieve safe driving, it is essential to understand the characteristics of human visual information processing as well as to provide appropriate support for drivers. Past research has demonstrated that expanding optic flow guides visual attention to the focus of expansion. Optic flow is an attractive candidate for use as a cue to direct drivers’ attention toward the significant information. The question addressed concerns whether an artificial optic flow can successfully guide attention even in a traffic situation involving the optic flow that naturally occurs while driving. Method We developed a visual search paradigm embedded in a video of a driving scene. Participants first observed an optic flow motion pattern superimposed on the video for brief period; next, when the optic flow and video ceased, they searched a static display for a target among multiple distractors. Results The target detection was faster when a target’s locus coincided with the implied focus of expansion from the preceding optic flow (vs. other loci). Conclusion The artificial optic flow guides attention and facilitates searching objects at the focus of expansion even when the optic flow was superimposed on a driving scene. Application Optic flow can be an effective cue for guiding drivers’ attention in a traffic situation. This finding contributes to the understanding of visual attention in moving space and helps develop technology for traffic safety.

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Yu, Chen Ping, William K. Page, Roger Gaborski, and Charles J. Duffy. "Receptive Field Dynamics Underlying MST Neuronal Optic Flow Selectivity." Journal of Neurophysiology 103, no. 5 (May 2010): 2794–807. http://dx.doi.org/10.1152/jn.01085.2009.

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Optic flow informs moving observers about their heading direction. Neurons in monkey medial superior temporal (MST) cortex show heading selective responses to optic flow and planar direction selective responses to patches of local motion. We recorded MST neuronal responses to a 90 × 90° optic flow display and to a 3 × 3 array of local motion patches covering the same area. Our goal was to test the hypothesis that the optic flow responses reflect the sum of the local motion responses. The local motion responses of each neuron were modeled as mixtures of Gaussians, combining the effects of two Gaussian response functions derived using a genetic algorithm, and then used to predict that neuron's optic flow responses. Some neurons showed good correspondence between local motion models and optic flow responses, others showed substantial differences. We used the genetic algorithm to modulate the relative strength of each local motion segment's responses to accommodate interactions between segments that might modulate their relative efficacy during co-activation by global patterns of optic flow. These gain modulated models showed uniformly better fits to the optic flow responses, suggesting that coactivation of receptive field segments alters neuronal response properties. We tested this hypothesis by simultaneously presenting local motion stimuli at two different sites. These two-segment stimuli revealed that interactions between response segments have direction and location specific effects that can account for aspects of optic flow selectivity. We conclude that MST's optic flow selectivity reflects dynamic interactions between spatially distributed local planar motion response mechanisms.

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Li, L., and J. C. K. Cheng. "Perceiving path from optic flow." Journal of Vision 11, no. 1 (January 26, 2011): 22. http://dx.doi.org/10.1167/11.1.22.

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Cheng, J., and L. Li. "Perceiving path from optic flow." Journal of Vision 11, no. 11 (September 23, 2011): 908. http://dx.doi.org/10.1167/11.11.908.

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Simpson, William A. "Depth Discrimination from Optic Flow." Perception 17, no. 4 (August 1988): 497–512. http://dx.doi.org/10.1068/p170497.

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A simple scheme for deriving relative depth (time-to-collision, or TTC) from optic flow is developed in which the total flow is first sensed by unconnected motion (imperfect filter) sensors and then the rotational component is subtracted to yield the translational component. Only the latter component yields depth information. This scheme is contrasted with one where the TTC sensors respond only to the translational component at the initial registration of the flow (perfect filter sensors or looming detectors). The simple scheme predicts the results of three experiments on discrimination of TTC: discrimination thresholds are elevated if the objects withdraw from rather than approach the observer, thresholds are elevated if a rotational component is added to the flow, and the amount of threshold elevation resulting from the addition of a rotational component is reduced by prior adaptation to a pure rotational flow. These results confirm the simple model and disconfirm predictions based on the looming detector scheme.

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Campani, Marco, Andrea Giachetti, and Vincent Torre. "Optic Flow and Autonomous Navigation." Perception 24, no. 3 (March 1995): 253–67. http://dx.doi.org/10.1068/p240253.

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Sarma, Pratiksha, Hidam Kumarjit Singh, and Tulshi Bezboruah. "Fiber Optic Capillary Flow Viscometer." IEEE Sensors Letters 3, no. 2 (February 2019): 1–4. http://dx.doi.org/10.1109/lsens.2018.2885312.

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Green, William, and Paul Oh. "Optic-Flow-Based Collision Avoidance." IEEE Robotics & Automation Magazine 15, no. 1 (March 2008): 96–103. http://dx.doi.org/10.1109/mra.2008.919023.

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Kelly, J. W., A. C. Beall, and J. M. Loomis. "Postural control without optic flow." Journal of Vision 3, no. 9 (March 16, 2010): 213. http://dx.doi.org/10.1167/3.9.213.

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Jouen, François, Jean-Claude Lepecq, Olivier Gapenne, and Bennett I. Bertenthal. "Optic flow sensitivity in neonates." Infant Behavior and Development 23, no. 3-4 (March 2000): 271–84. http://dx.doi.org/10.1016/s0163-6383(01)00044-3.

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Aaen-Stockdale, Craig, Tim Ledgeway, and Robert F. Hess. "Second-order optic flow processing." Vision Research 47, no. 13 (June 2007): 1798–808. http://dx.doi.org/10.1016/j.visres.2007.02.022.

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Petrov, Y., and J. Qian. "Optic flow strongly affects brightness." Journal of Vision 10, no. 7 (August 6, 2010): 418. http://dx.doi.org/10.1167/10.7.418.

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Lappe, Markus, and Josef P. Rauschecker. "Heading detection from optic flow." Nature 369, no. 6483 (June 1994): 712–13. http://dx.doi.org/10.1038/369712a0.

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Simpson, William A. "Optic flow and depth perception." Spatial Vision 7, no. 1 (1993): 35–75. http://dx.doi.org/10.1163/156856893x00036.

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Hatzitheodorou, M., E. A. Karabassi, G. Papaioannou, A. Boehm, and T. Theoharis. "Stereo Matching Using Optic Flow." Real-Time Imaging 6, no. 4 (August 2000): 251–66. http://dx.doi.org/10.1006/rtim.1998.0141.

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Parry, David, Camilla Chinnasamy, and Dominic Micklewright. "Optic Flow Influences Perceived Exertion During Cycling." Journal of Sport and Exercise Psychology 34, no. 4 (August 2012): 444–56. http://dx.doi.org/10.1123/jsep.34.4.444.

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Optic flow on the retina creates a perception of a person’s movement relative to their surroundings. This study investigated the effect of optic flow on perceived exertion during cycling. Fifteen participants completed a 20-km reference cycling time trail in the fastest possible time followed by three randomly counterbalanced 20-km cycling trials. Optic flow, via projected video footage of a cycling course, either represented actual speed (TTNORM) or was varied by −15% (TTSLOW) and +15% (TTFAST). During TTSLOW, power output and ratings of perceived exertion (RPE), measured every 4 km, were lower during TTSLOW compared with TTNORM and TTFAST. There were no differences in heart rate or cadence. This study is the first to show that different rates of optic flow influence perceived exertion during cycling, with slower optic flow being associated with lower RPE and higher power output.

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R, Reeja S., and Dr N. P. Kavya. "A System for Movement Detecting Congestion." INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY 13, no. 3 (April 10, 2014): 4302–7. http://dx.doi.org/10.24297/ijct.v13i3.2761.

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In this paper, we present a system for tracking and provide early information of hazardous locationsin huge gatherings. It is based on optic flow estimations and detects sequences of crowd motion that are characteristic for devastating congestions. For optic flow computation, Lucas- Kanade method is employed to determine the optical flow vectors for the gathered video. Segmentation of video sequences is done and optic flow is determined for respective segments. A threshold optic flow is chosen in such a way that the tracking of congested area in video is easilydoneby comparing it with respective segmentâ€™s determined optic flow values. Finally, we present the location of crowd congestion which helps in taking further protective measures to handle unusual events.Â Â

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Duffy, Charles J. "MST Neurons Respond to Optic Flow and Translational Movement." Journal of Neurophysiology 80, no. 4 (October 1, 1998): 1816–27. http://dx.doi.org/10.1152/jn.1998.80.4.1816.

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Duffy, Charles J. MST neurons respond to optic flow and translational movement . J. Neurophysiol. 80: 1816–1827, 1998. We recorded the responses of 189 medial superior temporal area (MST) neurons by using optic flow, real translational movement, and combined stimuli in which matching directions of optic flow and real translational movement were presented together. One-half of the neurons (48%) showed strong responses to optic flow simulating self-movement in the horizontal plane, and 24% showed strong responses to translational movement. Combining optic flow stimuli with matching directions of translational movement caused substantial changes in both the amplitude of the best responses (44% of neurons) and the strength of direction selectivity (71% of neurons), with little effect on which stimulus direction was preferred. However, combining optic flow and translational movement such that opposite directions were presented together changed the preferred direction in 45% of the neurons with substantial changes in the strength of direction selectivity. These studies suggest that MST neurons combine visual and vestibular signals to enhance self-movement detection and disambiguate optic flow that results from either self-movement or the movement of large objects near the observer.

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Burlingham, Charlie S., and David J. Heeger. "Heading perception depends on time-varying evolution of optic flow." Proceedings of the National Academy of Sciences 117, no. 52 (December 16, 2020): 33161–69. http://dx.doi.org/10.1073/pnas.2022984117.

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There is considerable support for the hypothesis that perception of heading in the presence of rotation is mediated by instantaneous optic flow. This hypothesis, however, has never been tested. We introduce a method, termed “nonvarying phase motion,” for generating a stimulus that conveys a single instantaneous optic flow field, even though the stimulus is presented for an extended period of time. In this experiment, observers viewed stimulus videos and performed a forced-choice heading discrimination task. For nonvarying phase motion, observers made large errors in heading judgments. This suggests that instantaneous optic flow is insufficient for heading perception in the presence of rotation. These errors were mostly eliminated when the velocity of phase motion was varied over time to convey the evolving sequence of optic flow fields corresponding to a particular heading. This demonstrates that heading perception in the presence of rotation relies on the time-varying evolution of optic flow. We hypothesize that the visual system accurately computes heading, despite rotation, based on optic acceleration, the temporal derivative of optic flow.

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Eckert, Priska, Max D. Knickmeyer, Lucas Schütz, Joachim Wittbrodt, and Stephan Heermann. "Morphogenesis and axis specification occur in parallel during optic cup and optic fissure formation, differentially modulated by BMP and Wnt." Open Biology 9, no. 2 (February 2019): 180179. http://dx.doi.org/10.1098/rsob.180179.

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Optic cup morphogenesis is an intricate process. Especially, the formation of the optic fissure is not well understood. Persisting optic fissures, termed coloboma, are frequent causes for congenital blindness. Even though the defective fusion of the fissure margins is the most acknowledged reason for coloboma, highly variable morphologies of coloboma phenotypes argue for a diverse set of underlying pathomechanisms. Here, we investigate optic fissure morphogenesis in zebrafish to identify potential morphogenetic defects resulting in coloboma. We show that the formation of the optic fissure depends on tissue flow movements, integrated into the bilateral distal epithelial flow forming the optic cup. On the temporal side, the distal flow translates into a ventral perpendicular flow, shaping the temporal fissure margin. On the nasal side, however, the distal flow is complemented by tissue derived from the optic stalk, shaping the nasal fissure margin. Notably, a distinct population of TGFβ-signalling positive cells is translocated from the optic stalk into both fissure margins. Furthermore, we show that induced BMP signalling as well as Wnt-signalling inhibition result in morphogenetic defects of the optic fissure. Our data also indicate that morphogenesis is crucial for a proper positioning of pre-specified dorsal–ventral optic cup domains.

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Liang, Pei, Roland Kern, Rafael Kurtz, and Martin Egelhaaf. "Impact of visual motion adaptation on neural responses to objects and its dependence on the temporal characteristics of optic flow." Journal of Neurophysiology 105, no. 4 (April 2011): 1825–34. http://dx.doi.org/10.1152/jn.00359.2010.

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It is still unclear how sensory systems efficiently encode signals with statistics as experienced by animals in the real world and what role adaptation plays during normal behavior. Therefore, we studied the performance of visual motion-sensitive neurons of blowflies, the horizontal system neurons, with optic flow that was reconstructed from the head trajectories of semi-free-flying flies. To test how motion adaptation is affected by optic flow dynamics, we manipulated the seminatural optic flow by targeted modifications of the flight trajectories and assessed to what extent neuronal responses to an object located close to the flight trajectory depend on adaptation dynamics. For all types of adapting optic flow object-induced response increments were stronger in the adapted compared with the nonadapted state. Adaptation with optic flow characterized by the typical alternation between translational and rotational segments produced this effect but also adaptation with optic flow that lacked these distinguishing features and even pure rotation at a constant angular velocity. The enhancement of object-induced response increments had a direction-selective component because preferred-direction rotation and natural optic flow were more efficient adaptors than null-direction rotation. These results indicate that natural dynamics of optic flow is not a basic requirement to adapt neurons in a specific, presumably functionally beneficial way. Our findings are discussed in the light of adaptation mechanisms proposed on the basis of experiments previously done with conventional experimenter-defined stimuli.

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Casselbrant, Margaretha L., Ellen M. Mandel, Patrick J. Sparto, Mark S. Redfern, and Joseph M. Furman. "Contribution of Vision to Balance in Children Four to Eight Years of Age." Annals of Otology, Rhinology & Laryngology 116, no. 9 (September 2007): 653–57. http://dx.doi.org/10.1177/000348940711600905.

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Objectives: The use of sensory feedback for postural control develops throughout childhood. The aim of this study was to determine how children use cues from anterior-posterior optic flow for balance from 4 to 8 years of age. Methods: One hundred forty-eight children were enrolled. The subjects had yearly otologic and posturographic examinations between the ages of 4 and 8 years. Balance was assessed only if the subject had no evidence of middle ear effusion. The subject stood for 30 seconds with eyes open without optic flow and for 30 seconds while viewing 0.1, 0.25, and 0.4 Hz anterior-posterior optic flow. The center of pressure (COP) was recorded from the force platform. The root-mean-square of the COP during the periods of quiet stance and with optic flow was computed. Results: The root-mean-square COP was significantly larger during the optic flow stimulation as compared with during quiet stance. The subjects had a significant decrease in COP during optic flow from year 5 to year 6 of life (p = 005). Conclusions: A change in the response to optic flow was seen from age 5 to age 6. This change is consistent with transitional changes in postural responses that have been observed during quiet standing.

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Scholtyssek, Christine, Marie Dacke, Ronald Kröger, and Emily Baird. "Control of self-motion in dynamic fluids: fish do it differently from bees." Biology Letters 10, no. 5 (May 2014): 20140279. http://dx.doi.org/10.1098/rsbl.2014.0279.

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To detect and avoid collisions, animals need to perceive and control the distance and the speed with which they are moving relative to obstacles. This is especially challenging for swimming and flying animals that must control movement in a dynamic fluid without reference from physical contact to the ground. Flying animals primarily rely on optic flow to control flight speed and distance to obstacles. Here, we investigate whether swimming animals use similar strategies for self-motion control to flying animals by directly comparing the trajectories of zebrafish ( Danio rerio ) and bumblebees ( Bombus terrestris ) moving through the same experimental tunnel. While moving through the tunnel, black and white patterns produced (i) strong horizontal optic flow cues on both walls, (ii) weak horizontal optic flow cues on both walls and (iii) strong optic flow cues on one wall and weak optic flow cues on the other. We find that the mean speed of zebrafish does not depend on the amount of optic flow perceived from the walls. We further show that zebrafish, unlike bumblebees, move closer to the wall that provides the strongest visual feedback. This unexpected preference for strong optic flow cues may reflect an adaptation for self-motion control in water or in environments where visibility is limited.

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Wu, Jun, Zijiang J. He, and Teng Leng Ooi. "Visually Perceived Eye Level and Horizontal Midline of the Body Trunk Influenced by Optic Flow." Perception 34, no. 9 (September 2005): 1045–60. http://dx.doi.org/10.1068/p5416.

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The eye level and the horizontal midline of the body trunk can serve, respectively as references for judging the vertical and horizontal egocentric directions. We investigated whether the optic-flow pattern, which is the dynamic motion information generated when one moves in the visual world, can be used by the visual system to determine and calibrate these two references. Using a virtual-reality setup to generate the optic-flow pattern, we showed that judged elevation of the eye level and the azimuth of the horizontal midline of the body trunk are biased toward the positional placement of the focus of expansion (FOE) of the optic-flow pattern. Furthermore, for the vertical reference, prolonged viewing of an optic-flow pattern with lowered FOE not only causes a lowered judged eye level after removal of the optic-flow pattern, but also an overestimation of distance in the dark. This is equivalent to a reduction in the judged angular declination of the object after adaptation, indicating that the optic-flow information also plays a role in calibrating the extraretinal signals used to establish the vertical reference.

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Wylie, Douglas R. W., and Barrie J. Frost. "Complex Spike Activity of Purkinje Cells in the Ventral Uvula and Nodulus of Pigeons in Response to Translational Optic Flow." Journal of Neurophysiology 81, no. 1 (January 1, 1999): 256–66. http://dx.doi.org/10.1152/jn.1999.81.1.256.

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Wylie, Douglas R. W. and Barrie J. Frost. Complex spike activity of Purkinje cells in the ventral uvula and nodulus of pigeons in response to translational optic flow. J. Neurophysiol. 81: 256–266, 1999. The complex spike (CS) activity of Purkinje cells in the ventral uvula and nodulus of the vestibulocerebellum was recorded from anesthetized pigeons in response to translational optic flow. Translational optic flow was produced using a “translator” projector: a mechanical device that projected a translational optic flowfield onto the walls, ceiling, and floor of the room and encompassed the entire binocular visual field. CS activity was broadly tuned but maximally modulated in response to translational optic flow along a “best” axis. Each neuron was assigned a vector representing the direction in which the animal would need to translate to produce the optic flowfield that resulted in maximal excitation. The vector is described with reference to a standard right-handed coordinate system, where the vectors, + x, + y, and + z represent, rightward, upward, and forward translation of the animal, respectively. Neurons could be grouped into four response types based on the vector of maximal excitation. + y neurons were modulated maximally in response to a translational optic flowfield that results from self-motion upward along the vertical ( y) axis. − y neurons also responded best to translational optic flow along the vertical axis but showed the opposite direction preference. The two remaining groups responded best to translational optic flow along horizontal axes: − x + z neurons and − x− z neurons. In summary, our results suggest that the olivocerebellar system dedicated to the analysis of translational optic flow is organized according to a reference frame consisting of three approximately orthogonal axes: the vertical axis, and two horizontal axes oriented 45° to either side the midline. Previous research has shown that the rotational optic flow system, the eye muscles, the vestibular semicircular canals and the postural control system all share a similar spatial frame of reference.

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WINSHIP, IAN R., and DOUGLAS R. W. WYLIE. "Receptive-field structure of optic flow responsive Purkinje cells in the vestibulocerebellum of pigeons." Visual Neuroscience 23, no. 1 (January 2006): 115–26. http://dx.doi.org/10.1017/s0952523806231109.

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Neurons sensitive to optic flow patterns have been recorded in the the olivo-vestibulocerebellar pathway and extrastriate visual cortical areas in vertebrates, and in the visual neuropile of invertebrates. The complex spike activity (CSA) of Purkinje cells in the vestibulocerebellum (VbC) responds best to patterns of optic flow that result from either self-rotation or self-translation. Previous studies have suggested that these neurons have a receptive-field (RF) structure that “approximates” the preferred optic flowfield with a “bipartite” organization. Contrasting this, studies in invertebrate species indicate that optic flow sensitive neurons are precisely tuned to their preferred flowfield, such that the local motion sensitivities and local preferred directions within their RFs precisely match the local motion in that region of the preferred flowfield. In this study, CSA in the VbC of pigeons was recorded in response to a set of complex computer-generated optic flow stimuli, similar to those used in previous studies of optic flow neurons in primate extrastriate visual cortex, to test whether the receptive field was of a precise or bipartite organization. We found that these RFs were not precisely tuned to optic flow patterns. Rather, we conclude that these neurons have a bipartite RF structure that approximates the preferred optic flowfield by pooling motion subunits of only a few different direction preferences.

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Arif, Noor Azie Azura Mohd, Dilla Duryha Berhanuddin, and Abang Annuar Ehsan. "2D Propagation Simulation of Variation Parameters of U-shape Fiber Optic." International Journal of Engineering and Advanced Technology 10, no. 2 (December 30, 2020): 153–58. http://dx.doi.org/10.35940/ijeat.b2082.1210220.

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Fiber optic has extraordinary properties and is suitable in sensor applications due to its special potential. Currently, macro bending characteristics of newly developed hetero core fiber optic element are designed and evaluated. This paper presents the preliminary results obtained from the numerical simulation analysis of the bending sensitivity of U-shape fiber optics toward the 2D electromagnetic wave in terms of mesh, curvature radius, core fiber size, and turn number. Fiber optics with core sizes of 4, 9, 50, and 62.5 μm were designed. In addition, the combination of core diameters 50-4-50, 50-9-50, 62.5-4-62.5, and 62.5-9-62.5 μm is evaluated to compare the outcome of transmission power in terms of hetero core structure of fiber optic. Simulation is performed using COMSOL Multiphysics simulation tool. The developed U-shape fiber optic is designed to sense the distortion of reducing power transmission by comparing input and output power. Results show that the selected mesh depends on the size of geometry bending fiber optics, and fine and finer mesh is the best for U-shape fiber optic. Furthermore, the power flow on the fiber decreases with the decreasing curvature radius and increasing turn number. The fiber with a core size combination of 62.5–4–62.5 um has high sensitivity in terms of loss. The attained results possess higher potential in the field of sensor applications, such as displacement, strain, pressure, and monitoring respiration, on human body. This study serves as a basis for further investigation of nanomaterial coating on fiber optics, thereby enhancing its credibility for sensing.

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Hwang, Alex D., and Eli Peli. "Stereoscopic Three-dimensional Optic Flow Distortions Caused by Mismatches Between Image Acquisition and Display Parameters." Journal of Imaging Science and Technology 63, no. 6 (November 1, 2019): 60412–1. http://dx.doi.org/10.2352/j.imagingsci.technol.2019.63.6.060412.

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Abstract We analyzed the impact of common stereoscopic three-dimensional (S3D) depth distortion on S3D optic flow in virtual reality environments. The depth distortion is introduced by mismatches between the image acquisition and display parameters. The results show that such S3D distortions induce large S3D optic flow distortions and may even induce partial/full optic flow reversal within a certain depth range, depending on the viewer’s moving speed and the magnitude of S3D distortion. We hypothesize that the S3D optic flow distortion may be a source of intra-sensory conflict that could be a source of visually induced motion sickness.

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Mulligan, Kathleen, Jong-Nam Kim, and Helen Sherk. "Simulated Optic Flow and Extrastriate Cortex. II. Responses to Bar Versus Large-Field Stimuli." Journal of Neurophysiology 77, no. 2 (February 1, 1997): 562–70. http://dx.doi.org/10.1152/jn.1997.77.2.562.

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Mulligan, Kathleen, Jong-Nam Kim, and Helen Sherk. Simulated optic flow and extrastriate cortex. II. Responses to bar versus large-field stimuli. J. Neurophysiol. 77: 562–570, 1997. In the preceding paper we described the responses of cells in the cat's lateral suprasylvian visual area (LS) to large-field optic flow and texture movies. To assess response properties such as direction selectivity, cells were also tested with moving bar stimuli. We expected that there would be good agreement between response properties elicited with optic flow movies and those revealed with bar stimuli. We first asked how well bar response properties predicted responsiveness to optic flow movies. There was no correlation between responsiveness to movies and the degree of end-stopping, length summation, or preference for bars that accelerated and expanded. We then considered only the 322 cells that responded to both bars and optic flow or texture movies and asked how well the strength of their response to movies could be predicted from the direction-tuning curves generated with bar stimuli. One-third of these cells responded much more strongly to movies than could be predicted from their direction-tuning curves. Generally, such cells were rather well tuned for the direction of bar motion and preferred a direction substantially different from what they saw in optic flow movies. Optic flow movies shown in the forward direction were the most effective variety of movie for two-thirds of these cells. To see whether this outcome stemmed from differential direction tuning for bars and large multielement displays, in a second series of experiments we compared direction tuning for bars and large-field texture movies. Many cells showed substantially different direction tuning for the two kinds of stimulus: almost [Formula: see text] of 409 cells had tuning curves that overlapped each other by <50%. But only a small number of cells (<10%) responded much better to texture movies than to bars in the predominant direction of image motion in optic flow movies. This result, like that reported in the preceding paper, suggests that cells in LS respond differently to optic flow than to texture displays lacking optic flow motion cues.

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Li, Li, and Diederick C. Niehorster. "Influence of optic flow on the control of heading and target egocentric direction during steering toward a goal." Journal of Neurophysiology 112, no. 4 (August 15, 2014): 766–77. http://dx.doi.org/10.1152/jn.00697.2013.

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Although previous studies have shown that people use both optic flow and target egocentric direction to walk or steer toward a goal, it remains in question how enriching the optic flow field affects the control of heading specified by optic flow and the control of target egocentric direction during goal-oriented locomotion. In the current study, we used a control-theoretic approach to separate the control response specific to these two cues in the visual control of steering toward a goal. The results showed that the addition of optic flow information (such as foreground motion and global flow) in the display improved the overall control precision, the amplitude, and the response delay of the control of heading. The amplitude and the response delay of the control of target egocentric direction were, however, not affected. The improvement in the control of heading with enriched optic flow displays was mirrored by an increase in the accuracy of heading perception. The findings provide direct support for the claim that people use the heading specified by optic flow as well as target egocentric direction to walk or steer toward a goal and suggest that the visual system does not internally weigh these two cues for goal-oriented locomotion control.

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Polikarpova, N. V., and I. K. Chizh. "Acousto-optic devices using acoustic waves refraction." Journal of Physics: Conference Series 2127, no. 1 (November 1, 2021): 012039. http://dx.doi.org/10.1088/1742-6596/2127/1/012039.

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Abstract The methods of acousto-optics provide multiple techniques for controlling optical beam. The technical parameters of corresponding acousto-optic devices are largely determined by the efficiency of acoustic waves generation. In present work we examine the features of elastic waves generation in materials used in acousto-optics. In most of practical applications the elastic wave generation process is implemented through the refraction of elastic waves at the boundary between two anisotropic media. We present a detailed study of the refraction of elastic waves in strongly anisotropic media. We report new refractive effects such as “extraordinary” refraction. In the latter case the change in the direction of the incident acoustic wave does not influence the direction of the energy flow propagation for refracted elastic waves. The configuration of an acousto-optic device using the geometry of unusual refraction in an anisotropic medium is discussed.

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Raffi, Milena, Aurelio Trofè, Andrea Meoni, and Alessandro Piras. "The Speed of Optic Flow Stimuli Influences Body Sway." International Journal of Environmental Research and Public Health 19, no. 17 (August 30, 2022): 10796. http://dx.doi.org/10.3390/ijerph191710796.

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Optic flow is a perceptual cue processed for self-motion control. The aim of this study was to investigate whether postural control is modulated by the speed of radial optic flow stimuli. The experiments were performed on 20 healthy volunteers using stabilometry and surface electromyography (EMG). The subjects were instructed to fixate a central fixation point while radial optic flow stimuli were presented full field, in the foveal and in the peripheral visual field at different dots speed (8, 11, 14, 17 and 20°/s). Fixation in the dark was used as control stimulus. The EMG analysis showed that male and female subjects reacted to the stimuli with different muscle activity (main effects for gender, muscle and laterality: p < 0.001). The analysis of the center of pressure (COP) parameters showed that optic flow stimuli had a different effect on the left and right limbs of males and females (main effects of laterality: p < 0.015; interaction effects of gender and laterality: p < 0.016). The low speed of optic flow stimuli (8 and 11°/s) evoked non-uniform directions of oscillations especially in peripheral stimulation in all subjects, meaning that optic flow simulating slow self-motion stabilizes body sway.

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Elvin, A., T. Andersson, and M. Söderström. "Optic neuritis." Acta Radiologica 39, no. 3 (May 1998): 243–48. http://dx.doi.org/10.1080/02841859809172188.

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Purpose: To establish the role of Doppler ultrasonography (US) in the examination of patients with acute unilateral optic neuritis Material and Methods: Twenty-five patients with a clinical diagnosis of optic neuritis were prospectively evaluated and 18 of them were included in the study. The inclusion criteria were MR findings of unilateral disease and age below 50 years. All patients were examined with MR in order to objectively detect, localize and measure the optic nerve lesions and in order to exclude patients with unidentifiable optic nerve involvement. Evaluation with US was performed to determine nerve morphology, nerve swelling, and resistance to flow in the central retinal artery. The patients' contralateral optic nerve served as an internal control. The US findings were correlated to the degree of visual impairment, both initially and at follow-up Visual evoked potential (VEP) assessments were also performed in 16 patients Results: A statistically significant difference was found in the optic nerve diameter and in the resistance to flow in the central retinal artery between the affected and unaffected eyes. Patients with a prolonged impairment of visual acuity initially had a more swollen nerve and an increased resistance to flow in the affected optic nerve. Prognostic information was also gathered solely by evaluating the unaffected nerve diameter: patients who normally had thinner optic nerves had a more severe form of optic neuritis. VEP assessments were positive in all patients investigated Conclusion: Doppler US can be used together with a VEP assessment as an indicator of the disease process in acute optic neuritis. These methods offer a potential for monitoring patients over time

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Sherk, Helen, Kathleen Mulligan, and Jong-Nam Kim. "Neuronal responses in extrastriate cortex to objects in optic flow fields." Visual Neuroscience 14, no. 5 (September 1997): 879–95. http://dx.doi.org/10.1017/s0952523800011615.

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AbstractDuring locomotion, observers respond to objects in the environment that may represent obstacles to avoid or landmarks for navigation. Although much is known about how visual cortical neurons respond to stimulus objects moving against a blank background, nothing is known about their responses when objects are embedded in optic flow fields (the patterns of motion seen during locomotion). We recorded from cells in the lateral suprasylvian visual area (LS) of the cat, an area probably analogous to area MT. In our first experiments, optic flow simulations mimicked the view of a cat trotting across a plain covered with small balls; a black bar lying on the balls served as a target object. In subsequent experiments, optic flow simulations were composed of natural elements, with target objects representing bushes, rocks, and variants of these. Cells did not respond to the target bar in the presence of optic flow backgrounds, although they did respond to it in the absence of a background. However, 273/423 cells responded to at least one of the taller, naturalistic objects embedded in optic flow simulations. These responses might represent a form of image segmentation, in that cells detected objects against a complex background. Surprisingly, the responsiveness of cells to objects in optic flow fields was not correlated with preferred direction as measured with a moving bar or whole-field texture. Because the direction of object motion was determined solely by receptive-field location, it often differed considerably from a cell's preferred direction. About a quarter of the cells responded well to objects in optic flow movies but more weakly or not at all to bars moving in the same direction as the object, suggesting that the optic flow background modified or suppressed direction selectivity.

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Matthis, Jonathan Samir, Karl S. Muller, Kathryn L. Bonnen, and Mary M. Hayhoe. "Retinal optic flow during natural locomotion." PLOS Computational Biology 18, no. 2 (February 22, 2022): e1009575. http://dx.doi.org/10.1371/journal.pcbi.1009575.

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We examine the structure of the visual motion projected on the retina during natural locomotion in real world environments. Bipedal gait generates a complex, rhythmic pattern of head translation and rotation in space, so without gaze stabilization mechanisms such as the vestibular-ocular-reflex (VOR) a walker’s visually specified heading would vary dramatically throughout the gait cycle. The act of fixation on stable points in the environment nulls image motion at the fovea, resulting in stable patterns of outflow on the retinae centered on the point of fixation. These outflowing patterns retain a higher order structure that is informative about the stabilized trajectory of the eye through space. We measure this structure by applying the curl and divergence operations on the retinal flow velocity vector fields and found features that may be valuable for the control of locomotion. In particular, the sign and magnitude of foveal curl in retinal flow specifies the body’s trajectory relative to the gaze point, while the point of maximum divergence in the retinal flow field specifies the walker’s instantaneous overground velocity/momentum vector in retinotopic coordinates. Assuming that walkers can determine the body position relative to gaze direction, these time-varying retinotopic cues for the body’s momentum could provide a visual control signal for locomotion over complex terrain. In contrast, the temporal variation of the eye-movement-free, head-centered flow fields is large enough to be problematic for use in steering towards a goal. Consideration of optic flow in the context of real-world locomotion therefore suggests a re-evaluation of the role of optic flow in the control of action during natural behavior.

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Kern, Roland, Christian Petereit, and Martin Egelhaaf. "Neural Processing of Naturalistic Optic Flow." Journal of Neuroscience 21, no. 8 (April 15, 2001): RC139. http://dx.doi.org/10.1523/jneurosci.21-08-j0001.2001.

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Bathija, Renuka. "Optic nerve blood flow in glaucoma." Clinical and Experimental Optometry 83, no. 3 (May 2000): 180–84. http://dx.doi.org/10.1111/j.1444-0938.2000.tb04912.x.

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Schrater, Paul R., David C. Knill, and Eero P. Simoncelli. "Perceiving visual expansion without optic flow." Nature 410, no. 6830 (April 2001): 816–19. http://dx.doi.org/10.1038/35071075.

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Journal articles on the topic 'Optic flow'

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