Effects of Head Orientation on the Variations in the Discrimination of Shading Orientation

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 278-278
Author(s):  
T R Moshonkina
Keyword(s):  
Eye Movements ◽  
Smooth Surface ◽  
Estimation Error ◽  
Frame Of Reference ◽  
Horizontal Axis ◽  
Head Orientation ◽  
Illumination Direction ◽  
Regular Manner ◽  
The Right ◽  
True Direction

We have previously shown that errors in judging the direction from which a smooth surface is illuminated (ie shading orientation) are not random (Moshonkina et al, 1993 Perception22 Supplement, 100), but vary with this direction in a regular manner. In the experiments described here we investigate whether the same regularities occur when the head is tilted—specifically, whether the gravitational or the head frame of reference is predominantly used in estimation of shading orientation. Stimuli were computer images of spheres (23 deg diameter) presented briefly (for 100 ms, excluding effects of eye movements). The spheres were apparently illuminated from one of 24 directions spaced at equal (15°) intervals around the sphere in the plane of the display. One of these was randomly chosen for each trial. The task was to define the direction of the apparent illumination on a clock scale with half-hour accuracy. The subject's head was either upright or tilted to the left by 30°. Viewing was left monocular. The errors in the estimation of illumination direction showed the same systematic dependence on ‘true’ direction regardless of head orientation. These regularities can be described as follows. (1) Estimates were most accurate when the shading gradient was along the horizontal axis (ie with the illuminated pole of the sphere on the right or the left), with greater errors when the gradient was along the oblique axis or vertical. (2) With oblique shading, the estimates showed a systematic tendency to bring the illumination direction closer to the horizontal axis than in ‘reality’. (3) The largest errors occurred when the illuminated pole was oriented downwards. This suggests that the gravitational frame is important in the discrimination of shading orientation. A significant effect of head orientation was observed when the illuminated pole was oriented downwards. The most probable estimation error was −30° with head upright but −60° with head tilted. This difference is opposite to that expected from application of the head frame of reference.

Clarifying the Rules of the Road

1959 ◽  
Vol 12 (3-4) ◽  
pp. 308-310
Author(s):  
Brett Hilder
Keyword(s):  
Narrow Channel ◽  
Frame Of Reference ◽  
Basic Rule ◽  
Left Hand ◽  
The Road ◽  
Clear Cut ◽  
Single Exception ◽  
Primary Rule ◽  
The Right ◽  
True Direction

The primary Rule of the Road at Sea is to keep to the right in practically all cases. The single exception which comes to mind in regard to fully manœuvrable vessels under power is overtaking in a narrow channel, when the overtaking vessel should keep to port and take the risk of meeting any on-coming traffic, like the working rule on the roads ashore. The alternate use of true direction as a frame of reference at sea, suggested by Lieutenant-Commander N. L. Fendig, U.S.C.G. in this Journal (October 1958) would lead us from simplicity into confusion. The same confusion would apply ashore if the roads were marked with compass courses, and vehicles were to give way to eastern traffic, which would sometimes be on the right, and sometimes on the left hand.The notes by Commander Clissold, R.N.R., under the above heading in the same Journal, are both sensible and workable, but hardly stimulating in nature, as they deal with tedious detail like the rules themselves, without calling for a new outlook. I find the basic Rule of the Road beautifully clear compared with the pages of exceptions and details, most of which show no correlation with each other, or to the basic rules. While I believe that the present rules are the best possible for fully manœuvrable powered vessels, those concerning vessels of limited movement are complicated with confused detail lacking a clear cut system based on relative manœuvrability.

scholarly journals Paradoxical stabilization of relative position in moving frames

2021 ◽  
Author(s):  
Mert Özkan ◽  
Stuart Anstis ◽  
Bernard M. ’t Hart ◽  
Mark Wexler ◽  
Patrick Cavanagh
Keyword(s):  
Eye Movements ◽  
Frame Of Reference ◽  
Moving Frame ◽  
Moving Frames ◽  
Left Edge ◽  
Before And After ◽  
Left And Right ◽  
The Right ◽  
Object Relative ◽  
As If

ABSTRACTTo capture where things are and what they are doing, the visual system may extract the position and motion of each object relative to its surrounding frame of referencee.g., 1,2. Here we report a particularly powerful example where a paradoxical stabilization is produced by a moving frame. We first take a frame that moves left and right and we flash its right edge before, and its left edge after, the frame’s motion. For all frame displacements tested, the two edges are perceived as stabilized, with the left edge on the left and right edge on the right, separated by the frame’s width as if the frame were not moving. This illusory stabilization holds even when the frame travels farther than its width, reversing the actual spatial order of the two flashes. Despite this stabilization, the motion of the frame is still seen, albeit much reduced, and this hides the paradoxical standstill of relative positions. In a second experiment, two probes are flashed inside the frame at the same physical location before and after the frame moves. Despite being physically superimposed, the probes are perceived widely separated, again as if they were seen in the frame’s coordinates and the frame were stationary. This illusory separation is set by the distance of the frame’s travel, independently of its speed. This paradoxical stabilization suggests a link to visual constancy across eye movements where the displacement of the entire visual scene may act as a frame to stabilize the perception of relative locations.

Visual asymmetries during face encoding Increased dwell time and fixations in the upper and left hemifields

2018 ◽  
Author(s):  
Fatima Maria Felisberti
Keyword(s):  
Face Recognition ◽  
Eye Movements ◽  
Visual Field ◽  
Face Processing ◽  
Dwell Time ◽  
The Other ◽  
Environmental Cues ◽  
Reading Habits ◽  
The Right

Visual field asymmetries (VFA) in the encoding of groups rather than individual faces has been rarely investigated. Here, eye movements (dwell time (DT) and fixations (Fix)) were recorded during the encoding of three groups of four faces tagged with cheating, cooperative, or neutral behaviours. Faces in each of the three groups were placed in the upper left (UL), upper right (UR), lower left (LL), or lower right (LR) quadrants. Face recognition was equally high in the three groups. In contrast, the proportion of DT and Fix were higher for faces in the left than the right hemifield and in the upper rather than the lower hemifield. The overall time spent looking at the UL was higher than in the other quadrants. The findings are relevant to the understanding of VFA in face processing, especially groups of faces, and might be linked to environmental cues and/or reading habits.

Interstitial Nucleus of Cajal Encodes Three-Dimensional Head Orientations in Fick-Like Coordinates

2007 ◽  
Vol 97 (1) ◽  
pp. 604-617 ◽  
Author(s):  
Eliana M. Klier ◽  
Hongying Wang ◽  
J. Douglas Crawford
Keyword(s):  
Coordinate System ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Semicircular Canals ◽  
Head Rotation ◽  
Head Orientation ◽  
Interstitial Nucleus Of Cajal ◽  
The Gaze ◽  
Behavioral Constraints ◽  
The Right

Two central, related questions in motor control are 1) how the brain represents movement directions of various effectors like the eyes and head and 2) how it constrains their redundant degrees of freedom. The interstitial nucleus of Cajal (INC) integrates velocity commands from the gaze control system into position signals for three-dimensional eye and head posture. It has been shown that the right INC encodes clockwise (CW)-up and CW-down eye and head components, whereas the left INC encodes counterclockwise (CCW)-up and CCW-down components, similar to the sensitivity directions of the vertical semicircular canals. For the eyes, these canal-like coordinates align with Listing’s plane (a behavioral strategy limiting torsion about the gaze axis). By analogy, we predicted that the INC also encodes head orientation in canal-like coordinates, but instead, aligned with the coordinate axes for the Fick strategy (which constrains head torsion). Unilateral stimulation (50 μA, 300 Hz, 200 ms) evoked CW head rotations from the right INC and CCW rotations from the left INC, with variable vertical components. The observed axes of head rotation were consistent with a canal-like coordinate system. Moreover, as predicted, these axes remained fixed in the head, rotating with initial head orientation like the horizontal and torsional axes of a Fick coordinate system. This suggests that the head is ordinarily constrained to zero torsion in Fick coordinates by equally activating CW/CCW populations of neurons in the right/left INC. These data support a simple mechanism for controlling head orientation through the alignment of brain stem neural coordinates with natural behavioral constraints.

Oocyte and ovary morphological observation of gray wolf (Canis lupus)

2010 ◽  
Vol 60 (3) ◽  
pp. 249-257
Author(s):  
Xu-Guang Liu ◽  
Zhi-Zhong Zhang ◽  
Yun-Hai Zhang ◽  
Yun-Sheng Li ◽  
Fu-Gui Fang ◽  
...  
Keyword(s):  
Histological Examination ◽  
Reproductive System ◽  
Canis Lupus ◽  
Smooth Surface ◽  
Uterine Horn ◽  
Left Ovary ◽  
Morphological Observation ◽  
Gray Wolf ◽  
Antral Follicles ◽  
The Right

AbstractThe present study was carried out to describe the reproductive system of a single adult female wolf, including the uterine horns, cervix, ovaries and follicles. The cumulus oocytes complexes (COCs) and oocytes were also examined. The results showed that the size of each ovary was about 9 × 6 mm with an average of weight of 461.3 mg. The uterus was Y-shaped, and the length of each uterine horn was 14 cm. The distance from the cervix to the bifurcation of the uterine horns was also 14 cm. The left ovary had two large follicles on the surface with a diameter more than 4 mm, while the right ovary had no protuberant follicles. The ovaries were covered with a lot of fat, and were well developed. The COCs derived from the antral follicles were dark, and the nuded oocytes had a dark cytoplasm. The diameter of the oocytes removed from the antral follicles was 116.8 μm on average. The ovaries had a smooth surface and all the follicles were under the surface except for two big follicles on the left ovary. Histological examination of the ovaries by haematoxylin and eosin staining demonstrated that the primordial, primary, preantral and antral follicles were scattered in the cortex, the medulla was abundant with blood vessels. This study preliminarily reveals the features of the wolf reproductive system and the structure of its oocytes and ovaries, which might be indicative for further study and the protection of the species.

scholarly journals The effects of endogenous and exogenus orienting of attention on source memory

2018 ◽  
Vol 8 (2) ◽  
pp. 80-89
Author(s):  
Selene Cansino
Keyword(s):  
Eye Movements ◽  
Episodic Memory ◽  
Source Memory ◽  
Memory Task ◽  
Covert Attention ◽  
Control Mechanisms ◽  
Eye Tracker ◽  
Memory Representations ◽  
The Right ◽  
Symbolic Cues

The aim of this study was to determine the effects of endogenous and exogenous orienting of attention on episodic memory. Thirty healthy participants performed a cueing attention paradigm during encoding, in which images of common objects were presented either to the left or to the right of the center of the screen. Before the presentation of each image, three types of symbolic cues were displayed to indicate the location in which the stimuli would appear: valid cues to elicit endogenous orientation, invalid cues to prompt exogenous orientation and neutral or uncued trials. The participants’ task was to discriminate whether the images were symmetrical or not while fixating on the center of the screen to assure the manifestation of only covert attention mechanisms. Covert attention refers to the ability to orient attention by means of central control mechanisms alone, without head and eye movements. Trials with eye movements were excluded after inspection of eye-tracker recordings that were conducted throughout the task. During retrieval, participants conducted a source memory task in which they indicated the location where the images were presented during encoding. Memory for spatial context was superior during endogenous orientation than during exogenous orientation, whereas exogenous orientation was associated with a greater number of missed responses compared to the neutral trials. The formation of episodic memory representations with contextual details benefits from endogenous attention.

scholarly journals Normal correspondence of tectal maps for saccadic eye movements in strabismus

2016 ◽  
Vol 116 (6) ◽  
pp. 2541-2549 ◽  
Author(s):  
John R. Economides ◽  
Daniel L. Adams ◽  
Jonathan C. Horton
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Superior Colliculus ◽  
Saccadic Eye Movements ◽  
Systematic Change ◽  
Free Viewing ◽  
Pattern Deviation ◽  
Ocular Deviation ◽  
The Right ◽  
Stem Structure

The superior colliculus is a major brain stem structure for the production of saccadic eye movements. Electrical stimulation at any given point in the motor map generates saccades of defined amplitude and direction. It is unknown how this saccade map is affected by strabismus. Three macaques were raised with exotropia, an outwards ocular deviation, by detaching the medial rectus tendon in each eye at age 1 mo. The animals were able to make saccades to targets with either eye and appeared to alternate fixation freely. To probe the organization of the superior colliculus, microstimulation was applied at multiple sites, with the animals either free-viewing or fixating a target. On average, microstimulation drove nearly conjugate saccades, similar in both amplitude and direction but separated by the ocular deviation. Two monkeys showed a pattern deviation, characterized by a systematic change in the relative position of the two eyes with certain changes in gaze angle. These animals' saccades were slightly different for the right eye and left eye in their amplitude or direction. The differences were consistent with the animals' underlying pattern deviation, measured during static fixation and smooth pursuit. The tectal map for saccade generation appears to be normal in strabismus, but saccades may be affected by changes in the strabismic deviation that occur with different gaze angles.

Model-based Head Orientation Estimation for Smart Devices

2021 ◽  
Vol 5 (3) ◽  
pp. 1-24
Author(s):  
Qiang Yang ◽  
Yuanqing Zheng
Keyword(s):  
Radiation Pattern ◽  
Microphone Array ◽  
Estimation Error ◽  
Microphone Arrays ◽  
Smart Devices ◽  
Head Orientation ◽  
Context Information ◽  
Orientation Estimation ◽  
Model Based ◽  
The Voice

Voice interaction is friendly and convenient for users. Smart devices such as Amazon Echo allow users to interact with them by voice commands and become increasingly popular in our daily life. In recent years, research works focus on using the microphone array built in smart devices to localize the user's position, which adds additional context information to voice commands. In contrast, few works explore the user's head orientation, which also contains useful context information. For example, when a user says, "turn on the light", the head orientation could infer which light the user is referring to. Existing model-based works require a large number of microphone arrays to form an array network, while machine learning-based approaches need laborious data collection and training workload. The high deployment/usage cost of these methods is unfriendly to users. In this paper, we propose HOE, a model-based system that enables Head Orientation Estimation for smart devices with only two microphone arrays, which requires a lower training overhead than previous approaches. HOE first estimates the user's head orientation candidates by measuring the voice energy radiation pattern. Then, the voice frequency radiation pattern is leveraged to obtain the final result. Real-world experiments are conducted, and the results show that HOE can achieve a median estimation error of 23 degrees. To the best of our knowledge, HOE is the first model-based attempt to estimate the head orientation by only two microphone arrays without the arduous data training overhead.

Comprehension of Reading Content Using Skimming Techniques to Improve Comprehension of Narrative Text Reading Content in Elementary School Students

Academia Open ◽  
2021 ◽  
Vol 5 ◽  
Author(s):  
Shovana Aulia Paramitha ◽  
Kemil Wachidah
Keyword(s):  
Eye Movements ◽  
Literature Review ◽  
Elementary Students ◽  
Elementary School Students ◽  
Research Method ◽  
Narrative Text ◽  
Good Effect ◽  
School Students ◽  
Text Reading ◽  
The Right

This study aims to determine the effect of using skimming techniques and describe the use of skimming techniques in understanding the reading content of elementary students. This study uses the System Literature Review (SLR) research method. From the results of several studies that have been successfully reviewed, it shows that the use of skimming techniques in understanding reading content is the right technique to use in understanding reading content because skimming techniques can increase students' knowledge of reading more. The use of skimming techniques can be done in the first way, having questions to look for, reading book titles and subtitles, reading with rapid eye movements, understanding sentences in the reading, then being able to draw conclusions. Based on the analysis that has been done, it can be concluded that the use of skimming techniques has a very good effect on students 'reading comprehension and can be an alternative or method to help improve reading content comprehension and broaden students' knowledge.

The three-dimensional stable mandibular landmarks in patients between the ages of 12.5 to 17.1 years

2020 ◽  
Author(s):  
Gui Chen ◽  
Mona Al Awadi ◽  
David William Chambers ◽  
Manuel O Lagravère-Vich ◽  
Tianmin Xu ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Growth Period ◽  
Mandibular Canal ◽  
Mental Foramen ◽  
Three Dimensions ◽  
Head Orientation ◽  
Facial Growth ◽  
Linear Distance ◽  
The Right ◽  
Stable Structures

Abstract Background: With the aid of implants, Björk identified the two-dimensional mandibular stable structures in cephalogram during facial growth. However, we don't know the three-dimensional stable structures exactly. The purpose of this study was to identify the most stable mandibular landmarks in growing patients using three-dimensional images.Methods: The sample was comprised of two cone-beam computed tomography (CBCT) scans taken about 4.6 years apart in 20 growing patients between the ages of 12.5 (T1) to 17.1 years (T2). After head orientation, landmarks were located on the chin (Pog), internal symphysis (Points C, D and E), and mandibular canals, which included the mental foramina (MF and MFA) and mandibular foramina (MdF). The linear distance change between Point C and these landmarks was measured on each CBCT to test stability through time. The reliability of the suggested stable landmarks was also evaluated. Results: The total distance changes between Point C and points D, E, Pog, MF, and MFA were all less than 1.0 mm from T1 to T2. The reliability measures of these landmarks, which were measured by the Cronbach alpha, were above 0.94 in all three dimensions for each landmark. From T1 to T2, distance changes from Point C to the right and left mandibular foramina were respectively 3.39±3.29 mm and 3.03±2.83 mm. Conclusions: During a growth period that averaged 4.6-years, ranging from 11.2 to 19.8 years, the structures that appeared relatively stable and could be used in mandibular regional superimposition included Pog, landmarks on the inferior part of the internal symphysis, and the mental foramen. The centers of the mandibular foramina, the starting points of the mandibular canal, underwent significant changes in the transverse and sagittal dimensions.

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