An Eye Tracking based Aircraft Helmet Mounted Display Aiming System

<p>In this paper, we comprehensively present new advancements towards the working-principle, algorithm, prototype setup and experimental characterization and feasibility demonstration of a new aircraft helmet mounted display aiming system. More specifically, we describe detailed design methodology and algorithm of an eye tracking based HMD aiming system. We also present a proof-of-concept prototype and conduct experiment tests in lab environment to characterize the performance of the proposed system. Lastly, through a comparison with related works, we demonstrate the advantages of the proposed HMD system for free head movement and no additional light source required.</p>

An Eye Tracking based Aircraft Helmet Mounted Display Aiming System

<p>In this paper, we comprehensively present new advancements towards the working-principle, algorithm, prototype setup and experimental characterization and feasibility demonstration of a new aircraft helmet mounted display aiming system. More specifically, we describe detailed design methodology and algorithm of an eye tracking based HMD aiming system. We also present a proof-of-concept prototype and conduct experiment tests in lab environment to characterize the performance of the proposed system. Lastly, through a comparison with related works, we demonstrate the advantages of the proposed HMD system for free head movement and no additional light source required.</p>

Blast-induced axonal degeneration in the rat cerebellum in the absence of head movement

Blast exposure can injure brain by multiple mechanisms, and injury attributable to direct effects of the blast wave itself have been difficult to distinguish from that caused by rapid head displacement and other secondary processes. To resolve this issue, we used a rat model of blast exposure in which head movement was either strictly prevented or permitted in the lateral plane. Blast was found to produce axonal injury even with strict prevention of head movement. This axonal injury was restricted to the cerebellum, with the exception of injury in visual tracts secondary to ocular trauma. The cerebellar axonal injury was increased in rats in which blast-induced head movement was permitted, but the pattern of injury was unchanged. These findings support the contentions that blast per se, independent of head movement, is sufficient to induce axonal injury, and that axons in cerebellar white matter are particularly vulnerable to direct blast-induced injury.

Superior colliculus drives stimulus-evoked directionally biased saccades and attempted head movements in head-fixed mice

Animals investigate their environments by directing their gaze towards salient stimuli. In the prevailing view, mouse gaze shifts entail head rotations followed by brainstem-mediated eye movements, including saccades to reset the eyes. These 'recentering' saccades are attributed to head movement-related vestibular cues. However, microstimulating mouse superior colliculus (SC) elicits directed head and eye movements resembling SC-dependent sensory-guided gaze shifts in other species, suggesting that mouse gaze shifts may be more flexible than has been recognized. We investigated this possibility by tracking eye and attempted head movements in a head-fixed preparation that eliminates head movement-related sensory cues. We found tactile stimuli evoke directionally biased saccades coincident with attempted head rotations. Differences in saccade endpoints across stimuli are associated with distinct stimulus-dependent relationships between initial eye position and saccade direction and amplitude. Optogenetic perturbations revealed SC drives these gaze shifts. Thus, head-fixed mice make sensory-guided, SC-dependent gaze shifts involving coincident, directionally biased saccades and attempted head movements. Our findings uncover flexibility in mouse gaze shifts and provide a foundation for studying head-eye coupling.

Speech Act Analysis for Head Movement and Gesture

This research, is entitled (Speech Act Analysis for Head movement and gesture) this study is an attempt to analyze movement and gestures one of the parts of the humans body, which is Head, depending on the conditions and rules of the Speech Acts theory. The research consists of the introduction and two parts as follows:The first part: This part is devoted to the Speech Act theory, highlighting the history of the theory and the diagnosis of its most important features, with a number of classifications for main parts of this theory.The second part: This part is a practical part, which includes a number of movement or Head gestures. We analyzed the gesture or movement according to the theory of Speech Acts and applied the theory to all Head movement with specify the goals of each movement and head gesture.And the search ended with the most important results, with a list of sources.

The perception threshold of the vestibular Coriolis illusion

BACKGROUND: The vestibular Coriolis illusion is a disorienting sensation that results from a transient head rotation about one axis during sustained body rotation about another axis. Although often used in spatial disorientation training for pilots and laboratory studies on motion sickness, little is known about the minimum required rotation rate to produce the illusion. OBJECTIVE: This study determined the perception threshold associated with the Coriolis illusion. METHODS: Nineteen participants performed a standardized pitching head movement during continuous whole-body yaw rotation at rates varying between 5 to 50 deg/s. The participants reported their motion sensation in relation to three hypothesized perception thresholds: 1) any sense of motion, 2) a sense of rotation, and 3) a sense of rotation and its direction (i.e., the factual Coriolis illusion). The corresponding thresholds were estimated from curves fitted by a generalized linear model. RESULTS: On average threshold 1 was significantly lower (8 deg/s) than thresholds 2 and 3. The latter thresholds did not differ from each other and their pooled value was 10 deg/s. CONCLUSIONS: The Coriolis illusion is perceived at yaw rates exceeding 10 deg/s using a pitching head movement with 40 deg amplitude and 55 deg/s peak velocity. Model analysis shows that this corresponds to an internal rotation vector of 6 deg/s. With this vector the Coriolis perception threshold can be predicted for any other head movement.

Co-Speech Movement in Conversational Turn-Taking

This study investigates co-speech movements as a function of the conversational turn exchange type, the type of speech material at a turn exchange, and the interlocutor’s role as speaker or listener. A novel interactive protocol that mixes conversation and (non-read) nursery rhymes works to elicit many speech turns and co-speech movements within dyadic speech interaction. To evaluate a large amount of data, we use the density of co-speech movement as a quantitative measure. Results indicate that both turn exchange type and participant role are associated with variation in movement density for head and brow co-speech movement. Brow and head movement becomes denser as speakers approach overlapping speech exchanges, indicating that speakers increase their movement density as an interruptive exchange is approached. Similarly, head movement generally increases after such overlapping exchanges. Lastly, listeners display a higher rate of co-speech movement than speakers, both at speech turns and remote from them. Brow and head movements generally behave similarly across speech material types, conversational roles, and turn exchange types. On the whole, the study demonstrates that the quantitative co-speech movement density measure advanced here is useful in the study of co-speech movement and turn-taking.

Definiteness in Laki: Its interaction with demonstratives and number

This article investigates definiteness and its interactions with demonstratives and number in Laki (Northwestern Iranian). By the examination of demonstratives and building upon previous proposals, I argue for two types of definite DPs in Laki, namely anaphoric and deictic. I show that the patterns of definite and number marking are sensitive to the type of the DP. In particular, I argue that double definiteness, resulting from an Agree relation between D and N, and head movement of Num to D both are obtained only in anaphoric definite DPs for feature-checking requirements. Overall, this study highlights the contributions of anaphoricity to the DP internal structure. The present proposal can account for similar phenomena in other Iranian languages (i.e., Sorani and Kermanshahi Kurdish). The divergence of Laki definiteness from similar attested patterns (i.e., Scandinavian double definiteness) contributes to our cross-linguistic understanding of definiteness and its interactions with other nominal elements.

Development of a patient-specific immobilisation facemask for radiation therapy using additive manufacturing, pressure sensors and topology optimisation

Purpose Radiotherapy relies on the delivery of radiation to cancer cells with millimetre accuracy, and immobilisation of patients is essential to minimise unwanted damage to surrounding healthy cells due to patient movement. Traditional thermoformed face masks can be uncomfortable and stressful for patients and may not be accurately fitted. The purpose of this study was to use 3D scanning and additive manufacturing to digitise this workflow and improve patient comfort and treatment outcomes. Design/methodology/approach The head of a volunteer was scanned using an Artec Leo optical scanner (Artec, Luxembourg) and ANSYS (Ansys, Canonsburg, USA) software was used to make two 3D models of the mask: one with a nose bridge and one open as would be used with optical surface guidance. Data based on measurements from ten pressure sensors around the face was used to perform topology optimisation, with the best designs 3D printed using fused deposition modelling (FDM) and tested on the volunteer with embedded pressure sensors. Findings The two facemasks proved to be significantly different in terms of restricting head movement inside the masks. The optimised mask with a nose bridge effectively restricted head movement in roll and yaw orientations and exhibited minimal deformation as compared to the open mask design and the thermoformed mask. Originality/value The proposed workflow allows customisation of masks for radiotherapy immobilisation using additive manufacturing and topology optimisation based on collected pressure sensor data. In the future, sensors could be embedded in masks to provide real-time feedback to clinicians during treatment.