0000000000526654
AUTHOR
Tatjana Pladere
Binocular function measures as predictors of user performance in stereoscopic augmented reality
Inconsistency between the binocular and focus cues in stereoscopic augmented reality overburdens the visual system leading to its stress. However, a high individual variability of tolerance for visual stress makes it difficult to predict and generalize the user gain associated with the implementation of alternative visualization technologies. In this study, we investigated the relationship between the binocular function and perceptual judgments in augmented reality. We assessed the task completion time and accuracy of perceptual distance matching depending on the consistency of binocular and focus cues in the stereoscopic environment of augmented reality. The head-mounted display was driven…
Impact of viewing distance on relative depth judgements for stimuli in physical space
In natural viewing, numerous depth cues are available to the visual system, but their significance varies considerably depending on the viewing distance. How is it reflected in the outcome of depth judgements? We have designed a psychophysical experiment with a limited number of depth cues to examine distance-related changes in the correct response rate and time. Twenty young adults evaluated relative depth of stimuli in physical space. Each time four constant angular size achromatic stimuli were presented on a volumetric multi-planar display. One of these stimuli was demonstrated closer to the observer comparing to others. The experiment followed the four-interval forced-choice procedure. …
Visual Search Performance Depending on Target-Distractor Difference on Volumetric Display and Flat Panel Display
The search items were demonstrated on the volumetric display and flat panel display. In contrast to the correct response rate, the search time and number of interactions were considerably affected by the type of visualization.
Uzmanība un darba spējas tuvumā atkarībā no stimula perifērijā
Bakalaura darbs uzrakstīts latviešu valodā uz 43 lappusēm, satur 15 attēlus, 1 tabulu un 27 atsauces uz literatūras avotiem. Darba mērķis ir noteikt, vai perifēro stimulu klātbūtne ietekmē uzmanību un perifērās redzes uztveri Metode: tika izmantots meklēšanas veida uzdevums ar dažāda veida perifēriem stimuliem Secinājumi: 1. Perifēro stimulu pamanīt būtiski grūtāk uz fona ar lielu troksni, bet būtiski vieglāk pie lielāka tā izmēra (p<0,05) 2. Perifērā stimula izmēra palielināšanās būtiski uzlaboja tā formas atšķiršanu (p<0,05). Perifērais troksnis būtiski apgrūtināja perifērā stimula formas atšķiršanu (p<0,05) 3. Četri eksperimenta dalībnieki centrālo uzdevumu uz fona ar lielu troksni pilda…
Vizuālās efektivitātes novērtējums uz volumetriskā daudzplakņu ekrāna
Promocijas darba pētījumā tiek izstrādāta metode vizuālās efektivitātes novērtēšanai uz volumetriskā daudzplakņu ekrāna. Redzes uztveres izpēte cilvēkiem meklējot informāciju uz ekrāna norāda, ka, samazinoties mērķa elementa redzamībai, pieaug nepieciešamība izskatīt trīsdimensionālu attēlu selektīvi, kas atspoguļojas attēlu izskatīšanas stratēģijā. Turklāt attēlu izskatīšanas stratēģiju ietekmē profesionālās meklēšanas pieredze radioloģijā. Attēla dziļuma uztveri nosaka mērķa-distraktora līdzība binokulārajā disparitātē, kura ir atkarīga no redzes sistēmas funkcionalitātes un ekrāna optiskā elementa arhitektūras. Atslēgvārdi: vizuālā meklēšana, attēlu izskatīšanas stratēģija, mērķa-distrak…
Ocular performance evaluation
Real and virtual three-dimensional (3D) imaging has found useful applications across different areas of health sciences and with the current rapidly progressive development stage we can expect that the use of 3D imaging soon will be a part of a daily visual load for medical personnel. To better understand the possible impact of prolonged work with 3D content on eye accommodative response and pupil size we compared two 3D imaging techniques - volumetric display that is real voxel-based system and anaglyph technique that is virtual pixel-based system. We have investigated accommodative lag and pupil responses in 38 emmetropic young adult after prolonged visual task with volumetric 3D display …
Focusing in Depth: Post-Task Accommodation Shifts After Sustained Near Work with Volumetric Multi-Planar Display
Post-task refraction shifts were evaluated with eccentric photorefraction technique to better understand response of visual system and eye accommodation to sustained near work with 3D image formed by volumetric display.
When virtual and real worlds coexist: Visualization and visual system affect spatial performance in augmented reality
New visualization approaches are being actively developed aiming to mitigate the effect of vergence-accommodation conflict in stereoscopic augmented reality; however, high interindividual variability in spatial performance makes it difficult to predict user gain. To address this issue, we investigated the effects of consistent and inconsistent binocular and focus cues on perceptual matching in the stereoscopic environment of augmented reality using a head-mounted display that was driven in multifocal and single focal plane modes. Participants matched the distance of a real object with images projected at three viewing distances, concordant with the display focal planes when driven in the mu…
Looking in Depth: Visual Distance Perception of Stimuli on Volumetric Multi-Planar Display
Ability to distinguish relative location of visual stimuli on a multi-planar display was evaluated within psychophysical experiment in order to figure out the impact of physical distance between stimuli across depth of volumetric data.
Visual search in three-dimensional non-medical images: visual-motor performance of radiologists
The visual search abilities of radiologists are systematically trained due to the specifics of their professional tasks. We investigated whether the visual-motor performance of radiologists, residents and students varied when searching non-medical targets on the volumetric display. As a result, no significant differences were found in the correct response rate among three groups. However, the total number of interactions was considerably higher for the resident radiologists and medical students comparing to the experienced radiologists. Our results suggest that the radiological experience does not interfere with the outcome in the developed visual search task, but may be reflected in motor …
Assessment of spatial perception for a multi-layer volumetric display: the effect of exocentric and egocentric distance on relative depth judgements
Three-dimensional images on multiple depth layers of the volumetric display provide the physiological depth cues which ensure the high precision of depth judgements at close viewing distances and enhance the user experience. However, the contribution of physiological cues declines with an increase of viewing distance (egocentric distance), and the human spatial perception varies depending on the inter-stimuli distance (exocentric distance). We conducted a psychophysical experiment to test the perception of three-dimensional images rendered on the volumetric display depending on exocentric and egocentric stimuli distance. The constant angular size visual stimuli were displayed on different d…
Visual grouping under isoluminant condition: impact of mental fatigue
Instead of selecting arbitrary elements our visual perception prefers only certain grouping of information. There is ample evidence that the visual attention and perception is substantially impaired in the presence of mental fatigue. The question is how visual grouping, which can be considered a bottom-up controlled neuronal gain mechanism, is influenced. The main purpose of our study is to determine the influence of mental fatigue on visual grouping of definite information – color and configuration of stimuli in the psychophysical experiment. Individuals provided subjective data by filling in the questionnaire about their health and general feeling. The objective evidence was obtained in t…
Uzmanības un acu kustību raksturlielumi meklēšanas uzdevumā
Maģistra darbs „Uzmanības un acu kustību raksturlielumi meklēšanas uzdevumā” uzrakstīts latviešu valodā, uz 36 lappusēm, satur 9 attēlus, 1 tabulu un 52 atsauces uz literatūras avotiem. Darba mērķis: novērtēt perifērās informācijas ietekmi uz uzmanību un acu kustībām meklēšanas uzdevumā. Metode: astoņi indivīdi pildīja vizuālās meklēšanas uzdevumu ar dažādu perifērās informācijas saturu acu kustību pieraksta laikā, izmantojot iViewX HiSpeed 500 Hz okulogrāfu. Rezultāti: Palielinoties perifērās informācijas daudzumam vizuālās meklēšanas uzdevumā, vidējais fiksāciju skaits samazinās, bet vidējais fiksācijas ilgums un sakāžu amplitūda pieaug, tādēļ nepieciešams ilgāks laiks viena mērķa atrašan…
Comparative assessment of brain activity during depth perception of stereoscopic and volumetric images
Recent advancements in visualization systems have triggered a growing demand for the objective and accurate comparison of user cognitive requirements when perceiving three-dimensional images demonstrated in different ways. In this work, we present the first comparative assessment of brain activity in subjects viewing stereoscopic images and volumetric images. Electroencephalography was employed to assess the short-term changes in event related potentials and neural oscillations which were further interpreted in terms of cognitive requirements for relative depth judgments. As a result, considerably higher activity have been registered in the beta band and gamma band in case of judging relati…