When the display matters: A multifaceted perspective on 3D geovisualizations

Instant 3D design concept generation and visualization by real-time hand gesture recognition

Renewable energy resources are intermittent and need buffer storage to the bridge time-gap between production and demand peaks. North German Basin has a very large capacity for CAES in saline aquifers and cavities. Replacement of brine by gas in aquifer cause strong changes in electrical resistivity. Previously we have shown the applicability of 2D electric resistivity tomography (ERT) for monitoring sequestered CO2 in these reservoirs. Towards more real world problems, this paper aims at studying resolution of 3D ERT in boreholes for CAES mapping in deep saline aquifers. We used for this 3D surveys 3-9 vertical arrays of borehole electrodes installed surrounding the targets (caprock, aquifer, CAES plume, aquitard). We applied non classical electrode configurations of pseudo (optimized) and real 3D measurements in different boreholes. The results show that the applied 3D technique can generally map the dome structure targets with varying resolution, smearing and artefacts. However, resistivity amplitudes are less correctly recovered. The resolution increases with increasing number of borehole electrode arrays, increasing of layer thicknesses and the a priori fixing of boundaries in the inversion. Optimized 2D arrays have better resolution than the other arrays and thus needs to be developed to real 3D arrays.

Digital representations of the urban environment have constantly increased their complexity:
 starting from fixed chunks of 2D segment depicting the building base to complex data-sets
 comprising several layer of information such as multi-resolution GIS data combined with on field
 3D data acquisition. Cities in particular and urban development in general emerge from the
 bottom up, so crowd is an essential part of the city environment but it is often absent from most
 of the interactive system used to present urban data and landscapes. This paper presents a
 modular, real-time system based on the open-source framework OpenSceneGraph, providing a
 realistic and efficient 3D visualization in real-time of complex animated pedestrians within large
 urban environments, along with tools to visualize, explore and study macroscopic and emerging
 properties. The system allows to represent large crowd simulations or automatized tracking of
 real pedestrians streamed from external applications: the component-based design aims to
 provide efficient workflow for a multi-disciplinary team, including 3D modelers, urban planners,
 computer scientists, experts of crowd dynamics and other professionals. To evaluate quality,
 performance and interaction, the system was applied to the case study of “T-Days” in Bologna
 historical center, using pre-existing 3D open-data assets: some results in terms of performance
 and workflow among different professionals will be presented.

The aim of this study was to quantitatively investigate the impact of stereoscopic three-dimensional (3D) vision on students' performance when compared with that of two-dimensional (2D) vision in a 3D virtual reality (VR) simulator. Twenty-four dental students (second- and fourth-year BDS) were assigned to perform three operative tasks under 3D and 2D viewing conditions on a Virteasy (HRV) simulator. Groups were crossed over and all students performed the same tasks under the alternate viewing conditions. The performance was evaluated by (1) accuracy, (2) outside target area removal, and (3) tooth cutting time, automatically using the generated feedback. Twenty-one participants completed all sessions. The results revealed a statistically significant effect of 3D vision over 2D vision on students' performance in terms of accuracy (p=0.035). Stereoscopic 3D vision showed significant effect on outside target area removal in the first task (p=0.035). Tooth cutting time was the same under both conditions (p=0.766). The findings revealed improvement in accuracy score and reduction in outside target area removal over the course of the experiment under both conditions. Comparing the difference in 3D effect in the early and advanced learning groups revealed no significant difference among the groups (p>0.05). Utilizing stereoscopic 3D vision in the training session improved students' perception of depth which led to more accurate tooth cutting within the target area, and less outside target area removal. However, 3D shows a limited impact on task completion time.

Lower extremity biomechanical parameters during gait are of interest in degenerative pathologies, such as knee osteoarthritis. However, few investigations have looked at the effect of walking speed on knee biomechanics (e.g., moments). METHODS: 10 healthy volunteers (25.6 ± 5.0 years, 1.68 ± 0.11 m, 70.3 ± 18.0 kg) completed 3 trials each of walking at 4 different speeds [preferred (PS), fast (FS), slow (SS), & very slow (VSS)]. The range for each speed was determined by measuring a percentage of the participants PS: FS = (120 ± 5%), SS = (80 ± 5%), and VSS = (50 ± 5%). Speed was determined using timing gates (Power Systems Brower) placed 2.4 meters apart. Data was collected using a motion capture system (VICON, 200Hz) while participants walked across a ~6-meter walkway; 4 in-line force plates (Bertec, 1000Hz) captured ground reaction force. Sagittal and frontal plane kinematics and kinetics at the knee were calculated for the 4 speeds using Visual 3D. Differences between the 4 speeds were analyzed using a repeated-measures GLM with pairwise comparisons (p<0.05). RESULTS: Average speed for the 4 conditions were: PS = 1.06 ± .17 m/s, FS = 1.29 ± .21 m/s, SS = .90 ± .16 m/s, and VSS = .73 ± .11 m/s. There was a significant main effect for speed (F2, 8 = 28.7, p = 0.034). Pairwise comparisons indicated a statistically significant difference in knee flexor moment for PS versus FS (PS = .181 ± .019, FS = .079 ± .015, p < .05) as well as in knee internal adductor moment for FS versus PS, SS, and VSS (FS = .026 ± .083, PS = -.437 ± .068, SS = -.579 ± .170, VSS = -.363 ± .112, p < .05). Knee flexor moments were smaller for FS versus PS, while FS was also smaller than PS, SS, and VSS for the knee adductor moment. CONCLUSION: Our findings agree with previous research that identified differences in knee flexor and adductor moments at different gait speeds. For pathological populations it is important to understand the effect of gait speed on knee adductor moment since it is a surrogate measure for joint loading. However, our sample size was small; therefore, the effect of gait speed on knee flexor and adductor moments should be further investigated. Future studies will seek to understand the relative contribution of the quadriceps’s muscles at different speeds and its impact on knee joint loads.

SIR–We would like to thank Professor Vles for his in-depth comments on our systematic review on the use of intrathecal baclofen in ambulant children and adolescents with spasticity of cerebral origin.1 In our literature search, we found two studies published by Hoving et al2, 3 on the same group of participants. The first paper was a randomized controlled trial (RCT) investigating the efficacy of intrathecal baclofen on children with spastic cerebral palsy (CP) compared with traditional intervention.2 The second paper was a longitudinal follow-up study on the same group of children, who eventually all had an implanted intrathecal baclofen pump. This second paper examined the 2-year safety and 1-year efficacy of intrathecal baclofen using the same outcome measures, namely visual analogue scales assessing individually formulated problems (e.g. ease of care and pain), Gross Motor Function Measure 66 (GMFM-66) for gross motor function, Pediatric Evaluation of Disability Inventory for activities and participation, and Child Health Questionnaire-Parent Form 50 for quality of life.3 We decided to include the latter in our systematic review as it provided more data on the gross motor function of the participants and had a larger sample size than the previous paper. However, the latter study was a case series as it pooled both the intervention and control groups from the previous RCT into one group for data analyses, thus the level of evidence for this study is level IV.4, 5 In the process of preparing this reply, we found an error in Table II of our paper regarding the study by Hoving et al.3 under the heading of ‘Gross motor activities’: the number inside the second bracket should be ‘12/12 with 11 non-ambulant’, not 17/17 as there was only one ambulant participant in the group of 12 participants who were assessed and showed statistically significant improvement in this area with the GMFM-66. Thus the sentence in the last paragraph on page 7 starting ‘Gross motor skills as measured using the GMFM were significantly improved in three studies … (n=51/51 in total)’ should read ‘(n=46/46 in total including 11 non-ambulant participants)’.3 Although the number of participants has changed, the conclusions have not. We are pleased to have been able to correct this error. We acknowledge there was only one participant in this study3 at Gross Motor Function Classification System (GMFCS) level III, which was explicitly stated in the supplementary online table (Table SIII) in our paper. Only this child was included in our review, a similar strategy was used for other studies in the review (Table SIII and Table II). Our clinical question was to review the evidence for the use of intrathecal baclofen on transfers between positions, gross motor activities, and walking in ambulant children with CP. No data were provided on this child’s ambulatory status and quality of gait in the paper so this child was not included in our discussion regarding these outcomes. This child was included in our discussion on gross motor activities as group data on the score of the sitting dimension of the GMFM-66 was provided.3 We do not believe that our conclusion contradicts the consensus statement by Dan et al.6 regarding the work of Hoving et al.3 The conclusion on the efficacy of intrathecal baclofen (when compared with traditional intervention) drawn by Dan et al.6 was specifically on children with severe CP (as participants in the RCT quoted by Dan et al. were at GMFCS levels IV and V6). Our conclusion of the review was specifically on individuals at GMFCS levels I to III. At present, there is no RCT examining the efficacy of intrathecal baclofen on this ambulant group. In addition, as discussed above, the fact that this follow-up study was not an RCT further strengthens our recommendation for high quality rigorous studies on this intervention in the future. It was never our intention to discourage the use of intrathecal baclofen for children with intractable spastic CP; in fact we strongly support the use of intrathecal baclofen for spasticity and/or dystonia in GMFCS levels IV and V.7, 8 As stated in the consensus statement by Dan et al.,6‘the efficacy of ITB has been less well studied in patients in GMFCS levels I–III than in patients at levels IV–V’. We consider our review a step towards identifying existing research gaps for this intervention in this specific population group. We would encourage more rigorous longitudinal studies in the future that provide evidence for ‘identification of the ideal patient for this treatment’.8 We also hope this review will provide research evidence to families (and clinicians) to make an informed decision about interventions for their children.

Retrospective cohort. To compare robotics and navigation for minimally invasive elective lumbar fusion in terms of radiation exposure and time demand. Although various studies have been conducted to demonstrate the benefits of both navigation and robotics over fluoroscopy in terms of radiation exposure, literature is lacking in studies comparing robotics versus navigation. Patients who underwent elective one-level or two-level minimally invasive transforaminal lumbar interbody fusion (TLIF) by a single surgeon using navigation (Stryker SpineMask) or robotics (ExcelsiusGPS) were included (navigation 2017-2019, robotics 2019-2021, resulting in prospective cohorts of consecutive patients for each modality). All surgeries had the intraoperative computed tomography workflow. The two cohorts were compared for radiation exposure [fluoroscopy time and radiation dose: image capture, surgical procedure, and overall) and time demand (time for setup and image capture, operative time, and total operating room (OR) time]. A total of 244 patients (robotics 111, navigation 133) were included. The two cohorts were similar in terms of baseline demographics, primary/revision surgeries, and fusion levels. For one-level TLIF, total fluoroscopy time, total radiation dose, and % of radiation for surgical procedure were significantly less with robotics compared with navigation (20 vs. 25s, P <0.001; 38 vs. 42mGy, P =0.05; 58% vs. 65%, P =0.021). Although time for setup and image capture was significantly less with robotics (22 vs. 25min, P <0.001) and operative time was significantly greater with robotics (103 vs. 93min, P <0.001), there was no significant difference in the total OR time (145 vs. 141min, P =0.25). Similar findings were seen for two-level TLIF as well. Robotics for minimally invasive TLIF, compared with navigation, leads to a significant reduction in radiation exposure both to the surgeon and patient, with no significant difference in the total OR time.

Principles of stereoscopic vision have long been used in geographic data processing and visualization, e.g. Laussedat created what he called metrophotography in 1895 [2][3] and a stereoautograph for plotting from terrestrial photographs was produced in 1911 [2]. Today, a common and established use of stereoscopy in geographic domain is three-dimensional (3D) modeling of terrains and cities based on aerial, satellite and/or terrestrial imagery with photogrammetric techniques. In these systems, commonly, stereoscopic imagery is used as an input and a vector 3D representation of the terrain or city is obtained as an output. Stereoscopy has also been used for close-range photogrammetry, however within the scope of this paper the focus is on the cartographic use of stereoscopic visualizations. In recent years, a number of mainstream digital devices with stereoscopic capabilities are marketed (e.g. [4], [5], [6]), which indicates that we can expect to see more stereoscopic content in the near future [1]. In anticipation of such a development, it is also plausible to expect that stereoscopic geo-data will become more available for everyday use. It is, therefore, interesting to document which stereoscopic visualization features are supported by mainstream geographic information systems (GIS) software and whether these features can be improved. This work presents a survey on current stereoscopic visualization support in geographic information (GI) systems. The underlying objective is to outline future research needs by examining current stereoscopic 3D visualization techniques and tools in current GISs. This paper focuses on visualization modules of GIS software, and tries to answer the question “How commonly is stereoscopic visualization supported in GIS?" To achieve this, first whether such support exits or not in GIS software is documented, then supported types of stereoscopic operations and viewing methods are reported. Motivated by improving efficiency of stereoscopic visualizations in cartographic domain, within this survey, it is also examined whether these software offer level of detail (LOD) management support for stereoscopic datasets. Findings from the study are meant as a guide to researchers and practitioners to assess the current state of True 3D support in widely used GIS software.

The utility of three-dimensional (3D) kinematic motion analysis systems is limited in rodents. Part of the reason for this inadequacy is the use of complex algorithms and mathematical modeling that accompany 3D data collection and analysis procedures. This work provides a simple, user-friendly, step-by-step detailed methodology for 3D kinematic gait analysis during treadmill locomotion in healthy and neurotraumatic rats using a six-camera motion capture system. Also provided are details on 1) calibration of the system in an experimental set-up customized for quadrupedal locomotion, 2) data collection for treadmill locomotion in adult rats using markers positioned on all four limbs, 3) options available for video tracking and processing, and 4) basic 3D kinematic data generation and visualization and quantification of data using the built-in data collection software. Finally, it is suggested that the utility of this motion capture system be expanded to studying a variety of motor behaviors before and after neurotrauma.

Binocular disparity provides one of the important depth cues within stereoscopic three‐dimensional (3D) visualization technology. However, there is limited research on its effect on learning within a 3D augmented reality (AR) environment. This study evaluated the effect of binocular disparity on the acquisition of anatomical knowledge and perceived cognitive load in relation to visual‐spatial abilities. In a double‐center randomized controlled trial, first‐year (bio)medical undergraduates studied lower extremity anatomy in an interactive 3D AR environment either with a stereoscopic 3D view (n = 32) or monoscopic 3D view (n = 34). Visual‐spatial abilities were tested with a mental rotation test. Anatomical knowledge was assessed by a validated 30‐item written test and 30‐item specimen test. Cognitive load was measured by the NASA‐TLX questionnaire. Students in the stereoscopic 3D and monoscopic 3D groups performed equally well in terms of percentage correct answers (written test: 47.9 ± 15.8 vs. 49.1 ± 18.3; P = 0.635; specimen test: 43.0 ± 17.9 vs. 46.3 ± 15.1; P = 0.429), and perceived cognitive load scores (6.2 ± 1.0 vs. 6.2 ± 1.3; P = 0.992). Regardless of intervention, visual‐spatial abilities were positively associated with the specimen test scores (η2 = 0.13, P = 0.003), perceived representativeness of the anatomy test questions (P = 0.010) and subjective improvement in anatomy knowledge (P < 0.001). In conclusion, binocular disparity does not improve learning anatomy. Motion parallax should be considered as another important depth cue that contributes to depth perception during learning in a stereoscopic 3D AR environment.

Outrigger canoeists adopt a variety of racing stroke rates without scientific basis. The aim of this study was to compare the effect of self-selected and imposed slow (Hawaiian) and fast (Tahitian) stroke rates on 1000-m outrigger ergometer performance and physiological demand to determine which stroke rate was best for performance. Female outrigger canoeists (n=17) completed 1000-m ergometer time trials using a self-selected, Hawaiian (≤55 strokes · min−1) and Tahitian (≥65 strokes · min−1) stroke rate. Performance time and physiological demand were compared for the overall 1000 m and for each 250-m split across trials. There was no significant difference in performance time between the Hawaiian (mean value 358 s, s=30) and Tahitian (mean value 357 s, s=28) trials with both trials significantly faster than the self-selected trial (mean value 371 s, s=38) (P < 0.05). The Hawaiian trial resulted in significantly lower physiological demand than the Tahitian and self-selected trials. When choosing their stroke rate, female outrigger canoeists perform sub-optimally. The Hawaiian stroke rate resulted in the same performance time as the Tahitian stroke rate but with reduced physiological demand. Outrigger canoe coaches should employ a slower stroke rate of ≤ 55 strokes · min−1 to optimize 1000-m performance and minimize physiological demand that may lead to fatigue across multiple races.

Simulators are being used to teach laparoscopic skills before residents get to the operating room. It is unknown whether the use of three-dimensional (3D) vision will facilitate laparoscopic training. Therefore, our objective was to compare the effectiveness of using 3D imaging over the traditional two-dimensional (2D) imaging to teach laparoscopic simulator skills to novice individuals and assess whether 3D imaging ameliorates laparoscopic performance for surgeons who have already adapted to working within a 2D surgical environment. This prospective study involved 36 surgical residents and students. Inexperienced participants included medical students and first- and second-year surgical residents (n = 25). Experienced participants included third- and fifth-year surgical residents (n = 11). Participants were tested on six laparoscopic skills using 2D or 3D imaging systems and then retested about 3 months later using the opposing imaging system. Evaluation of performance was based on the time elapsed to task completion and the errors committed during that time. The experienced participants performed better than the inexperienced participants regardless of the imaging system. Inexperienced participants initially tested using 2D imaging required significantly more time and/or made more errors to complete five of the six laparoscopic tasks compared to those initially tested using 3D imaging (p < 0.05). After initial testing on 3D imaging, inexperienced participants retested using 2D imaging performed significantly better on five of six tasks compared to the scores of inexperienced participants initially tested on 2D imaging (p < 0.05). In contrast, the inexperienced participants' retested on 3D after initial 2D imaging did not improve on any laparoscopic task compared to the scores of inexperienced participants initially tested on 3D imaging. Among the experienced participants, no significant difference in time or errors to task completion was observed under 2D imaging compared to 3D imaging during the first or second testing session. Our study indicates that 3D imaging offers significant advantages in the teaching of laparoscopic skills to inexperienced individuals.

: Nearly one million Americans suffer from chronic fatigue syndrome (CFS). More than 15% of Gulf War veterans (GWV) were found to have CFS. The disease significantly reduces work production of civilian patients and combat ability/readiness of US military forces. Increasing scientific evidence suggests that CFS is a biological illness involving pathology of the central nervous system (CNS). However, little is known about how the CNS is affected by CFS. This study will focus on evaluating brain activities of CFS patients during fatigue and non-fatigue muscle exercises. Our hypothesis is that the brain activation pattern in CFS differs from that of healthy controls. Aim 1 of the study is to determine brain activation patterns during motor activity in CFS patients using functional magnetic resonance imaging. Aim 2 is to examine brain activation patterns during motor activity in CFS patients by analyzing signals of electroencephalograms. Aim 3 is to evaluate signal relationships among different brain regions and between the brain and muscle. Measurements will be made from four groups of participants: a civilian CFS group, a civilian control group, a GWV CFS group, and a GWV control group. We expect that the study will provide objective information for diagnosis of CFS.

The current study was conducted to provide normative data on actigraphic dichotomy index (I < O) (the percentage of in bed activity counts that are less than the median of out of bed counts) in healthy population and to assess whether the I < O could be an effective index in discriminating the circadian motor activity of cancer patients from healthy controls. In this retrospective study, we recovered 408 actigraphic records from two databases: healthy controls (n = 182; 79 males; mean age 38.7 ± 12.6) and patients with metastatic colorectal cancer (n = 226; 149 males; mean age 58.4 ± 11.4). Beside the usual actigraphic sleep parameters (time in bed, sleep onset latency, total sleep time, wake after sleep onset, sleep efficiency, number of awakenings, and mean motor activity), we also computed the dichotomy index and number of actigraphic wake parameters, namely, diurnal motor activity, diurnal total sleep time, number of sleep episodes, and the mean duration of the longest diurnal sleep episode. Using the Youden index, we calculated the cut off value that performed the best for I < O and actigraphic wake parameters. Finally, we created Receiver Operator Characteristic curves to test the efficacy of each actigraphic parameter to discriminate cancer patient from healthy controls. Mean I < O was 99.5% (SD, 0.48%) in the healthy group, as compared to 96.6% (SD, 3.6%) in the cancer group (p < 0.0001). Important age-related effects appeared unlikely after performing both the main analysis with age as a covariate, and a subset analysis in 104 subjects matched for age and sex. In the main analysis, all actigraphic parameters, except total sleep time, significantly differentiated the two groups of participants. However, the I < O was the one that clearly performed best. Here, we provide the first large dataset on I < O in healthy subjects, we confirm the relevance of this circadian index for discriminating advanced stage colorectal cancer patients from healthy subjects, and we lay the grounds for further investigations of this circadian index in patients with other chronic diseases.

We introduce a novel 3D gaze-guided robotic scrub nurse (RN) and test the platform in simulated surgery to determine usability and acceptability with clinical teams. Surgeons and trained scrub nurses performed an ex vivo task on pig colon. Surgeons used gaze via wearable eye-tracking glasses to select surgical instruments on a screen, in turn initiating RN to deliver the instrument. Comparison was done between human- and robot-assisted tasks (HT vs RT). Real-time gaze-screen interaction was based on a framework developed with synergy of conventional wearable eye-tracking, motion capture system and RGB-D cameras. NASA-TLX and Van der Laan’s technology acceptance questionnaires were collected and analyzed. 10 teams of surgical trainees (ST) and scrub nurses (HN) participated. Overall, NASA-TLX feedback was positive. ST and HN revealed no statistically significant difference in overall task load. Task performance feedback was unaffected. Frustration was reported by ST. Overall, Van der Laan’s scores showed positive usefulness and satisfaction scores following RN use. There was no significant difference in task interruptions across HT vs RT. Similarly, no statistical difference was found in duration to task completion in both groups. Quantitative and qualitative feedback was positive. The source of frustration has been understood. Importantly, there was no significant difference in task workflow or operative time, with overall perceptions towards task performance remaining unchanged in HT vs RT.