Transparent effect on the gray scale perception of a transparent OLED display

Gray scale perception of transparent OLED displays was explored. The difference in luminance between transparent and non-transparent stimuli in the overall gray range was compared. The transparent effect appeared in gray scale perception. The range of the transparent effect was determined experimentally. To explore the practical application of this effect, we proposed a new tone-curve based on the transparent effect. In the preference experiment, participants indicated a higher preference score for the new tone-curve. This implied that the transparent effect is valid and applicable to real situations

Visualization of uncertainty in natural hazards assessments using an interactive cartographic information system

Natural hazard assessments are always subject to uncertainties due to missing knowledge about the complexity of hazardous processes as well as their natural variability. Decision-makers in the field of natural hazard management need to understand the concept, components, sources, and implications of existing uncertainties in order to reach informed and transparent decisions. Until now, however, only few hazard maps include uncertainty visualizations which would be much needed for an enhanced communication among experts and decision-makers in order to make informed decisions possible. In this paper, an analysis of how uncertainty is currently treated and communicated by Swiss natural hazards experts is presented. The conducted expert survey confirmed that the communication of uncertainty has to be enhanced, possibly with the help of uncertainty visualizations. However, in order to visualize the spatial characteristics of uncertainty, existing uncertainties need to be quantified. This challenge is addressed by the exemplary simulation of a snow avalanche event using a deterministic model and quantified uncertainties with a sensitivity analysis. Suitable visualization methods for the resulting spatial variability of the uncertainties are suggested, and the advantages and disadvantages of their implementation in an interactive cartographic information system are discusse

Nonmechanical parfocal and autofocus features based on wave propagation distribution in lensfree holographic microscopy

Performing long-term cell observations is a non-trivial task for conventional optical microscopy, since it is usually not compatible with environments of an incubator and its temperature and humidity requirements. Lensless holographic microscopy, being entirely based on semiconductor chips without lenses and without any moving parts, has proven to be a very interesting alternative to conventional microscopy. Here, we report on the integration of a computational parfocal feature, which operates based on wave propagation distribution analysis, to perform a fast autofocusing process. This unique non-mechanical focusing approach was implemented to keep the imaged object staying in-focus during continuous long-term and real-time recordings. A light-emitting diode (LED) combined with pinhole setup was used to realize a point light source, leading to a resolution down to 2.76 μm. Our approach delivers not only in-focus sharp images of dynamic cells, but also three-dimensional (3D) information on their (x, y, z)-positions. System reliability tests were conducted inside a sealed incubator to monitor cultures of three different biological living cells (i.e., MIN6, neuroblastoma (SH-SY5Y), and Prorocentrum minimum). Altogether, this autofocusing framework enables new opportunities for highly integrated microscopic imaging and dynamic tracking of moving objects in harsh environments with large sample areas

How Do We Support Technical Tasks in the Age of Augmented Reality? Some Evidence from Prototyping in Mechanical Engineering

Industrial sectors like mechanical engineering currently define themselves primarily through their product business. However, a change can currently be observed. Instead of continuing to engineer products for maximum reliability, solution systems are developed that leverage their performance from services such as maintenance. For these, information supply is an essential factor, since the underlying products are becoming more complex. Additionally, these products are integrating information and communication technology, which can supply technicians, e.g. with actual condition data. To be able to use this information, technicians need service support systems (SSS) that yet exist on mobile and simple wearable devices. This article reports from the development of an SSS-based on augmented reality glasses. The developed system was used to support a LEGO assembly task and evaluated with the Task-Technology Fit model. The result shows that AR glasses can be used for the information supply of technicians but still need further development to allow for adequate service support

Evaluation of depth of field for depth perception in DVR

pre-printIn this paper we present a user study on the use of Depth of Field for depth perception in Direct Volume Rendering. Direct Volume Rendering with Phong shading and perspective projection is used as the baseline. Depth of Field is then added to see its impact on the correct perception of ordinal depth. Accuracy and response time are used as the metrics to evaluate the usefulness of Depth of Field. The onsite user study has two parts: static and dynamic. Eye tracking is used to monitor the gaze of the subjects. From our results we see that though Depth of Field does not act as a proper depth cue in all conditions, it can be used to reinforce the perception of which feature is in front of the other. The best results (high accuracy & fast response time) for correct perception of ordinal depth occurs when the front feature (out of the two features users were to choose from) is in focus and perspective projection is used

Dr.Bokeh: DiffeRentiable Occlusion-aware Bokeh Rendering

Bokeh is widely used in photography to draw attention to the subject while effectively isolating distractions in the background. Computational methods simulate bokeh effects without relying on a physical camera lens. However, in the realm of digital bokeh synthesis, the two main challenges for bokeh synthesis are color bleeding and partial occlusion at object boundaries. Our primary goal is to overcome these two major challenges using physics principles that define bokeh formation. To achieve this, we propose a novel and accurate filtering-based bokeh rendering equation and a physically-based occlusion-aware bokeh renderer, dubbed Dr.Bokeh, which addresses the aforementioned challenges during the rendering stage without the need of post-processing or data-driven approaches. Our rendering algorithm first preprocesses the input RGBD to obtain a layered scene representation. Dr.Bokeh then takes the layered representation and user-defined lens parameters to render photo-realistic lens blur. By softening non-differentiable operations, we make Dr.Bokeh differentiable such that it can be plugged into a machine-learning framework. We perform quantitative and qualitative evaluations on synthetic and real-world images to validate the effectiveness of the rendering quality and the differentiability of our method. We show Dr.Bokeh not only outperforms state-of-the-art bokeh rendering algorithms in terms of photo-realism but also improves the depth quality from depth-from-defocus

Improving everyday computing tasks with head-mounted displays

The proliferation of consumer-affordable head-mounted displays (HMDs) has brought a rash of entertainment applications for this burgeoning technology, but relatively little research has been devoted to exploring its potential home and office productivity applications. Can the unique characteristics of HMDs be leveraged to improve users’ ability to perform everyday computing tasks? My work strives to explore this question. One significant obstacle to using HMDs for everyday tasks is the fact that the real world is occluded while wearing them. Physical keyboards remain the most performant devices for text input, yet using a physical keyboard is difficult when the user can’t see it. I developed a system for aiding users typing on physical keyboards while wearing HMDs and performed a user study demonstrating the efficacy of my system. Building on this foundation, I developed a window manager optimized for use with HMDs and conducted a user survey to gather feedback. This survey provided evidence that HMD-optimized window managers can provide advantages that are difficult or impossible to achieve with standard desktop monitors. Participants also provided suggestions for improvements and extensions to future versions of this window manager. I explored the issue of distance compression, wherein users tend to underestimate distances in virtual environments relative to the real world, which could be problematic for window managers or other productivity applications seeking to leverage the depth dimension through stereoscopy. I also investigated a mitigation technique for distance compression called minification. I conducted multiple user studies, providing evidence that minification makes users’ distance judgments in HMDs more accurate without causing detrimental perceptual side effects. This work also provided some valuable insight into the human perceptual system. Taken together, this work represents valuable steps toward leveraging HMDs for everyday home and office productivity applications. I developed functioning software for this purpose, demonstrated its efficacy through multiple user studies, and also gathered feedback for future directions by having participants use this software in simulated productivity tasks

Surgical outcomes of pars plana vitrectomy with and without internal limiting membrane peeling for symptomatic vitreomacular traction

PURPOSE: To study the long-term anatomic and visual outcomes after pars plana vitrectomy (PPV) with and without internal limiting membrane (ILM) peeling in patients with symptomatic vitreomacular traction (VMT). This study assesses the frequency of complications, changes in visual acuity, and changes in anatomical central macular thickness after macular surgery. METHODS: This retrospective, single-site, single-surgeon study reviewed 40 medical records (45 eyes) of patients at the Beth Israel Deaconess Medical Center requiring PPV with ILM peeling (n=27) or without ILM peeling (n=18) for VMT between the years of 2003 and 2016. Successful surgery was defined as the relief of anatomical traction, and the absence of a second surgery, or any post-operative complications (n=42). Visual acuity was documented for each eye prior to surgery and post surgery. RESULTS: All 27 (100%) eyes that had ILM peeling had successfully resolved macular traction following a single surgery, and 15 of the 18 (83.3%) eyes without ILM peel were successful. None of 27 (0%) eyes that had ILM peeling required a second surgery, nor did they have complications. 3 of the 18 (16.7%) eyes without ILM peeling required a second surgery. Best corrected visual acuity (BCVA, logMAR) improved significantly in both groups: BCVA improved from 0.59 ± 0.29 preoperatively to 0.37 ± 0.25 postoperatively in eyes receiving ILM peeling and from 0.77 ± 0.37 to 0.53 ± 0.37 in eyes with PPV only. Mean change in CMT pre-operatively to post-operatively was found to be greater in eyes with PPV alone, but this difference was not statistically significant. CONCLUSIONS: Our case series shows that PPV with ILM peeling for VMT relieved macular traction better than PPV alone, although there was no significant difference in visual acuity outcomes or central macular thickness between the two groups. Further research is required to validate these findings.2019-07-11T00:00:00

On Generative Adversarial Network Based Synthetic Iris Presentation Attack And Its Detection

Human iris is considered a reliable and accurate modality for biometric recognition due to its unique texture information. Reliability and accuracy of iris biometric modality have prompted its large-scale deployment for critical applications such as border control and national identification projects. The extensive growth of iris recognition systems has raised apprehensions about the susceptibility of these systems to various presentation attacks. In this thesis, a novel iris presentation attack using deep learning based synthetically generated iris images is presented. Utilizing the generative capability of deep convolutional generative adversarial networks and iris quality metrics, a new framework, named as iDCGAN is proposed for creating realistic appearing synthetic iris images. In-depth analysis is performed using quality score distributions of real and synthetically generated iris images to understand the effectiveness of the proposed approach. We also demonstrate that synthetically generated iris images can be used to attack existing iris recognition systems. As synthetically generated iris images can be effectively deployed in iris presentation attacks, it is important to develop accurate iris presentation attack detection algorithms which can distinguish such synthetic iris images from real iris images. For this purpose, a novel structural and textural feature-based iris presentation attack detection framework (DESIST) is proposed. The key emphasis of DESIST is on developing a unified framework for detecting a medley of iris presentation attacks, including synthetic iris. Experimental evaluations showcase the efficacy of the proposed DESIST framework in detecting synthetic iris presentation attacks