Evaluating methods for controlling depth perception in stereoscopic cinematography.

Existing stereoscopic imaging algorithms can create static stereoscopic images with perceived depth control function to ensure a compelling 3D viewing experience without visual discomfort. However, current algorithms do not normally support standard Cinematic Storytelling techniques. These techniques, such as object movement, camera motion, and zooming, can result in dynamic scene depth change within and between a series of frames (shots) in stereoscopic cinematography. In this study, we empirically evaluate the following three types of stereoscopic imaging approaches that aim to address this problem. (1) Real-Eye Configuration: set camera separation equal to the nominal human eye interpupillary distance. The perceived depth on the display is identical to the scene depth without any distortion. (2) Mapping Algorithm: map the scene depth to a predefined range on the display to avoid excessive perceived depth. A new method that dynamically adjusts the depth mapping from scene space to display space is presented in addition to an existing fixed depth mapping method. (3) Depth of Field Simulation: apply Depth of Field (DOF) blur effect to stereoscopic images. Only objects that are inside the DOF are viewed in full sharpness. Objects that are far away from the focus plane are blurred. We performed a human-based trial using the ITU-R BT.500-11 Recommendation to compare the depth quality of stereoscopic video sequences generated by the above-mentioned imaging methods. Our results indicate that viewers' practical 3D viewing volumes are different for individual stereoscopic displays and viewers can cope with much larger perceived depth range in viewing stereoscopic cinematography in comparison to static stereoscopic images. Our new dynamic depth mapping method does have an advantage over the fixed depth mapping method in controlling stereo depth perception. The DOF blur effect does not provide the expected improvement for perceived depth quality control in 3D cinematography. We anticipate the results will be of particular interest to 3D filmmaking and real time computer games

An application driven comparison of depth perception on desktop 3D displays.

Desktop 3D displays vary in their optical design and this results in a significant variation in the way in which stereo images are physically displayed on different 3D displays. When precise depth judgements need to be made these differences may become critical to task performance. Applications where this is a particular issue include medical imaging, geoscience and scientific visualization. We investigate perceived depth thresholds for four classes of desktop 3D display; full resolution, row interleaved, column interleaved and colour-column interleaved. Given the same input image resolution we calculate the physical view resolution for each class of display to geometrically predict its minimum perceived depth threshold. To verify our geometric predictions we present the design of a task where viewers are required to judge which of two neighboring squares lies in front of the other. We report results from a trial using this task where participants are randomly asked to judge whether they can perceive one of four levels of image disparity (0,2,4 and 6 pixels) on seven different desktop 3D displays. The results show a strong effect and the task produces reliable results that are sensitive to display differences. However, we conclude that depth judgement performance cannot always be predicted from display geometry alone. Other system factors, including software drivers, electronic interfaces, and individual participant differences must also be considered when choosing a 3D display to make critical depth judgements

Facilitating Undergraduate Learning through Community-Engaged Problem-Based Learning

We used problem-based or experiential learning in our undergraduate Health Policy course to examine food deserts via a health impact assessment (HIA) assignment. A HIA evaluates potential effects on population health before a policy/program is implemented, to improve health and reduce adverse outcomes. We investigated if the HIA assignment facilitated student learning using mixed-methods to descriptively analyze students’ pre-/post-test and peer group assessment surveys, guest lecture reflections, mid-semester evaluations, and HIA research paper reflections. Quantitatively, students’ pre-/post-test ratings of their learning decreased from positive to neutral Likert scale scores, but they rated their group work positively over time. Qualitatively, students learned from community speakers and their research about the challenges of health policy as a pluralistic process and solutions to reducing food insecurity. But, they needed more detailed instructions for their HIA assignment earlier in the semester

An evaluation of reconstruction filters for a path-searching task in 3D

The choice of reconstruction filter used to interpolate between sample points when generating images from volumetric data sets can have an impact on image quality. There are a range of reconstruction filters as well as methods to determine the quality of these filters. While it is well documented that stereoscopy can improve the performance of spatial search tasks, it is not clear how artifacts introduced by the choice of reconstruction filter will impact the performance of these tasks. In this study we report the results of a path-tracing experiment where we assess the effectiveness of stereoscopy and three reconstruction filters in terms of accuracy and response time. Our results suggest that the reconstruction filter can have a significant effect on path-tracing tasks and that stereoscopy can significantly improve accuracy results whilst slightly increasing response time

Advocacy in the tail: Exploring the implications of ‘climategate’ for science journalism and public debate in the digital age

This paper explores the evolving practices of science journalism and public debate in the digital age. The vehicle for this study is the release of digitally stored email correspondence, data and documents from the Climatic Research Unit at the University of East Anglia in the weeks immediately prior to the United Nations Copenhagen Summit (COP-15) in December 2009. Described using the journalistic shorthand of ‘climategate’, and initially promoted through socio-technical networks of bloggers, this episode became a global news story and the subject of several formal reviews. ‘Climategate’ illustrates that media literate critics of anthropogenic explanations of climate change used digital tools to support their cause, making visible selected, newsworthy aspects of scientific information and the practices of scientists. In conclusion, I argue that ‘climategate’ may have profound implications for the production and distribution of science news, and how climate science is represented and debated in the digitally-mediated public sphere

Near-inertial wave scattering by random flows

The impact of a turbulent flow on wind-driven oceanic near-inertial waves is examined using a linearised shallow-water model of the mixed layer. Modelling the flow as a homogeneous and stationary random process with spatial scales comparable to the wavelengths, we derive a transport (or kinetic) equation governing wave-energy transfers in both physical and spectral spaces. This equation describes the scattering of the waves by the flow which results in a redistribution of energy between waves with the same frequency (or, equivalently, with the same wavenumber) and, for isotropic flows, in the isotropisation of the wave field. The time scales for the scattering and isotropisation are obtained explicitly and found to be of the order of tens of days for typical oceanic parameters. The predictions inferred from the transport equation are confirmed by a series of numerical simulations. Two situations in which near-inertial waves are strongly influenced by flow scattering are investigated through dedicated nonlinear shallow-water simulations. In the first, a wavepacket propagating equatorwards as a result from the $\beta$-effect is shown to be slowed down and dispersed both zonally and meridionally by scattering. In the second, waves generated by moving cyclones are shown to be strongly disturbed by scattering, leading again to an increased dispersion.Comment: Accepted for publication in Phys. Rev. Fluid

Examining the independent contribution of prosodic sensitivity to word reading and spelling in early readers

This study was designed to examine the independent contribution of prosodic sensitivity – the rhythmic patterning of speech – to word reading and spelling in a sample of early readers. Ninety-three English-speaking children aged five to six years old (M = 69.28 months, SD = 3.67) were assessed for their prosodic sensitivity, vocabulary knowledge, phonological, and morphological awareness (predictor variables) along with their word reading and spelling (criterion variables). Bivariate (zero-order) correlation analyses revealed that prosodic sensitivity was significantly associated with all other variables in this study. Hierarchical regression analyses revealed that after controlling for individual differences in vocabulary, phonological, and morphological awareness, prosodic sensitivity was still able to explain unique variance in word reading, but was unable to make an independent contribution to spelling. The findings suggest that prosodic sensitivity gives added value to our understanding of children’s reading development

Why people attend science festivals : interests, motivations and self-reported benefits of public engagement with research

As a form of public engagement, science festivals have rapidly expanded in size and number over recent years. However, as with other domains of informal public engagement that are not linked to policy outcomes, existing research does not fully address science festivals’ impacts and popularity.This study adduces evidence from surveys and focus groups to elucidate the perspectives of visitors at a large UK science festival. Results show that visitors value the opportunities science festivals afford to interact with scientific researchers and to encounter different types of science engagement aimed at adults, children and families. The most significant self-reported impact of attending a science festival was the development of increased interest and curiosity about new areas of scientific knowledge within a socially stimulating and enjoyable setting

Cosmic cookery : making a stereoscopic 3D animated movie.

This paper describes our experience making a short stereoscopic movie visualizing the development of structure in the universe during the 13.7 billion years from the Big Bang to the present day. Aimed at a general audience for the Royal Society's 2005 Summer Science Exhibition, the movie illustrates how the latest cosmological theories based on dark matter and dark energy are capable of producing structures as complex as spiral galaxies and allows the viewer to directly compare observations from the real universe with theoretical results. 3D is an inherent feature of the cosmology data sets and stereoscopic visualization provides a natural way to present the images to the viewer, in addition to allowing researchers to visualize these vast, complex data sets. The presentation of the movie used passive, linearly polarized projection onto a 2m wide screen but it was also required to playback on a Sharp RD3D display and in anaglyph projection at venues without dedicated stereoscopic display equipment. Additionally lenticular prints were made from key images in the movie. We discuss the following technical challenges during the stereoscopic production process; 1) Controlling the depth presentation, 2) Editing the stereoscopic sequences, 3) Generating compressed movies in display speci¯c formats. We conclude that the generation of high quality stereoscopic movie content using desktop tools and equipment is feasible. This does require careful quality control and manual intervention but we believe these overheads are worthwhile when presenting inherently 3D data as the result is signi¯cantly increased impact and better understanding of complex 3D scenes