A Data-Driven Regularization Model for Stereo and Flow

Data-driven techniques can reliably build semantic correspondence among images. In this paper, we present a new regularization model for stereo or flow through transferring the shape information of the disparity or flow from semantically matched patches in the training database. Compared to previous regularization models based on image appearance alone, we can better resolve local ambiguity of the disparity or flow by considering the semantic information without explicit object modeling. We incorporate this data-driven regularization model into a standard Markov Random Field (MRF) model, inferred with a gradient descent algorithm and learned with a discriminative learning approach. Compared to prior state-of-the-art methods, our full model achieves comparable or better results on the KITTI stereo and flow datasets, and improves results on the Sintel Flow dataset under an online estimation setting.National Science Foundation (U.S.) (CGV 1212849)United States. Office of Naval Research. Multidisciplinary University Research Initiative (Award N00014-09-1-1051

A Compositional Model for Low-Dimensional Image Set Representation

Learning a low-dimensional representation of images is useful for various applications in graphics and computer vision. Existing solutions either require manually specified landmarks for corresponding points in the images, or are restricted to specific objects or shape deformations. This paper alleviates these limitations by imposing a specific model for generating images, the nested composition of color, shape, and appearance. We show that each component can be approximated by a low-dimensional subspace when the others are factored out. Our formulation allows for efficient learning and experiments show encouraging results.Shell Researc

SIFT Flow: Dense Correspondence across Scenes and its Applications

While image alignment has been studied in different areas of computer vision for decades, aligning images depicting different scenes remains a challenging problem. Analogous to optical flow where an image is aligned to its temporally adjacent frame, we propose SIFT flow, a method to align an image to its nearest neighbors in a large image corpus containing a variety of scenes. The SIFT flow algorithm consists of matching densely sampled, pixel-wise SIFT features between two images, while preserving spatial discontinuities. The SIFT features allow robust matching across different scene/object appearances, whereas the discontinuity-preserving spatial model allows matching of objects located at different parts of the scene. Experiments show that the proposed approach robustly aligns complex scene pairs containing significant spatial differences. Based on SIFT flow, we propose an alignment-based large database framework for image analysis and synthesis, where image information is transferred from the nearest neighbors to a query image according to the dense scene correspondence. This framework is demonstrated through concrete applications, such as motion field prediction from a single image, motion synthesis via object transfer, satellite image registration and face recognition

A computational approach for obstruction-free photography

We present a unified computational approach for taking photos through reflecting or occluding elements such as windows and fences. Rather than capturing a single image, we instruct the user to take a short image sequence while slightly moving the camera. Differences that often exist in the relative position of the background and the obstructing elements from the camera allow us to separate them based on their motions, and to recover the desired background scene as if the visual obstructions were not there. We show results on controlled experiments and many real and practical scenarios, including shooting through reflections, fences, and raindrop-covered windows.Shell ResearchUnited States. Office of Naval Research (Navy Fund 6923196

Motion denoising with application to time-lapse photography

Motions can occur over both short and long time scales. We introduce motion denoising, which treats short-term changes as noise, long-term changes as signal, and re-renders a video to reveal the underlying long-term events. We demonstrate motion denoising for time-lapse videos. One of the characteristics of traditional time-lapse imagery is stylized jerkiness, where short-term changes in the scene appear as small and annoying jitters in the video, often obfuscating the underlying temporal events of interest. We apply motion denoising for resynthesizing time-lapse videos showing the long-term evolution of a scene with jerky short-term changes removed. We show that existing filtering approaches are often incapable of achieving this task, and present a novel computational approach to denoise motion without explicit motion analysis. We demonstrate promising experimental results on a set of challenging time-lapse sequences.United States. National Geospatial-Intelligence Agency (NEGI-1582-04-0004)Shell ResearchUnited States. Office of Naval Research. Multidisciplinary University Research Initiative (Grant N00014-06-1-0734)National Science Foundation (U.S.) (0964004

Patient–provider perceptions of diabetes and its impact on self-management: a comparison of African-American and White patients

Aims  To compare patient–provider differences in diabetes-related perceptions between African-American and White patients and to examine its association with self-care behaviours. Methods  One hundred and thirty patient–provider pairs were recruited from the greater Detroit area. Patients and providers completed a survey assessing perceptions about diabetes-related concepts and demographic background. The Diabetes Semantic Differential Scale was used to measure diabetes-related perceptions. Patients also reported the frequency of performing self-care behaviours, including following a healthy eating plan, engaging in physical activity, blood glucose monitoring, and taking medication and/or insulin. Results  There were a greater number of patient–provider differences in diabetes-related perceptions for the African-American patients (nine of 18 concepts) compared with the White patients (four of 18 concepts). Stepwise regression analyses found patients’ semantic differential scores to be significantly associated with five self-care behaviours for African-American patients and two self-care behaviours for White patients. Providers’ semantic differential scores emerged as predictors of self-care behaviours for African-American patients, but not for White patients. Conclusions  Our findings suggest that compared with White patients, African-Americans differ in a greater number of diabetes-related perceptions than their providers. Patients’ and providers’ perceptions of diabetes care concepts have a significant impact on a greater number of self-care behaviours for African-American patients than White patients. Diabet. Med. 25, 341–348 (2008)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72171/1/j.1464-5491.2007.02371.x.pd

Communicating personalised risks from COVID-19: guidelines from an empirical study

As increasing amounts of data accumulate on the effects of the novel coronavirus Sars-CoV-2 and the risk factors that lead to poor outcomes, it is possible to produce personalised estimates of the risks faced by groups of people with different characteristics. The challenge of how to communicate these then becomes apparent. Based on empirical work (total n=5,520, UK) supported by in-person interviews with the public and physicians, we make recommendations on the presentation of such information. These include: using predominantly percentages when communicating the absolute risk, but also providing, for balance, a format which conveys a contrasting (higher) perception of risk (expected frequency out of 10,000); using a visual linear scale cut at an appropriate point to illustrate the maximum risk, explained through an illustrative ‘persona’ who might face that highest level of risk; and providing context to the absolute risk through presenting a range of other ‘personas’ illustrating people who would face risks of a wide range of different levels. These ‘personas’ should have their major risk factors (age, existing health conditions) described. By contrast, giving people absolute likelihoods of other risks they face in an attempt to add context was considered less helpful