Augmented reality does not make any sense for fixed cameras. Or does it? In this work, we are dealing with static cameras and their usability for interactive augmented reality applications. Knowing ...that the camera does not move makes camera pose estimation both less and more difficult - one does not have to deal with pose change in time, but on the other hand, obtaining some level of understanding of the scene from a single viewpoint is challenging. We propose several ways how to gain advantage from the camera being static and a pipeline of a system for broadcasting a video stream enriched by information needed for its interactive visual augmenting - Interactive Camera Streams, INCAST. We present a proof-of-concept system showing the usability of INCAST on several use-cases - non-interactive demos and simple AR games.
In various applications, a wider area needs to be covered by fiduciary markers but a large marker cannot be used because only a fraction of the area is to be viewed by the camera. Such an area can be ...covered by a number of small markers with unique identifiers. However, with the camera freely moving in the scene and with occluders present, it is difficult to ensure that at least one of the individual markers is completely visible, unless the markers are small and numerous. In that case, the markers are not recognizable from larger distances. In this paper we introduce the concept of Marker Fields which overcome this limitation. The Marker Field covers a large-scale planar (or non-planar) area and it is composed of mutually overlapping partial markers. We propose a particular arrangement of the Marker Field: a Uniform Checker-Board Marker Field, which is a black- and-white checkerboard whose square modules are defined by aperiodic 4-orientable binary n 2 -window arrays (De Bruijn tori). We propose a genetic algorithm for construction of 4-orientable n 2 window arrays. We used a supercomputer to synthesize large 4-orientable 4 2 window arrays and offer them publicly for downloading. We prototyped an algorithm for detection of the checkerboard marker fields and measured its performance. When processing input video from a cellphone camera, the algorithm visits only about 5 % of image pixels for reliable detection and the processing time is about 1 ms on a mid-range PC processor. The Uniform Marker Field increases freedom of camera movement, especially with occluders present in the scene. The detection algorithm is efficient and real-time marker field detection will be feasible on ultramobile devices.
Abstract
Background
IL-17 producing CD8+ T cells (Tc17) expressing a specific immune signature (CD6high, CD39, CD69, PD-1, CD27low) were shown to be associated with active Crohn’s Disease (CD) and ...inform flare free survival. Here, we addressed the question whether Tc17 cells and their signature also correlate with response of CD patients to therapies with antibodies targeting TNFα or IL-12/23.
Methods
Peripheral blood mononuclear cells were longitudinally collected from CD patients prior to and up to 35 weeks after initiation of therapy with either TNF antibodies or ustekinumab and CD8+ T cells were analyzed by flow cytometry. Results were correlated with clinical outcomes.
Results
We analyzed dynamic changes during treatment in blood samples of 36 CD patients initiating anti-TNF (n = 14) or ustekinumab therapy (N = 22). Baseline Tc17 frequencies differed between ustekinumab and anti-TNF treatment groups, with significantly higher frequencies in the ustekinumab group. This may be due to differences in the baseline patient characteristics; while ustekinumab treated patients were all previously treated with anti-TNF-antibodies, most of the anti-TNF treated patients were naïve to biologics. Indeed, Tc17 frequencies increased during anti-TNF treatment, while Tc17 frequencies were reduced at follow up in the ustekinumab group. However, Tc17 frequencies in the peripheral blood at baseline did not correlate with response to either therapy, nor did the frequencies of Tc17 cells expressing Tc17 signature proteins. The expression of Tc17 signature proteins by IL-17A producing CD8+ T cells did not change significantly during follow up, suggesting that the Tc17 signature was preserved during anti-TNF and ustekinumab therapy. We did not observe major changes in the production of pro-inflammatory cytokines by Tc17 cells during therapy.
Conclusion
Our data suggest that despite playing a pathogenic role in CD, Tc17 cells with a distinct immune signature do not directly correlate with response to therapy with anti-TNF agents or ustekinumab. However, anti-TNF therapy may skew CD8 T cell differentiation towards a Tc17 phenotype, which may have an impact on long term disease outcomes and should be investigated further.
We introduce here an improved design of the Uniform Marker Fields and an algorithm for their fast and reliable detection. Our concept of the marker field is designed so that it can be detected and ...recognized for camera pose estimation: in various lighting conditions, under a severe perspective, while heavily occluded, and under a strong motion blur. Our marker field detection harnesses the fact that the edges within the marker field meet at two vanishing points and that the projected planar grid of squares can be defined by a detectable mathematical formalism. The modules of the grid are grey scale and the locations within the marker field are defined by the edges between the modules. The assumption that the marker field is planar allows for a very cheap and reliable camera pose estimation in the captured scene. The detection rates and accuracy are slightly better compared to state-of-the-art marker-based solutions. At the same time, and more importantly, our detector of the marker field is several times faster and the reliable real-time detection can be thus achieved on mobile and low-power devices. We show three targeted applications where the planarity is assured and where the presented marker field design and detection algorithm provide a reliable and extremely fast solution.
This collected volume presents research focusing on the interaction of domestic, foreign, and transnational actors in the process of the construction of national interests. The contributors ...concentrate on the extent to which the role of non-state actors has strengthened the formulating of national interests of the Slovak Republic in the post-integration period. The book addresses academic readers as well as everyone interested in Slovakia and its recent development.
In this article, we propose an instant matchmoving solution for green screen. It uses a recent technique of planar uniform marker fields. Marker fields are an extension of planar markers used in ...augmented reality, offering better reliability and performance suitable for our task: tolerance to occlusion, speed of detection, and use of arbitrary low-contrast colors. We show that marker fields of shades of green (or blue or other color) can be used to obtain an instant and effortless camera pose estimation. We provide exemplar applications of the presented technique: virtual camera/simulcam and live storyboarding or shot prototyping. The matchmoving technique based on marker fields of shades of green is very computationally efficient - our measurements show that the matchmoving preview and living storyboard editing and recording can be easily done on today's ultramobile devices. Our technique is thus available to anyone at low cost and with easy setup, opening space for new levels of filmmakers' creative expression.
The objective of the study was to determine the impact of a lactate- and an acetate-based hemofiltration replacement fluid (HF) on the acid-base status in patients with acute renal failure (ARF) and ...continuous venovenous hemofiltration (CVVH). The prospective, cohort study was carried out in the intensive care unit of the Heinrich-Heine University Hospital, Düsseldorf, FRG. Subjects were 84 critically ill patients with ARF and CVVH. Fifty-two patients were subjected to lactate-based (group 1) and 32 to acetate-based hemofiltration (group 2). Thirty-eight patients had a septic, 46 a cardiovascular origin of the ARF. Creatinine, BUN, serum bicarbonate, arterial pH, lactate and APACHE II score were noted daily. Mean CVVH duration was 9.8 ± 8.1 days; mortality was 65%. The groups did not differ with regard to the main clinical parameters. Lacate-based hemofiltration led to significantly higher serum bicarbonate and arterial pH values as compared to the acetate-based hemofiltration. Baseline serum bicarbonate values were 23.3 ± 8.3 mmol/L in group 1 and 21.6 ± 4.3 mmol/L in group 2 (NS); values at 48 h after initiating CVVH treatment were 25.7 ± 3.8 mmol/L and 20.6 ± 3.1 mmol/L, respectively (p < 0.001). Arterial pH prior to CVVH treatment was 7.36 ± 0.1 in group 1 and 7.34 ± 0.1 in group 2 (NS), and 7.43 ± 0.07 versus 7.37 ± 0.06 (p < 0.001) on day 2. These findings were maintained throughout therapy. While a lack of increase in serum bicarbonate and arterial pH was correlated to a poor prognosis in lactate-based hemofiltration, no such observation could be made in acetate-based hemofiltration. Septic patients did not differ in their acid-base status from nonseptic patients. Lactic acidosis occurred in 8 septic patients irrespective of the substitution fluid. All 8 patients died. There was a significant increase in HCO3 and arterial pH values in lactate-based as compared to acetate-based HF.
Erythropoietin (Epo) is a glycoprotein hormone produced in the kidney in response to hypoxia or anaemia. In acute renal failure (ARF) anaemia also occurs and current opinion is that Epo production is ...depressed with inappropriately low plasma levels throughout the uraemic phase. Our study was designed to determine the excretion of Epo in patients with ARF. Fifty-nine ventilated patients were studied, 39 with ARF and continuous veno-venous haemofiltration therapy (group 1) and 13 patients with normal renal function who served as a control group (group 2). All patients with ARF were anaemic and needed a mean transfusion of 0.6 units/day. Values for vitamin B12, folic acid, serum iron and ferritin were normal. While patients with normal renal function had Epo values within the normal range, patients with ARF had significantly higher values at the onset of haemofiltration therapy. Mean Epo (mean +/- SEM) values on days 0-2 were 92.6 +/- 11.7 mU/ml in group 1 and 16.5 +/- 6.4 mU/ml in group 2 (p < 0.0002). Epo levels declined in group 1 to 49 +/- 10.5 mU/ml on days 9 and 10 compared to 23 +/- 9.1 mU/ml in group 2 (ns). These values were maintained until the end of the observation period. No differences were seen between oliguric and non-oliguric patients. Our data show that patients with ARF have increased Epo levels at the beginning of the disease with a strong tendency to decrease, suggesting that there might be inadequate Epo levels during the course of acute renal failure.
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