Camera Trajectory Estimation using Inertial Sensor Measurements and Structure fom Motion Results

This paper describes an approach to estimating the trajectory of a moving camera based on the measurements acquired with an inertial sensor and estimates obtained by applying a structure from motion algorithm to a small set of keyframes in the video sequence. The problem is formulated as an offline trajectory fitting task rather than an online integration problem. This approach avoids many of the issues usually associated with inertial estimation schemes. One of the main advantages of the proposed technique is that it can be applied in situations where approaches based on feature tracking would have significant difficulties. Results obtained by applying the procedure to extended sequences acquired with both conventional and omnidirectional cameras are presented

Human Robot Interaction and Usability Studies for a Smart Wheelchair

We build on previous work [12], [14] on the development of a computer controlled wheelchair equipped with a suite of sensors and a novel interface for human-robot interaction. In this paper, we present experimental results and usability studies for the wheelchair. The architecture for human-robot interaction is hierarchical, with the lowest level corresponding to trajectory control, the intermediate level being behavioral and the highest level involving the composition of behaviors and navigation. Our experimental results illustrate the benefits of a shared-control paradigm where the human operator selects the appropriate hehavior(s) or goals while the software is responsible for executing behaviors and generating safe trajectories. Experiments with human users highlight advantages of augmentation in wheelchairs

Effects of Polyethylene Glycol-Induced Water Stress on the Physiological and Biochemical Responses of Different Sorghum Genotypes

Globally, abiotic stress is the primary cause of crop loss, reducing the average yields of most major crop plants by more than 50% (Bray et. al., 2000). Drought stress is one of the most widespread environmental stresses when the total area of arable land is classified according to the occurrence of various stress factors (Arora et al., 2002). Drought and other abiotic stresses limit the photosynthetic activity of various crops, which in turn reduces the production of photosynthetic assimilates. Almost every developmental stage of the plant is affected by water stress. However, it has been observed that drought stress is more damaging to plants at the growth and germination stages, affecting seedling shoot length, flowering, and root length (Khayatnezhad, et al., 2010

Evaluation of changes in random blood glucose and body mass index during and after completion of chemotherapy in children with acute lymphoblastic leukemia

PurposeImproved survival of patients with childhood acute lymphoblastic leukemia (ALL) has drawn attention to the potential for late consequences of previous treatments among survivors, including metabolic syndrome. In this study, we evaluated changes in 3 parameters, namely, random blood glucose, body mass index (BMI), and Z score for BMI (Z-BMI), in children with ALL during chemotherapy and after completion of treatment.MethodsPatients newly diagnosed with ALL from January, 2005 to December, 2008 at Saint Mary's Hospital, The Catholic University of Korea, who completed treatment with chemotherapy only were included (n=107). Random glucose, BMI, and Z-BMI were recorded at 5 intervals: at diagnosis, before maintenance treatment, at completion of maintenance treatment, and 6 and 12 months after completion of maintenance treatment. Similar analyses were conducted on 2 subcohorts based on ALL risk groups.ResultsFor random glucose, a paired comparison showed significantly lower levels at 12 months post-treatment compared to those at initial diagnosis (P<0.001) and before maintenance (P<0.001). The Z-BMI score was significantly higher before maintenance than at diagnosis (P<0.001), but decreased significantly at the end of treatment (P<0.001) and remained low at 6 months (P<0.001) and 12 months (P<0.001) post-treatment. Similar results were obtained upon analysis of risk group-based subcohorts.ConclusionFor a cohort of ALL patients treated without allogeneic transplantation or cranial irradiation, decrease in random glucose and Z-BMI after completion of chemotherapy does not indicate future glucose intolerance or obesity

Outcome of allogeneic hematopoietic stem cell transplantation for childhood acute lymphoblastic leukemia in second complete remission: a single institution study

PurposeThe survival rate for childhood acute lymphoblastic leukemia (ALL) has improved significantly. However, overall prognosis for the 20 to 25% of patients who relapse is poor, and allogeneic hematopoietic stem cell transplantation (HSCT) offers the best chance for cure. In this study, we identified significant prognostic variables by analyzing the outcomes of allogeneic HSCT in ALL patients in second complete remission (CR).MethodsFifty-three ALL patients (42 men, 79%) who received HSCT in second CR from August 1991 to February 2009 were included (26 sibling donor HSCTs, 49%; 42 bone marrow transplantations, 79%). Study endpoints included cumulative incidence of acute and chronic graft-versus-host disease (GVHD), relapse, 1-year transplant-related mortality (TRM), disease-free survival (DFS), and overall survival (OS).ResultsCumulative incidences of acute GVHD (grade 2 or above) and chronic GVHD were 45.3% and 28.5%, respectively. The estimated 5-year DFS and OS for the cohort was 45.2±6.8% and 48.3±7%, respectively. Only donor type, i.e., sibling versus unrelated, showed significant correlation with DFS in multivariate analysis (P=0.010). The rates of relapse and 1 year TRM were 28.9±6.4% and 26.4±6.1%, respectively, and unrelated donor HSCT (P=0.002) and HLA mismatch (P=0.022) were significantly correlated with increased TRM in univariate analysis.ConclusionIn this single institution study spanning more than 17 years, sibling donor HSCT was the only factor predicting a favorable result in multivariate analysis, possibly due to increased TRM resulting from unrelated donor HSCT

SEALONE (Safety and Efficacy of Coronary Computed Tomography Angiography with Low Dose in Patients Visiting Emergency Room) trial: study protocol for a randomized controlled trial

Objective Chest pain is one of the most common complaints in the emergency department (ED). Cardiac computed tomography angiography (CCTA) is a frequently used tool for the early triage of patients with low- to intermediate-risk acute chest pain. We present a study protocol for a multicenter prospective randomized controlled clinical trial testing the hypothesis that a low-dose CCTA protocol using prospective electrocardiogram (ECG)-triggering and limited-scan range can provide sufficient diagnostic safety for early triage of patients with acute chest pain. Methods The trial will include 681 younger adult (aged 20 to 55) patients visiting EDs of three academic hospitals for acute chest pain or equivalent symptoms who require further evaluation to rule out acute coronary syndrome. Participants will be randomly allocated to either low-dose or conventional CCTA protocol at a 2:1 ratio. The low-dose group will undergo CCTA with prospective ECG-triggering and restricted scan range from sub-carina to heart base. The conventional protocol group will undergo CCTA with retrospective ECG-gating covering the entire chest. Patient disposition is determined based on computed tomography findings and clinical progression and all patients are followed for a month. The primary objective is to prove that the chance of experiencing any hard event within 30 days after a negative low-dose CCTA is less than 1%. The secondary objectives are comparisons of the amount of radiation exposure, ED length of stay and overall cost. Results and Conclusion Our low-dose protocol is readily applicable to current multi-detector computed tomography devices. If this study proves its safety and efficacy, dose-reduction without purchasing of expensive newer devices would be possible

Occlusion detection in multi-baseline stereo

Identifying occlusion is a challenging problem for general stereo algorithms. There have been some efforts to detect occlusion regions. In these approaches, occlusion detection is either implicitly incorporated into the matching process or is invoked as a post processing step after initial disparity estimation. However, the conventional methods of treating occlusion have limitations in that they do not explicitly find evidence of occlusion. As a result, occlusion boundaries are often poorly localized. This in turn, results in blurred disparity estimates around depth discontinuities, which obscures important information such as object boundaries. We propose a novel method to detect occlusions and occluding contours. Instead of inferring occlusion from disparity estimates, we try to explicitly find occlusions from confirming evidence. We use the fact that occlusions generate photometric inconsistencies and we search for decorrelations in the disparity space image. We present an analysis of the structure of the disparity space image which utilizes its duality with the epipolar plane image. Our occlusion analysis also allows us to eliminate incorrect matches by exploiting the structure of these disparity space images. From the detected occlusion regions, we extract occluding contours which are aligned with the edges of foreground objects. In this thesis, we also describe how the sparse disparity and discontinuity estimates produced by the proposed method can be used to accurately reconstruct a dense disparity map

Occlusion detection in multi-baseline stereo

Identifying occlusion is a challenging problem for general stereo algorithms. There have been some efforts to detect occlusion regions. In these approaches, occlusion detection is either implicitly incorporated into the matching process or is invoked as a post processing step after initial disparity estimation. However, the conventional methods of treating occlusion have limitations in that they do not explicitly find evidence of occlusion. As a result, occlusion boundaries are often poorly localized. This in turn, results in blurred disparity estimates around depth discontinuities, which obscures important information such as object boundaries. We propose a novel method to detect occlusions and occluding contours. Instead of inferring occlusion from disparity estimates, we try to explicitly find occlusions from confirming evidence. We use the fact that occlusions generate photometric inconsistencies and we search for decorrelations in the disparity space image. We present an analysis of the structure of the disparity space image which utilizes its duality with the epipolar plane image. Our occlusion analysis also allows us to eliminate incorrect matches by exploiting the structure of these disparity space images. From the detected occlusion regions, we extract occluding contours which are aligned with the edges of foreground objects. In this thesis, we also describe how the sparse disparity and discontinuity estimates produced by the proposed method can be used to accurately reconstruct a dense disparity map

Sensor Based Door Navigation for a Nonholonomic Vehicle

This paper presents a sensor based algorithm for guiding a nonholonomic platform, such as a wheelchair, through a doorway. The controller uses information from a camera system and a laser range finder to perform image-based navigation. Simulations of the resultant switching controller are presented along with experimental results. A simple obstacle avoidance algorithm is also implemented on the experimental platform. Finally, we have considered the input of limited field-of-view constraints on this controller. All of these components together lead to a modal, image-based approach that will safely and robustly navigate a nonholonomic robot with sensor constraints through a doorway