Space and camera path reconstruction for omni-directional vision

In this paper, we address the inverse problem of reconstructing a scene as well as the camera motion from the image sequence taken by an omni-directional camera. Our structure from motion results give sharp conditions under which the reconstruction is unique. For example, if there are three points in general position and three omni-directional cameras in general position, a unique reconstruction is possible up to a similarity. We then look at the reconstruction problem with m cameras and n points, where n and m can be large and the over-determined system is solved by least square methods. The reconstruction is robust and generalizes to the case of a dynamic environment where landmarks can move during the movie capture. Possible applications of the result are computer assisted scene reconstruction, 3D scanning, autonomous robot navigation, medical tomography and city reconstructions

Challenges and Solutions for Autonomous Robotic Mobile Manipulation for Outdoor Sample Collection

In refinery, petrochemical, and chemical plants, process technicians collect uncontaminated samples to be analyzed in the quality control laboratory all time and all weather. This traditionally manual operation not only exposes the process technicians to hazardous chemicals, but also imposes an economical burden on the management. The recent development in mobile manipulation provides an opportunity to fully automate the operation of sample collection. This paper reviewed the various challenges in sample collection in terms of navigation of the mobile platform and manipulation of the robotic arm from four aspects, namely mobile robot positioning/attitude using global navigation satellite system (GNSS), vision-based navigation and visual servoing, robotic manipulation, mobile robot path planning and control. This paper further proposed solutions to these challenges and pointed the main direction of development in mobile manipulation

Nonlinear tube-fitting for the analysis of anatomical and functional structures

We are concerned with the estimation of the exterior surface and interior summaries of tube-shaped anatomical structures. This interest is motivated by two distinct scientific goals, one dealing with the distribution of HIV microbicide in the colon and the other with measuring degradation in white-matter tracts in the brain. Our problem is posed as the estimation of the support of a distribution in three dimensions from a sample from that distribution, possibly measured with error. We propose a novel tube-fitting algorithm to construct such estimators. Further, we conduct a simulation study to aid in the choice of a key parameter of the algorithm, and we test our algorithm with validation study tailored to the motivating data sets. Finally, we apply the tube-fitting algorithm to a colon image produced by single photon emission computed tomography (SPECT) and to a white-matter tract image produced using diffusion tensor imaging (DTI).Comment: Published in at http://dx.doi.org/10.1214/10-AOAS384 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Magnetic resonance imaging of lung cancer in the presence of respiratory motion: Dynamic keyhole and audio visual biofeedback

Breath-to-breath variations in breathing can cause image artefacts. Day-to-day variations can cause a disagreement of position and volume between planning and treatment throughout radiotherapy procedures, requiring a larger treatment margin and longer treatment time. An advanced radiotherapy system requires: (1) a fast imaging technique for the compensation of breathing variations and/or (2) a respiratory motion management technique for the control of breathing variations. A novel MRI reconstruction method called “Dynamic keyhole” was proposed as a fast imaging technique. This thesis investigated (1) the concept of this method in terms of the improvement in temporal resolution with healthy volunteer MRI datasets and (2) the applicability of real-time lung tumour localization in terms of the accuracy of tumour motion and shape with lung cancer patient MRI datasets. The dynamic keyhole method achieved an increase in imaging frequency by up to a factor of five when compared with full k-space methods whilst achieving sub-millimetre tumour motion accuracy and preserving tumour shape within 98%. AV biofeedback respiratory guidance was used for healthy volunteers and lung cancer patients. This thesis investigated the impact of AV biofeedback on (1) intra- and inter-fraction lung tumour motion using cine-MRI, (2) inter-fraction lung tumour position and intra-fraction tumour volume using breath-hold MRI and (3) the improvement in image quality and the reduction in scan time using respiratory-gated MRI. AV biofeedback respiratory guidance improved intra- and inter-fraction tumour motion and position reproducibility, and intra-fraction tumour volume consistency. In addition, it was found to improve image quality and reduce scan time. The performance of the dynamic keyhole method and AV biofeedback respiratory guidance shown in this thesis illustrates potential advantages of real-time tumour imaging and tumour motion management in the course of lung cancer radiotherapy