“I get to know them as a whole person”: family physician stories of proximity to patients experiencing social inequity

Canadians’ health outcomes are inextricably tied to social inequities. While family medicine is aptly situated to provide care that addresses social factors through longitudinal knowledge of patients and their contexts, family physicians have come under increased pressure to do more for their patients with less time and resources due to financial and resource demands within primary care. Nursing scholar Ruth Malone has argued that remaining proximal, or close to patients, is a form of resistance to these demands. Using a critical narrative methodology, we conducted 36 interviews with 20 family physicians working with persons experiencing health needs related to social inequity in Ontario, Canada, whose stories expressed and expanded upon Malone’s proximity. Notions of proximity were invoked through descriptions of the role of family physicians in: i) generating physical proximity based on the patients’ needs for more time, space, and care; ii) developing narrative proximity through storytelling over time, both between colleagues and patient communities; and iii) engaging in moral proximity, or recognizing the vulnerabilities of their patients, by going “above and beyond” in their care and advocacy roles inspired by the needs of their patients. The findings add theoretical depth to proximity, extending this conceptualization into a new clinical context. These stories also complement current health services and health policy research that advocates for collaborative primary care approaches, as elements of these approaches are conducive to establishing proximity with patients who need care the most

Application of structured light imaging for high resolution mapping of underwater archaeological sites

This paper presents results from recent work using structured light laser profile imaging to create high resolution bathymetric maps of underwater archaeological sites. Documenting the texture and structure of submerged sites is a difficult task and many applicable acoustic and photographic mapping techniques have recently emerged. This effort was completed to evaluate laser profile imaging in comparison to stereo imaging and high frequency multibeam mapping. A ROV mounted camera and inclined 532 nm sheet laser were used to create profiles of the bottom that were then merged into maps using platform navigation data. These initial results show very promising resolution in comparison to multibeam and stereo reconstructions, particularly in low contrast scenes. At the test sites shown here there were no significant complications related to scattering or attenuation of the laser sheet by the water. The resulting terrain was gridded at 0.25 cm and shows overall centimeter level definition. The largest source of error was related to the calibration of the laser and camera geometry. Results from three small areas show the highest resolution 3D models of a submerged archaeological site to date and demonstrate that laser imaging will be a viable method for accurate three dimensional site mapping and documentation

Terrain Constrained Stereo Correspondence

There is a persistent need in the oceanographic community for accurate three dimensional reconstructions of seafloor structures. To meet this need underwater mapping techniques have expanded to include the use of stereo vision and high frequency multibeam sonar for mapping scenes 10\u27s to 100\u27s of square meters in size. Both techniques have relative advantages and disadvantages that depend on the task at hand and the desired accuracy. In this paper, we develop a method to constrain the often problematic stereo correspondence search to small sections of the image that correspond to estimated ranges along the epipolar lines calculated from coregistered multibeam sonar micro-bathymetry. This approach can be applied to both sparse feature based and dense area-based stereo correspondence techniques. Data were collected on an underwater vehicle survey using a calibrated stereo rig and a multibeam sonar gathering coincident datasets. Overall, the constrained correspondence method shows improvements in the number and reliability of correct matches and allows for reduction in complexity of feature descriptors but it is heavily reliant on the quality of the intrinsic and extrinsic calibration of the camera and sonar systems

Detection of Diffuse Sea Floor Venting Using Structured Light Imaging

Efficiently identifying and localizing diffuse sea floor venting at hydrothermal and cold seep sites is often difficult. Actively venting fluids are usually identified by a temperature induced optical shimmering seen during direct visual inspections or in video data collected by vehicles working close to the sea floor. Relying on such direct methods complicates establishing spatial relations between areas within a survey covering a broad area. Our recent work with a structured light laser system has shown that venting can also be detected in the image data in an automated fashion. A structured light laser system consists of a camera and sheet laser projected at the sea floor. The camera and laser are fixed to a rigid calibrated mount such that the optical axis of the camera and the laser plane intersect at some distance away from the camera, typically 2 to 5 meters. The position of the laser line, visible on the sea floor in the image, can be extracted using standard computer vision techniques (Fig. 1) and used to determine the height of the bottom along the laser line. By collecting images in a survey pattern at a high frame rate, typically 20 to 30 Hz, a bathymetric map can be produced using the individual profiles. In the presence of venting, temperature anomalies refract the laser sheet such that it does not project a crisp and clear line on the sea floor. The laser will instead appear blurred and visible over a larger section of the image. By processing the images to segment out clear laser lines from refracted lines it is possible to identify areas of venting. Our initial approach uses calculated image moments relative to the peak intensity level detected in each column of the image matrix. In the presence of venting the calculated moments differ from those of the undistorted laser shining on the sea floor. Test results from the Kolumbo submarine volcano near Santorini, Greece demonstrate this approach and show the utility of the method for survey work. Test images over active vents are compared to typical sea floor images, allowing for allowing areas of venting to be identified from sequences of images taken during a standard grid survey over the vent field. The use of structured light laser image offers potential for broad area vehicle surveys. The method would also complement direct visual surveys and other acoustic coherence methods that are used to identify the location of fluid flow. AGU session number OS11B-1473

Sonar constrained stereo correspondence for three-dimensional seafloor reconstruction

There is a persistent need in the oceanographic community for accurate three dimensional reconstructions of seafloor structures. To meet this need underwater mapping techniques have expanded to include the use of stereo vision and high frequency multibeam sonar for mapping scenes 10\u27s to 100\u27s of square meters in size. Both techniques have relative advantages and disadvantages that depend on the task at hand and the desired accuracy. In this paper, we develop a method to constrain the often problematic stereo correspondence search to small sections of the image that correspond to estimated ranges along the epipolar lines calculated from coregistered multibeam sonar micro-bathymetry. This approach can be applied to both sparse feature-based and dense area-based stereo correspondence techniques. Data were collected on an underwater vehicle survey using a calibrated stereo rig and a multibeam sonar gathering coincident datasets. Overall, the constrained correspondence method shows improvements in the number and reliability of correct matches and allows for reduction in complexity of feature descriptors but it is reliant on the quality of both intrinsic and extrinsic sensor calibration. © 2010 IEEE

Development of High Resolution Sea Floor Mapping Tools and Techniques

There is a persistent need for high resolution photographic and bathymetric maps of the sea floor for many research areas in marine geology, biology and archaeology. This poster will present recent work using high frequency multibeam sonars, stereo vision and structured light laser imaging techniques to create maps with centimeter resolution for these applications. This research involves the development of new image and sonar processing techniques that combat the typical difficulties of imperfect navigation information, limited sensor ranges and adverse environmental conditions associated with using marine robotic vehicles in the ocean. Data for this work has been collected with the Hercules remotely operated vehicle (ROV), which is part of the Nautilus ocean exploration program, and with our newly developed Lagrangian imaging float. The 2010 Nautilus expedition involved more than 80 technical and scientific collaborators from around the world working for four months at archaeogical and geological sites in the Aegean and Mediterranean Seas. Our new Lagrangian float is novel platform that provides high quality sea floor images with significantly less effort and cost than other current methods. The presented results will show direct comparisons between our visual and acoustic sensing modalities, an in-situ calibration procedure for structured light laser imaging, and the visual data products that can be produced by the Lagrangian float