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Effects of light refraction on the accuracy of camera calibration and reconstruction in underwater motion analysis 总被引:1,自引:0,他引:1
Kwon YH Casebolt JB 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(2):315-340
One of the most serious obstacles to accurate quantification of the underwater motion of a swimmer's body is image deformation caused by refraction. Refraction occurs at the water-air interface plane (glass) owing to the density difference. Camera calibration-reconstruction algorithms commonly used in aquatic research do not have the capability to correct this refraction-induced nonlinear image deformation and produce large reconstruction errors. The aim of this paper is to provide a thorough review of: the nature of the refraction-induced image deformation and its behaviour in underwater object-space plane reconstruction; the intrinsic shortcomings of the Direct Linear Transformation (DLT) method in underwater motion analysis; experimental conditions that interact with refraction; and alternative algorithms and strategies that can be used to improve the calibration-reconstruction accuracy. Although it is impossible to remove the refraction error completely in conventional camera calibration-reconstruction methods, it is possible to improve the accuracy to some extent by manipulating experimental conditions or calibration frame characteristics. Alternative algorithms, such as the localized DLT and the double-plane method are also available for error reduction. The ultimate solution for the refraction problem is to develop underwater camera calibration and reconstruction algorithms that have the capability to correct refraction. 相似文献
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Collins B Linton A Merril J Pomerantz K Winthrop S 《Medical reference services quarterly》1992,11(4):1-9
Computers are integral to medical practice, education, and research. While medical students learn computer skills during their training, many practicing physicians do not have the same computer experience. To familiarize this group with the exciting developments in medical informatics, the Himmelfarb Health Sciences Library and Department of Computer Medicine at the George Washington University Medical Center organized a workshop "Introducing Your Office Computer!" for attending physicians. The workshop featured a short lecture/video presentation on computer applications in medicine followed by a "computer fair" of five computer applications. Eleven physicians attended the workshop. Feedback was very positive; many called later to request more detailed instructions on using the programs demonstrated. It was a valuable experience for the staff, and new bridges were built between departments and clients. 相似文献
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The preliminary building program suggested in this paper makes use of outlines, graphs, charts, and lists, rather than long-winded paragraphs, to describe the needs, objectives, and philosophy of the library. It is hoped that a short, concise, but detailed, report using these methods will save time and make the report more attractive to read, thereby encouraging the many people who will need to assist in the building planning to use the report. 相似文献